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A Keratocyst in the Buccal Mucosa with the Features of Keratocystic Odontogenic Tumor

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The Open Dentistry Journal
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Kazuhiko Yamamoto at Nara Medical University
Kazuhiko Yamamoto
Yumiko Matsusue
Yumiko Matsusue
Yumiko Matsusue
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Miyako Kurihara
Miyako Kurihara
Miyako Kurihara
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Yuka Takahashi
Yuka Takahashi
Yuka Takahashi
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Abstract and Figures

A 74-year-old male patient consulted us for an elastic firm mass in the right buccal mucosa. CT examination revealed a well-circumscribed oval cystic lesion in the anterior region of the masseter muscle. On MRI, the lesion showed a low signal on T1-weighted image and a high signal on T2-weighted image. Aspiration biopsy demonstrated the presence of squamous cells in whitish liquid. Under the diagnosis of epidermoid cyst, the lesion was intraorally extirpated under general anesthesia. The lesion was cystic at the size of 30 × 25mm. Histologically, the cyst wall was lined with parakeratinized squamous epithelium corrugated on its surface, the basal layer of which consisted of cuboidal cells showing palisading of the nuclei. Immunohistochemically, the lining epithelium was positive for CK17 and negative for CK10. The basal and suprabasal cells were labeled for Ki-67 at a relatively high rate. These features are compatible with those of keratocystic odontogenic tumor.
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152 The Open Dentistry Journal, 2013, 7, 152-156
1874-2106/13 2013 Bentham Open
Open Access
A Keratocyst in the Buccal Mucosa with the Features of Keratocystic
Odontogenic Tumor
Kazuhiko Yamamoto*, Yumiko Matsusue, Miyako Kurihara, Yuka Takahashi and Tadaaki Kirita
Department of Oral and Maxillofacial Surgery, Nara Medical University
Abstract: A 74-year-old male patient consulted us for an elastic firm mass in the right buccal mucosa. CT examination
revealed a well-circumscribed oval cystic lesion in the anterior region of the masseter muscle. On MRI, the lesion showed
a low signal on T1-weighted image and a high signal on T2-weighted image. Aspiration biopsy demonstrated the presence
of squamous cells in whitish liquid. Under the diagnosis of epidermoid cyst, the lesion was intraorally extirpated under
general anesthesia. The lesion was cystic at the size of 30 × 25mm. Histologically, the cyst wall was lined with parak-
eratinized squamous epithelium corrugated on its surface, the basal layer of which consisted of cuboidal cells showing
palisading of the nuclei. Immunohistochemically, the lining epithelium was positive for CK17 and negative for CK10.
The basal and suprabasal cells were labeled for Ki-67 at a relatively high rate. These features are compatible with those of
keratocystic odontogenic tumor.
Keywords: Buccal mucosa, cutaneous keratocyst, epidermoid cyst, keratocystic odontogenic tumor, nevoid basal cell carci-
noma syndrome, parakeratinization.
INTRODUCTION
Keratocystic odontogenic tumor (KCOT) is one of the
most common odontogenic tumors of ectodermal origin. It is
categorized as a benign odontogenic tumor in the WHO clas-
sification 2005 [1] because of its neoplastic potential and
high recurrence rate. KCOT generally originates from the
remnant of dental lamina or from basal cells of the oral epi-
thelium [1]. It predominantly develops in the mandible or
maxilla [2, 3], and occasionally on the gingiva as a periph-
eral type of manifestation [3, 4]. Interestingly, keratocysts in
the buccal mucosa with similar histological features of
KCOT have been reported in the recent literature [5-7]. It has
not been proven whether these cysts are really odontogenic
or originated from other tissues [7]; therefore, a case of
keratocyst in the buccal mucosa is worthy of attention.
In this report, we present a case of keratocyst developing
in the right buccal mucosa with the features of KCOT.
