Leiomyoma is the most common neoplasm of the female
genital tract and conventional leiomyomas are usually easy to
diagnose. Some variant forms with unusual infiltrative growth
pattern have been known including intravenous leiomyomato-
sis, leiomyoma with vascular invasion, diffuse leiomyomatosis,
and disseminated peritoneal leiomyomatosis (1). Recently,
cotyledonoid dissecting leiomyoma was proposed for a new
form of uterine leiomyoma with histologically benign, but
distinctive gross features resembling cotyledon of the placenta
(2). It is indicated to perform frozen sections because of the
sarcomatoid operative appearance of the lesion. The recognition
of this condition by surgeons and pathologists will prevent
radical hysterectomy and preserve fertility in young female
patients. This report describes a case of cotyledonoid dissecting
leiomyoma of the uterus, comparing the gross, microscopic,
immunohistochemical, and ultrastructural findings of the lesion
with those of previously reported cases.
A 26-yr-old nulliparous woman presented with an uterine
mass, incidentally detected on ultrasound examination for the
confirmation of pregnancy, associated with a recent onset of
vaginal bleeding. Her pregnancy was terminated by sponta-
neous abortion 2 months before admission. Ultrasonogram and
pelvic magnetic resonance imaging (MRI) showed a large, 12-
cm sized, irregular contoured mass in the left lateral aspect of
the uterus, which was presumed to be a subserosal leiomyoma
(Fig. 1). She underwent laparotomy for the huge pelvic mass.
At operation, there were numerous exophytic congested small
nodules, resembling placental cotyledons, extending from the
uterine wall posteriorly into the left broad ligament and pelvic
cavity, as well as two small typical intramural leiomyomas, one
of which seemed to be in continuity with the extrauterine
lesion. An operative impression of sarcoma by surgeon turned
out to be a histologically benign smooth muscle tumor based
on frozen section. The extrauterine component was incomplete-
lyresected to save the uterus.
The specimen consisted of innumerable fragments of nod-
ules weighing up to 150.0 g. The nodules were rubbery
reddish and solid, ranging from 0.5 to 5.5 cm in diameter,
and these nodules were closely packed and connected by thin
fibrous tissue containing engorged vasculature (Fig. 2). Micro-
scopically, the tumor showed variable sized micronodules of
muscle fascicles, which were separated by fibrous connective
tissue with a marked hydropic change and rich vascularity,
resulting in a multinodular appearance (Fig. 3). The fascicles
of smooth muscle cells showed not only the ordinary features
of leiomyoma but also a disorganized, swirled appearance with
slightly enlarged nuclei. There were neither significant nuclear
atypia nor mitotic figures. No coagulative tumor cell necrosis
Mi-Jin Kim, Yoon-Ki Park*, Jae-Ho Cho
Department of Pathology, Obstetrics and
Gynecology*, and Radiology
University College of Medicine, Daegu, Korea
Address for correspondence
Mi-Jin Kim, M.D.
Department of Pathology, Yeungnam University
College of Medicine, 317-1 Daemyung-dong,
Nam-gu, Daegu 705-717, Korea
Tel : +82-53-620-3334, Fax : 82-53-656-1429
E-mail : email@example.com
J Korean Med Sci 2002; 17: 840-4
Copyright � The Korean Academy
of Medical Sciences
Cotyledonoid Dissecting Leiomyoma of the Uterus
: A Case Report and Review of the Literature
“Cotyledonoid dissecting leiomyoma” or “Sternberg tumor” is a very rare variant of
smooth muscle tumors with a distinctive gross appearance. We describe a similar
lesion, probably the sixth reported case, comparing its clinicopathological features
with those of previous cases. A 26-yr-old nulliparous woman underwent laparo-
tomy for a large pelvic mass replacing the postero-lateral aspect of the uterus with
extension into the left pelvic cavity in the form of numerous exophytic congested
small nodules. The tumor was removed by resection without hysterectomy after
frozen section examination. Histologically, there were variable sized micronodules
of benign smooth muscle fascicles, which were separated by fibrous connective
tissue with a marked hydropic change and rich vascularity. Immunohistochemical
and ultrastructural studies were helpful for confirmation of the smooth muscle nature,
but not useful for the definitive diagnosis. Due to bizarre, sarcoma-like gross appear-
ances, this type of lesion should be subjected to frozen section examination in order
to avoid overtreatment and preserve the fertility in young women.
Key Words : Uterus; Leiomyoma; Frozen Sections; Immunohistochemistry; Microscopy, Electron
Received : 28 August 2001
Accepted : 18 December 2001
was observed (Fig. 4). Masson’s trichrome and elastic stains
revealed accentuated proliferation of muscular and non-mus-
cularvessels in the fibrous connective tissue between muscle
fascicles and its covering as well as prominent nodularity (Fig.