CASE REPORT
A 74-year-old man consulted our clinic with a complaint
of swelling in the right buccal region. The patient noticed the
swelling 5 years ago and had received aspiration therapy
repeatedly to reduce the swelling. He was generally healthy
and had no medical history. On examination, an elastic firm,
movable mass of 50mm was palpable in the right buccal re-
gion (Fig. 1). The overlying mucous membrane was normal.
*Address correspondence to this author at the Department of Oral and Max-
illofacial Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara
634-8522, Japan; Tel/Fax: +81-744-29-8875;
E-mail: kazuyama@naramed-u.ac.jp
The mass was not adhesive to either the mucous membrane
or the skin. The maxilla was totally edentulous and only bi-
lateral canines and the left first premolar were present in the
mandible. Hypoesthesia or palsy of the right face, trismus,
swelling of cervical lymph nodes or the right parotid gland
was not observed. CT examination revealed a well-
circumscribed oval cystic lesion of 35 mm with the density
slightly less than that of muscle in the anterior region of the
masseter muscle (Fig. 2a). On MRI, the lesion showed a low
signal on the T1-weighted image and a heterogeneous high
signal on the T2-weighted image including intermediate sig-
nal in the under portion (Fig. 2bc). Aspiration through the
buccal skin revealed whitish liquid with squamous cells and
shadow cells with a few neutrophils and lymphocytes in the
cytological examination.
The clinical diagnosis of epidermoid cyst at the right
buccal mucosa was made. The lesion was intraorally extir-
pated under general anesthesia through the incision along the
anterior border of the mandibular ramus (Fig. 3). Detach-
ment of the lesion from the surrounding tissue was relatively
easy. Stensen’s duct was not related to the lesion. The wound
was closed after placing a silicon drain. Wound healing is
good and no sign of recurrence has been observed for more
than 4 years after the surgery.
The lesion was cystic, 30 × 25mm, weighed about 6g and
contained brown serous liquid with a few cellular debris or
keratin scale (Fig. 4). Histologically, the lesion was lined
with squamous epithelium with parakeratinization corru-
gated on the surface (Fig. 5a). The basal layer consisted of
cuboidal cells showing palisading of the nuclei and a smooth
border (Fig. 5b). No daughter cysts, epithelial islands, hair
A keratocyst in the Buccal Mucosa The Open Dentistry Journal, 2013, Volume 7 153
Fig. (1). Intraoral finding
Swelling is observed at the right buccal mucosa (dotted area) posterior to the orifice of Stensen’s duct (arrow head).
Fig. (2). Contd…
154 The Open Dentistry Journal, 2013, Volume 7 Yamamoto et al.
Fig. (2). Imaging
a: Axial CT, b: Axial MRI (T1WI), c: Axial MRI (T2WI)
A well-circumscribed low density mass is observed in the right buccal region anterior to the masseter muscle in CT (arrow head). It shows a
low signal on T1-weighted MRI and a heterogeneous high signal on T2-weighted MRI (arrow head).
Fig. (3). Operative finding
A well-circumscribed mass is exposed anteriorly to the masseter muscle.
Fig. (4). Extirpated lesion
The lesion is cystic and covered with a thin smooth wall.
A keratocyst in the Buccal Mucosa The Open Dentistry Journal, 2013, Volume 7 155
follicles or sebaceous glands were found in the cyst wall.
Immunohistochemically, the lining epithelium was positive
for CK17 (Fig. 6a) and negative for CK10 (Fig. 6b). The
basal and suprabasal cells were labeled for Ki-67 (Fig. 6c) at
a relatively high rate, indicating high proliferation potential.
These features are compatible with those of KCOT.
DISCUSSION
The diagnosis of KCOT is based on its characteristic
histological features [8] and is not difficult for a typical kera-
tocyst in the jawbone; however, the diagnosis of KCOT is
controversial for a keratocyst in the buccal mucosa, even
though it has similar histological features to KCOT. Since
keratocysts in the buccal mucosa can originate from either
odontogenic or epidermal tissue, a definite diagnosis cannot
be made in the absence of the obvious evidence of the origi-
nating tissue. Several lesions should be differentiated from
KCOT.
Epidermoid cyst with similar histological features to
KCOT may develop in the buccal mucosa; however, there
are several differences between KCOT and an epidermoid
cyst. The preferred site of KCOT is apparently unrelated to
the line of closure of the embryonic fusion plane. Histologi-
cally, the lining epithelium of KCOT shows characteristic
palisading of cuboidal basal cells and parakeratinization with
a corrugated surface. A different pattern of cytokeratin ex-
pression is also helpful for differential diagnosis [7]. CK10,
which is specific to a cornified surface such as skin, was
negative in KCOT. On the other hand, CK17 was positive in
KCOT, but negative in epidermoid and orthokeratinized
odontogenic cysts [9]. Ki-67-labeled cells were higher in
KCOT, suggesting higher proliferation potential. Predomi-
nant suprabasal distribution of Ki-67-labeled cells is also
characteristic in KCOT.
Keratocyst originating from skin adnexa such as hair fol-
licles and sebaceous glands may ectopically occur in the
buccal mucosa [7]. In addition, cutaneous keratocyst, which
is generally prevalent in patients with nevoid basal cell car-
Fig. (5). Histological findings
a: The cyst wall is lined with parakeratinized squamous cells with a
corrugated surface.
b: Nuclei of the cells in the basal layer are palisaded. The rete ridge
of the epithelium is not evident.
Fig. (6). Immunohistochemical findings
Immunohistochemical staining was performed using serial sections
of the specimen shown in Fig. (5b).
a: CK17 (E3; Dako)
b: CK10 (DE-K10; Dako)
c: Ki-67 (MIB-1; Dako)
156 The Open Dentistry Journal, 2013, Volume 7 Yamamoto et al.
cinoma syndrome [10, 11], can also develop independently
of the syndrome [12]. KCOT can be differentiated from cu-
taneous cystic lesions such as trichilemmal cyst and steato-
cystoma by its catagen pattern and the presence of piloseba-
ceous units, respectively [12], even if these develop in the
buccal mucosa; however, cutaneous keratocysts resembling
steatocystoma and lacking pilosebaceous units are quite dif-
ficult to differentiate from KCOT, since the corrugated ana-
gen-like lining of these keratocysts is quite similar to that of
KCOT [13]. Furthermore, the lining epithelium of steato-
cystoma, not of sebaceous cells, shows a similar pattern of
cytokeratin expression to KCOT [7,14]. Cutaneous kerato-
cysts rarely occur because once a true follicular cyst devel-
ops from the isthmus of a hair follicle, its lining possibly
adopts a catagen pattern [13]; however, the ectopic develop-
ment of a cutaneous keratocyst in the buccal mucosa cannot
be completely excluded.
The mechanism by which KCOT can develop in the buc-
cal mucosa is not well known. Since KCOT is considered to
originate from the remnants of dental lamina, these cells
should be displaced in the buccal mucosa and persist during
embryogenesis [8]. Recent embryological reports [15,16]
describing the developmental relationship between decidu-
ous dentition and the oral vestibule may give an important
clue. According to these papers [15,16], the vestibular struc-
ture involved in the formation of the oral vestibule and buc-
cal mucosa is reiteratively intermigrated with the dental epi-
thelium around the upper molar areas during tooth forma-
tion. These findings suggest that the remnants of dental lam-
ina entrapped in the buccal tissue during embryogenesis may
develop a keratocyst with the features of KCOT. Other odon-
togenic lesions such as ameloblastoma and odnotoma devel-
oped in the buccal mucosa were also reported [17, 18]. This
hypothesis can explain why these odontogenic lesions in the
buccal mucosa uniformly develop around the parotid papilla.
In summary, a keratocyst in the buccal mucosa with the
features of KCOT is reported. Although a definite diagnosis
of KCOT cannot be made, an odontogenic origin is sus-
pected from the histological features and the immunohisto-
chemical pattern of the lesion.
CONFLICT OF INTEREST
The authors confirm that this article content has no con-
flicts of interest.
ACKNOWLEDGEMENTS
Declared none.