5).The patient was well with no recurrent disease at 2 yr after
Immunohistochemically, the tumor showed a strong staining
for both desmin and muscle-specific actin. Factor VIII-relat-
ed antigen was positive in the endothelial cells of the blood
vessels, with no evidence of intravascular growth of the tumor
(Fig. 6). Vimentin was positive in intervening fibrous septa
including blood vessel walls and was only focally positive in the
Cotyledonoid Dissecting Leiomyoma
Fig. 1. Pelvic MRI shows an exophytic heterogeneous mass lesion
with low signal intensity in the left pelvic cavity as well as a small
homogeneous intramural leiomyoma (arrow) in the uterine fundus.
Fig. 2. Gross appearance of the resected exophytic mass shows
innumerable congested, bulbous (cotyledonoid) nodules, vary-
ing from 0.5 to 5.5 cm in their greatest dimension.
Fig. 3. The tumor is composed of nodules of smooth muscle fas-
cicles separated by hydropic connective tissue containing con-
gested vessels (H&E stain, ×40).
Fig. 4. The tumor cells show a swirled fascicular growth pattern
with slightly enlarged nuclei. Significant cellular atypia, mitoses or
necrosis are not present (H&E stain, ×200).
tumor cells. Ultrastructurally, the tumor cells had elongated
nuclei and myofilaments with dense plaque in their cytoplasm
that can be seen in usual leiomyoma (Fig. 7).
Cotyledonoid dissecting leiomyoma was initially described
by Roth et al. (2) in 1996. They reported four cases of an unusu-
al form of leiomyoma, naming it “cotyledonoid dissecting
leiomyoma” due to its gross similarity with placental cotyle-
dons. It could also be called “Sternberg tumor” because their
study was dedicated to the late Dr. William H Sternberg who
had originally studied the tumor as “a red seaweed lesion”.
Recently, an additional case of cotyledonoid dissecting leiomy-
omawas subsequently reported by Menolascino-Bratta et al.
(3), who preferred to call this tumor “angionodular dissecting
In the report by Roth et al. (2), the age range of the patients
was 23-41 yr. All patients had a pelvic mass or an enlarged
uterus. Menolascino-Bratta’s case was a 26-yr-old woman with
colic abdominal pain due to acute appedicitis. In the case de-
scribed here, the mass was incidentally detected on ultrasound
examination in a 26-yr-old nulliparous woman. The patient
reported by Menolascino-Bratta et al. (3) also had preoperative
ultrasonogram, which suggested leiomyomatosis. All patients
were treated by hysterectomy, except one of Roth’s series who
underwent partial resection of the uterus with excision of the
tumor. Our patient also underwent resection of exophytic mass
with consequent preservation of the uterus, according to the
frozen sections that demonstrated a histologically benign
smooth muscle tumor. This is the first reported case in which
a frozen section was taken.
In the previous reports, the tumor size ranged 10-25 cm.
M.-J. Kim, Y.-K. Park, J.-H. Cho
Fig. 5. Cotyledonoid processes show proliferation of both round
thick-walled muscular and dilated thin-walled non-muscular ves-
sels in the fibrous connective tissue between muscle fascicles
and covering the process (elastic stain, ×100).
Fig. 7. Electron micrograph of the tumor cells shows elongated
nuclei and cytoplasms packed with myofilaments with dense
plaques (arrows). Intermediate junctions (arrowheads) on the
plasma membrane are also seen (×3,000).
Fig. 6. Immunohistochemical stains. (A) desmin is positive in mus-
cle fibers (×40). (B) Factor VIII shows marked proliferating vessels
without intravascular growth (×40).
The tumor was on the right side in two patients, left side in
two, and bilateral in one in which the smaller measured 3.2 cm
in maximum dimension. In all cases, the exophytic component
was in continuity with a lobulated, multinodular myometrial
tumor with an irregular border. Typical intramural leiomy-
omas were identified in two cases. Gross findings of the present
case were similar to those previously described and illustrated,
although only the extrauterine component was examined.
Microscopically, Roth et al. described that the main tumor
growing in dissecting pattern in the intrauterine component
and cotyledonoid extrauterine extension was composed of
variable sized micronodules of muscle fascicles with a marked
hydropic change and rich vascularity. The case documented
herein confirmed this observation, although details of the
microscopic pictures of the myometrial component of the
tumor remain unknown. Whereas all other cases reported had
thin-walled, dilated, and congested vessels in the extrauterine
nodules and round, muscular, and sometimes hyalinized ves-
sels in the intramural portion, our case showed both round,
thick-walled muscular and dilated, thin-walled non-muscular
vessels in the extrauterine component, without evidence of
hyalinization of the vessel walls. The vascular proliferation was
more prominent in the fibrous septa than within the fascicles
of smooth muscle.