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Received: July 16, 2013 Revised: September 30, 2013 Accepted: October 01, 2013
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... Soft-tissue keratocysts (STK) are cysts of uncertain origin that arise within the soft tissues of the oral and maxillofacial region exhibiting the typical histological features of odontogenic keratocyst (OKC) [1][2][3], with less than 20 cases reported in the English-language literature to date, most of them as single case reports (Table 1) [4][5][6][7][8][9][10][11][12][13][14][15][16]. ...
... The third case was an otherwise healthy 74-year-old woman who presented with a painful swelling in the left buccal mucosa of unknown duration (Fig. 3). She claimed pharynx [10], however, the remaining cases all arose within the buccal space or mucosa [4][5][6][7][8][11][12][13][14][15][16]. The average cyst size reported was 30 mm, frequently causing facial asymmetry (7 cases, 44%) [4,7,11,[13][14][15][16] and occasionally associated with pain (4 cases, 25%) [4,8,9,12]. ...
... She claimed pharynx [10], however, the remaining cases all arose within the buccal space or mucosa [4][5][6][7][8][11][12][13][14][15][16]. The average cyst size reported was 30 mm, frequently causing facial asymmetry (7 cases, 44%) [4,7,11,[13][14][15][16] and occasionally associated with pain (4 cases, 25%) [4,8,9,12]. These clinical features contrast with intraosseous OKCs that are often asymptomatic and scarcely present detectable swelling [1,2]. ...
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Objective To describe the clinicopathological features of 3 new cases of soft-tissue keratocyst (STK) of the buccal mucosa from Brazil. Materials and methods Clinical data from 3 patients diagnosed with STK were obtained from the archives of the Laboratory of Oral Pathology at the Federal University of Rio de Janeiro– Brazil from 2020 to 2023. Two oral pathologists reviewed conventional hematoxylin and eosin-stained slides of each case. Immunohistochemical stainings for CK19, Bcl-2, CD138, D2-40, EMA, and Ki-67 were performed in all cases. Results Case 1 was a 58-year-old man with a 2-year history of painless swelling of the right buccal mucosa, measuring approximately 5 cm. Case 2 was of a 44-year-old man with a painful swelling in the left buccal mucosa lasting 3 years with drainage to the oral cavity. Case 3 was of a 74-year-old woman with a painful swelling in the left buccal mucosa of unknown duration. Microscopic evaluation of all 3 cases revealed a cyst lined with a few cell layers composed of columnar palisading basal cells and a corrugated parakeratin surface. The capsule comprised fibrous connective tissue with variable amounts of blood vessels with hemorrhage, nerve bundles, fat tissue, striated muscle fibers, and the absence of pilosebaceous units. No recurrence was observed after complete surgical removal. All epithelial layers of the 3 cases expressed positivity for CK19 and CD138, the basal cells were positive for Bcl-2 and D2-40, and the superficial epithelial layer was positive for EMA. All cases demonstrated a low proliferation index by Ki-67. Conclusion This study represents a series of 3 cases of STK that affected the posterior buccal mucosa of middle-aged patients from Brazil, sharing histopathological and immunohistochemical features with odontogenic keratocyst.
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... Both gingival cysts and mucoceles arise in similar locations and have similar features; however, the histopathology differs as gingival cysts have thin, noninflamed walls lined by a thin squamous or cuboidal epithelium, and mucoceles have the diagnostic presence of salivary gland tissue and sialomucin (4,10). Epidermoid cyst is another type of keratinised cysts with similar histopathological features; however, previous studies suggested that the differential diagnosis from epidermoid cysts could be done by their immunohistochemical profiles for CK17 and Ki-67 (13). OKC has a strong expression of CK17 and higher Ki-67-labelled cells (11). ...
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... In particular, with the change in terminology from keratocystic odontogenic tumor (KCOT), some clinicians may have lost vigilance when faced with such a probable diagnosis. Several studies [1][2][3] have reported aggressiveness, in which the OKCs were found to penetrate the temporalis or masseter muscle and even the mediastinum. The ability of OKCs to extend into the surrounding tissues significantly impedes entire enucleation, thus leading to imminent recurrence. ...
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To date, few studies have been conducted to test the effectiveness of Carnoy's (CS) versus modified Carnoy's (MC) solution for preventing the recurrence of odontogenic keratocysts, which are potentially aggressive lesions. To evaluate the efficacy of MC application, we conducted a retrospective cohort study over an 18-year period, from October 2004 to October 2022, in 122 patients treated surgically with adjunctive chemical cautery, with either CS (n = 73; median age: 30 years) or MC (n = 49; median age: 42 years), by a single surgeon. The primary outcome variables were observed recurrence and interval to recurrence. Independent variables were demographics, location, clinical presentation at baseline, adjacent tooth extraction, and bone grafting. Males predominated in both groups. No statistically significant differences were observed between the two arms in terms of recurrences in particular months, with six patients (8.2%) in the CS arm and 5 (10.2%) in the MC arm. Of the 11 recurrences, 10 were observed within the first 2 years post-surgery, with only one occurring in the 7th year of follow-up. Thus, when used as adjunctive therapy, the application of MC has an efficiency comparable to that of CS for lowering the recurrence rate of odontogenic keratocysts.
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Immunohistochemical Analysis of Dentigerous Cysts and Odontogenic Keratocysts Associated with Impacted Third Molars—A Systematic Review
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Objective: This systematic review investigates the diagnostic, prognostic, and therapeutic implications of immunohistochemical markers in dentigerous cysts (DCs) and odontogenic keratocysts (OKCs) associated with impacted third molars. Materials and Methods: A comprehensive search strategy was employed across major databases including MEDLINE/PubMed, EMBASE, and Web of Science, from the inception of the databases to March 2024. Keywords and Medical Subject Heading (MeSH) terms such as “dentigerous cysts”, “odontogenic keratocysts”, “immunohistochemistry”, “Ki-67”, and “p53” were used. The PRISMA 2020 guidelines were followed to ensure methodological rigor. Inclusion criteria encompassed studies on humans and animals providing definitive diagnoses or specific signs and symptoms related to DCs and OKCs, with results on protein expression derived from immunohistochemistry, immune antibody, proteomics, or protein expression methods. Results: Of the 159 studies initially identified, 138 met the inclusion criteria. Our analysis highlighted significantly higher expressions of Ki-67 (22.1% ± 4.7 vs. 10.5% ± 3.2, p < 0.001), p53 (15.3% ± 3.6 vs. 5.2% ± 1.9, p < 0.001), and Bcl-2 (18.4% ± 3.2 vs. 8.7% ± 2.4, p < 0.001) in OKCs compared to DCs, indicating a higher proliferative index, increased cellular stress, and enhanced anti-apoptotic mechanisms in OKCs. Additionally, PCNA levels were higher in OKCs (25.6% ± 4.5 vs. 12.3% ± 3.1, p < 0.001). Genetic mutations, particularly in the PTCH1 gene, were frequently observed in OKCs, underscoring their aggressive behavior and potential malignancy. Conclusions: The findings emphasize the significant role of immunohistochemical markers in distinguishing between DCs and OKCs, with elevated levels of Ki-67, p53, Bcl-2, and PCNA in OKCs suggesting a higher potential for growth and recurrence. Genetic insights, including PTCH1 mutations, further support the need for personalized treatment approaches. These markers enhance diagnostic accuracy and inform targeted therapeutic strategies, potentially transforming patient management in oral and maxillofacial surgery.