Menolascino-Bratta et al. (3) noticed that immunohisto-
chemical and ultrastructural studies were not useful for the
diagnosis. Our case also showed that those ancillary techniques
were not useful in evaluation of the tumor outside of the con-
firmation of smooth muscle nature. The whorling, disorga-
nizedmyofilaments observed ultrastructurally in Menolascino-
Bratta’s case were not observed in the present case.
Roth’s patients were followed for up to 41 yr and none had
experienced recurrence, and Menolascino-Bratta’s patient had
been asymptomatic for 1 yr. In our case, the patient has been
well without recurrent disease 2 yr after operation.
In 1997, Kiaer (4) and Honore (5) pointed out the similar-
ity of these tumors to “grapelike” leiomyoma of the uterus (6)
and suggested that these tumors including those in Roth’s
series, if not identical, are very closely related variants of an
extremely rare form of uterine leiomyoma. To our knowledge,
another case reported in 1998 (7) was similar in part to these
lesions. Unlike other reports, they performed DNA flow cyto-
metricstudy, which revealed diploid, benign nature.
Differential diagnosis includes intravenous leiomyomatosis,
and leiomyoma with perinodular hydropic change. Although
intravenous leiomyomatosis may be grossly multinodular and
may involve broad ligament (8), the exophytic component
is not congested and intravascular growth is characteristic.
Multinodularity of the intrauterine component and hydropic
changes in connective tissue are features of both cotyledonoid
dissecting leiomyomas and some leiomyomas with perinodular
hydropic degeneration (9), but leiomyomas with multinodular
hydropic degeneration show usual pattern of leiomyoma lack-
ing distinctive gross features seen in cotyledonoid dissecting
In summary of the reported cases, the tumor seems to have
a “cotyledonoid” or “grapelike” gross appearance of the ex-
trauterine nodules and “dissecting” infiltrative growth pattern
in the intrauterine component under microscope. Recently,
Roth and Reed (10) described a case of ‘cotyledonoid leiomy-
oma’ without an intrauterine component. They stated that
the tumor was different from the cotyledonoid dissecting
leiomyoma and represented another variant of benign uterine
smooth muscle tumors with unusual growth patterns. Any-
way, at present, it is mandatory to unify the terminology
indicating this unique variant of leiomyoma. Further accu-
mulation of information on these tumors under the name of
“cotyledonoid” dissecting leiomyoma will contribute to elu-
cidatethe nature of the tumor.
1. Clement PB. Pure mesenchymal tumors. In: Tumor and tumor-like
lesions of the uterine corpus and cervix, New York: Churchill Living-
stone, 1993: 265-74.
2. Roth LM, Reed RJ, Sternberg WH. Cotyledonoid dissecting leiomy-
oma of the uterus: the Sternberg tumor. Am J Surg Pathol 1996; 20:
3. Menolascino-Brrata F, Garcia de Barriola V, Navajo de Gomez M,
Garcia Tamayo J, Suarez JA, Hernandez Chacon AV. Cotyledonoid
dissecting leiomyoma (Sternberg tumor): an unusual form of leiomy-
oma. Pathol Res Pract 1999; 195: 435-8.
4. Kiaer H. Is cotyledonoid dissecting leiomyoma of the uterus (Sternberg
tumor) identical with grape-like leiomyoma of the uterus? [letter] Am
J Surg Pathol 1997; 21: 1257-8.
Cotyledonoid Dissecting Leiomyoma
Roth’s seriesCase 1
AUB, pelvic mass
Presentation Size (cm)
Table 1. Summary of clinico-pathologic features of cases of cotyledonoid dissecting leiomyoma
AUB, abnormal uterine bleeding; TAH-BSO, total abdominal hysterectomy-bilateral salpingo-oophorectomy; TVH, total vaginal hysterectomy
5. Honore LH. Is cotyledonoid dissecting leiomyoma of the uterus (Stern-
berg tumor) identical with grape-like leiomyoma of the uterus? [letter]
Am J Surg Pathol 1997; 21: 1257-8.
6. David MP, Hommonnai TZ, Deligdish L, Lowenthal M. Grape-like
leiomyomas of the uterus. Int Surg 1975; 60: 238-9.
7. Fukunaga M, Ushigome S. Dissecting leiomyoma of the uterus with
extrauterine extension. Histopathology 1998; 32: 160-4.
8. Clement PB, Young RH, Scully RE. Intravenous leiomyomatosis of the
uterus. A clinicopathological analysis of 16 cases with unusual histologic
features. Am J Surg Pathol 1988; 12: 932-45.
9. Clement PB, Young RH, Scully RE. Diffuse, perinodular and other
patterns of hydropic degeneration within and adjacent to uterine leiomy-
omas.Problems in differential diagnosis. Am J Surg Pathol 1992; 16:
10. Roth LM, Reed RJ. Cotyledonoid leiomyoma of the uterus: report of
a case. Int J Gynecol Pathol 2000; 19: 272-5.
M.-J. Kim, Y.-K. Park, J.-H. Cho