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Immunohistochemical Analysis of Dentigerous Cysts & Odontogenic Keratocysts Associated with Impacted Third Molars: A Systematic Review
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Full-text available
  • May 2024
Objective: This systematic review investigates the diagnostic, prognostic, and therapeutic implications of immunohistochemical markers in dentigerous cysts (DC) and odontogenic keratocysts (OKC) associated with impacted third molars. Materials and Methods: A comprehensive search strategy was employed across major databases including MEDLINE/PubMed, EMBASE, and Web of Science, from the inception of the databases to March 2024. Keywords and Medical Subject Heading (MeSH) terms such as "dentigerous cysts," "odontogenic kerato-cysts," "immunohistochemistry," "Ki-67," and "p53" were used. The PRISMA 2020 guidelines were followed to ensure methodological rigor. Inclusion criteria encompassed studies on humans and animals providing de-finitive diagnoses or specific signs and symptoms related to DC and OKC, with results on protein expression derived from immunohistochemistry, immune antibody, proteomics, or protein expression methods. Results: Of the 159 studies initially identified, 138 met the inclusion criteria. Our analysis highlighted sig-nificantly higher expressions of Ki-67 (22.1% ± 4.7 vs. 10.5% ± 3.2, p < 0.001), p53 (15.3% ± 3.6 vs. 5.2% ± 1.9, p < 0.001), and Bcl-2 (18.4% ± 3.2 vs. 8.7% ± 2.4, p < 0.001) in OKCs compared to DCs, indicating a higher proliferative index, increased cellular stress, and enhanced anti-apoptotic mechanisms in OKCs. Ad-ditionally, PCNA levels were higher in OKCs (25.6% ± 4.5 vs. 12.3% ± 3.1, p < 0.001). Genetic mutations, particularly in the PTCH1 gene, were frequently observed in OKCs, underscoring their aggressive behavior and potential malignancy. Conclusion: The findings emphasize the significant role of immunohistochemical markers in distinguishing between DCs and OKCs, with elevated levels of Ki-67, p53, Bcl-2, and PCNA in OKCs suggesting a higher potential for growth and recurrence. Genetic insights, including PTCH1 mutations, further support the need for personalized treatment approaches. These markers enhance diagnostic accuracy and inform targeted thera-peutic strategies, potentially transforming patient management in oral and maxillofacial surgery.
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Primary odontogenic keratocyst in the cheek muscles: Report of the 4th case in the world and review of peripheral OKC literature
Article
  • Apr 2023
Introduction and importance: Odontogenic keratocyst (OKC) is a developmental odontogenic cyst that usually can be seen within the jaw bones. The cyst arises from the remnants of odontogenic epithelial cells in the jaw bones. In rare cases the cyst can arise in the extraosseous tissues like the gingiva which is the most common site. However, other uncommon sites like oral mucosa and orofacial muscles have been reported. Case presentation: In this article we present a case report of 17-years-old male patient who visited the dentist complaining of a swelling in the right cheek for almost 2 years. He had no medical history with medications or genetic diseases. The mass was removed by the oral surgeon then subjected to histological examination; it was found to be an intramuscular odontogenic keratocyst. Clinical discussion: Intramuscular odontogenic keratocyst is a rare cyst that can be seen in the orofacial muscle, and it can be difficult to diagnose when only clinical and radiographic features are based, and the definitive diagnosis is based on histological examination. The treatment is complete surgical excision. Conclusions: 39 cases were reported and achieved since 1971 until now, most of them presented in the gingiva and buccal mucosa and extremely rare within the muscles.
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The extra-osseous odontogenic keratocyst: An anachronism?
Article
  • Jul 2022
Introduction The aim of this study was to review the literature on extra-osseous odontogenic keratocysts, and to present the best possible approach to these lesions. Material and methods A comprehensive literature search was performed using the strategy: (keratocyst) and (soft tissue)). A total of 25 articles were included, 20 reported on extra-osseous odontogenic keratocysts in the soft tissues of the mouth and 17 presented as gingiva cysts. Discussion Almost all articles were published in the last 20 years and 16 even in the last 10 years. Extra-osseus odontogenic keratocysts are usually found in the cheek or present as gingiva cysts of adults. Muscle abutment of the cheek lesions is common but infiltration of muscles has also been reported. Conclusion In almost none of the reported cases was a preoperative diagnosis available. Based on the clinical presentation and available laboratory tests it is suggested to always do an aspiration biopsy to ascertain the diagnosis preoperatively. This is particularly relevant for those who appear in the soft tissues of the mouth.
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A case of a lesion of the cheek histopathologically resembling keratocystic odontogenic tumor
Article
  • Jan 2008
We encountered a lesion of the cheek resembling keratocystic odontogenic tumor (KCOT). The lesion measured 30×28mm and was located in the soft tissue of the left cheek, below the parotid papilla. On H-E staining, this lesion histopathologically resembled KCOT of the jaw. Therefore, we examined the expressions of Ki-67 and cytokeratin 17 antigen immunohistochemically. The Ki-67 labeling index in this lesion indicated high cell proliferation (17.1%), and the localization of Ki-67-positive cells and CK17-stained cells mimicked typical KCOT of the jaw. On the basis of these findings, we diagnosed a lesion of the cheek resembling KCOT.
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Odontogenic Keratocyst, Orthokeratinized Odontogenic Cyst and Epidermal Cyst: An Immunohistochemical Study Including Markers of Proliferation, Cytokeratin and Apoptosis Related Factors
Article
  • Jan 2004
Objective: There are microscopic similarities among odontogenic keratocyst (OKC), orthokeratinized odontogenic keratocyst (OOC) and epidermal cyst (EDC). This study was to compare with cell proliferation, cell differentiation and apoptosis related factors in OKC, OOC and EDC in order to clarify the characters and category of three hitstopathologically similar cysts.Material and Methods: Fourteen cases of OKC, nine cases of OOC and eighteen cases of EDC were examined immunohistochemically using antibodies against Ki-67, cytokeratins (CK7, 10, 10/13, 17, 18, 19, 20) and apoptosis related factors (bcl-2 and Bax).Results: Ki-67 labeling index in OKC was statistically higher than that in OOC and EDC (p<0.05). And that in OOC was higher in EDC (p<0.05). In OKC, CKs and bcl-2 expression patterns were different from OOC and EDC, while both OOC and EDC showed similar reactivity with CKs and bcl-2.Conclusions: The present results suggested that OKC had high cellular proliferation and was relatively low differentiation as compare with OOC and EDC. In addition, there was participation of apoptosis suppressor in OKC. The character of OOC occupied an intermediate position between OKC and EDC. Therefore, it was possible to consider OOC as a distinct entity from OKC. EDC had the lowest cellular activity in the three cysts and it was comparatively maturated lesion.
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Infrequent clinicopathologic features of keratocystic odontogenic tumour: A 29-year multi-institutional retrospective review
Article
  • Feb 2009
Aim: Keratocystic odontogenic tumour (KCOT), formerly known as odontogenic keratocyst, is an interesting and challenging entity. This study addresses the spectrum of clinicopathologic features of KCOT other than those classically described. Materials and methods: Three hundred forty‐seven cases of KCOT from the records of three institutions over a period of 29 years were retrospectively reviewed to analyse their clinical presentation, radiographic features, histopathology and biological behaviour. Results: Six cases of KCOT with infrequent findings were retrieved, none of which was associated with the nevoid basal cell carcinoma syndrome. Two lesions gave an erroneous radiographic impression of radicular cyst and nasopalatine duct cyst, respectively; the former periapical KCOT showed recurrence. An additional small KCOT adjacent to the initially presenting lesion was incidentally discovered, and both periradicular KCOT recurred twice. In interradicular KCOT, the growth rate of 2.4 mm per year was successfully estimated on radiographs. One paediatric KCOT showed a deceptive feature of eruption cyst and recurrence was not evident, despite of the fenestration. Microscopic rarities included mural cartilaginous metaplasia in a recurrent periradicular KCOT. Conclusions: This series of cases substantiates the preceding observations that KCOT has a reputation for clinically confusing jaw lesions, often resulting in a potential endodontic or periodontal misdiagnosis. Believed to exhibit occasional recurrent behaviour, missing a diagnosis of KCOT has serious implications for the patient. Both in principle and in practice, the differential diagnosis of KCOT deserves consideration in non‐healing radiolucencies associated with the roots of teeth.
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The Odontogenic Keratocyst: A Cyst, or a Cystic Neoplasm?
Article
  • Feb 2011
  • J DENT RES
The odontogenic keratocyst (OKC, currently designated by the World Health Organization as a keratocystic odontogenic tumor) is a locally aggressive, cystic jaw lesion with a putative high growth potential and a propensity for recurrence. Although it is generally agreed that some features of OKCs are those of a neoplasia, notably the relatively high proliferative rate of epithelial cells, controversies over the behavior and management of OKCs still exist. This article is intended to review this intriguing entity and to summarize the findings of recent studies related to the nature of OKCs and their clinical and therapeutic implications. Recent advances in genetic and molecular research, i.e., PTCH1 mutations and involvement of the Hedgehog signaling pathway, have led to increased knowledge of OKC pathogenesis which hints at potential new treatment options, although the question of whether the OKC is a cyst or a cystic neoplasm is yet to be answered with certainty. Since some advocate a more conservative treatment for OKCs, notably marsupialization and decompression, future treatment strategies may focus on molecular approaches and eventually reduce or eliminate the need for aggressive surgeries.
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Keratocyst of the buccal mucosa: Is it odontogenic?
Article
  • Nov 2010
Odontogenic keratocyst (OKC) of the buccal mucosa, the diagnosis of which is based on subjective histologic evaluation, is a controversial entity of questionable existence. This report describes 2 rare cases of parakeratinized cyst arising from the buccal mucosa. Case 1 was a 60-year-old man with a 3-cm cyst and case 2 was a 16-year-old boy with a microcyst incidentally discovered on histology. Both lesions were essentially identical in histologic appearance and immunophenotype to intraosseous and gingival OKC, but they were clearly different from orthokeratinized odontogenic cysts and buccal mucosal epidermoid cysts. Step sections failed to reveal any kind of odontogenic tissue or skin adnexa in the cyst wall. These microscopic characteristics reflexively lead to the diagnosis of OKC, if the extragingival occurrence in the buccal mucosa cannot be considered. An alternative nonodontogenic origin includes a keratocyst of the skin, ie, an unusual mucosal presentation of cutaneous keratocyst. Because its true nature, either odontogenic or epidermal, cannot be conclusively proven at this time, we propose a more descriptive and noncommittal term, "mucosal keratocyst," for a particular cyst in a buccal location that is morphologically indistinguishable from OKC.
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Case report of extragingival peripheral ameloblastoma in buccal mucosa
Article
  • Oct 2009
A peripheral ameloblastoma (PA) is a rare variant of ameloblastoma that generally occurs in the extraosseous region; an extragingival PA is extremely rare. There have been 5 cases reported of a PA occurring in the buccal mucosa and 1 in the oral floor. We present the sixth known case of extragingival PA in the buccal mucosa, which occurred in an 88-year-old woman.
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An ectopic odontome in the cheek
Article
  • May 1977
  • Oral Surg Oral Med Oral Pathol
A 9-year-old girl had an ectopic odontome located in soft tissue alone. The mass was excised with no ill effect; there was no evidence of true tumor.
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Cutaneous keratocysts of nevoid basal cell carcinoma syndrome
Article
  • May 1986
  • J AM ACAD DERMATOL
Four cysts were removed from two unrelated patients with nevoid basal cell carcinoma syndrome. Multiple sections from each cyst were studied. Two cysts showed histologic features similar to keratocysts that occur in the jaws of patients with this syndrome. The cysts were lined by a festooned epithelium consisting of two to five layers of squamous cells that formed keratin without the presence of a granular cell layer. One cyst contained some lanugo hair and a small bud of follicular epithelium. This cyst was therefore similar to cutaneous steatocysts but did not have an identifiable sebaceous component. The second cyst was devoid of hair and adnexal structures and was indistinguishable from a jaw keratocyst. Two other cysts were typical epidermoid (infundibular) cysts. Although speculative, it is likely that some cutaneous cysts in patients with nevoid basal cell carcinoma syndrome are identical to jaw keratocysts and may be another cutaneous marker for this disease complex.
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