Mai P Hoang

Harvard Medical School, Boston, Massachusetts, United States

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Publications (123)539 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BAP1 (BRCA1-Associated Protein 1) is a tumor suppressor gene whose mutations have recently been reported to increase susceptibility for the development of uveal melanoma, cutaneous atypical and epithelioid melanocytic lesions, clear cell renal cell carcinoma and other tumors. Screening for BAP1 mutation/loss/inactivation and BRAFV600E mutation can be done by immunohistochemistry. We investigated BAP1 and BRAFV600E expression in 193 sporadic melanocytic lesions (11 dermal nevi, 20 congenital nevi, 40 primary and non-desmoplastic melanomas, 40 desmoplastic melanomas, 23 metastatic melanomas, 17 Spitz nevi, 19 atypical Spitz nevi, 8 atypical Spitz tumors, 14 proliferative nodules arising in congenital nevi, 1 nevus during pregnancy), and 30 melanocytic lesions from 3 patients with family history of uveal melanoma and BAP1 germline mutation. Most sporadic melanocytic lesions exhibited positive BAP1 nuclear staining except for 1 proliferative nodule arising in congenital nevus; 1 desmoplastic, 1 nevoid and 2 metastatic melanomas. BRAFV600E positivity was demonstrated in 80% of dermal, 5% of congenital, 6% of Spitz, and 5.5% of atypical Spitz nevi; 29% of proliferative nodules arising in congenital nevi; 24% of primary and non-desmoplastic and 35% of metastatic melanomas. Combined BAP1 loss and BRAFV600E staining was seen in 67% of BAP1 tumor syndrome-associated lesions and in none of the sporadic melanocytic proliferations including Spitz and atypical Spitz nevi and atypical Spitz tumors, with the exception of 1 primary melanoma. The combined BAP1-BRAFV600E + immunoprofile appears to be a constant feature of BAP1 tumor syndrome-associated melanocytic lesions, and the designation of Spitz nevi or variants thereof appears to be inaccurate for this group of lesions.
    Human pathology 11/2014; · 3.03 Impact Factor
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    ABSTRACT: The management of dysplastic nevi (DN) is a highly debated and controversial topic within the dermatology community. Clinicians agree that margin-positive severely DN should be removed with a surgical margin, however, there is disagreement surrounding the appropriate management of margin-positive mildly and moderately DN.
    Journal of the American Academy of Dermatology 09/2014; · 4.91 Impact Factor
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    ABSTRACT: : Currently, urogenital complaints are among the most common problems encountered by family practitioners, gynecologists, and dermatologists. In response to the intricacy of vulvar disorders, the International Society for the Study of Vulvovaginal Disease was created to facilitate the exchange between clinicians and pathologists involved in the care of these patients. Recent classifications for inflammatory disorders and intraepithelial neoplasm have been proposed. In addition, vulvar skin biopsies are the most common source of intradepartmental consultation during dermatopathology sign-out. The purpose of this article is to review the various inflammatory dermatoses of the vulva and to update readers with new advances regarding these entities.
    The American Journal of dermatopathology. 09/2014; 36(9):689-704.
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    ABSTRACT: The VE1 monoclonal antibody was developed to recognize the V600E mutation in BRAF, which is found in various tumors.
    American Journal of Clinical Pathology 06/2014; 141(6):811-5. · 2.88 Impact Factor
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    ABSTRACT: Melanoma is an invasive malignancy with a high frequency of blood-borne metastases, but circulating tumor cells (CTCs) have not been readily isolated. We adapted microfluidic CTC capture to a tamoxifen-driven B-RAF/PTEN mouse melanoma model. CTCs were detected in all tumor-bearing mice and rapidly declined after B-RAF inhibitor treatment. CTCs were shed early from localized tumors, and a short course of B-RAF inhibition following surgical resection was sufficient to dramatically suppress distant metastases. The large number of CTCs in melanoma-bearing mice enabled a comparison of RNA-sequencing profiles with matched primary tumors. A mouse melanoma CTC-derived signature correlated with invasiveness and cellular motility in human melanoma. CTCs were detected in smaller numbers in patients with metastatic melanoma and declined with successful B-RAF-targeted therapy. Together, the capture and molecular characterization of CTCs provide insight into the hematogenous spread of melanoma.
    Cell Reports 04/2014; · 7.21 Impact Factor
  • JAMA dermatology. 01/2014;
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    ABSTRACT: Craniopharyngiomas are epithelial tumors that typically arise in the suprasellar region of the brain. Patients experience substantial clinical sequelae from both extension of the tumors and therapeutic interventions that damage the optic chiasm, the pituitary stalk and the hypothalamic area. Using whole-exome sequencing, we identified mutations in CTNNB1 (β-catenin) in nearly all adamantinomatous craniopharyngiomas examined (11/12, 92%) and recurrent mutations in BRAF (resulting in p.Val600Glu) in all papillary craniopharyngiomas (3/3, 100%). Targeted genotyping revealed BRAF p.Val600Glu in 95% of papillary craniopharyngiomas (36 of 39 tumors) and mutation of CTNNB1 in 96% of adamantinomatous craniopharyngiomas (51 of 53 tumors). The CTNNB1 and BRAF mutations were clonal in each tumor subtype, and we detected no other recurrent mutations or genomic aberrations in either subtype. Adamantinomatous and papillary craniopharyngiomas harbor mutations that are mutually exclusive and clonal. These findings have important implications for the diagnosis and treatment of these neoplasms.
    Nature Genetics 01/2014; · 35.21 Impact Factor
  • Julie Y Tse, Mai P Hoang
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    ABSTRACT: Adnexal tumors are often benign, rarely malignant, and in some settings they can be associated with a hereditary syndrome that predisposes to visceral malignancies. This article aims to review and update the various genetic syndromes that are characterized by cutaneous appendage neoplasms. Some are of clinical importance due to the association with internal malignancy, and they include Cowden, Gardner, Birt–Hogg–Dubé, Muir–Torre, basal cell nevus and Brooke–Spiegler syndromes. Others are not associated with internal malignancy, such as multiple familial trichoepithelioma, generalized basaloid follicular hamartoma, Bazex–Dupré–Christol, Rombo, Oley and steatocystoma multiplex syndromes. Awareness that some adnexal neoplasms are clues to internal malignancies might allow for early diagnosis, genetic counseling and appropriate cancer surveillance.
    Expert Review of Dermatology 01/2014; 7(3).
  • Journal of the European Academy of Dermatology and Venereology 01/2014; · 2.69 Impact Factor
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    ABSTRACT: The histopathologic distinction between primary adnexal carcinomas and metastatic adenocarcinoma to the skin from sites such as the breast, lung, and others often presents a diagnostic dilemma. Current markers of diagnostic utility include p63 and cytokeratin 5/6; however, their expression has been demonstrated in 11%-22% and 27% of cutaneous metastases, respectively. Furthermore, the immunoreactivity of p40 and GATA3 in various cutaneous adnexal carcinomas has not been previously reported. In the present study, we compared the expression of p40, p63, cytokeratin 5/6, and GATA3 in a total of 143 cases, including 67 primary adnexal carcinomas and 76 cutaneous metastases. p40, p63, cytokeratin 5/6, and GATA3 expression was observed in 80%, 84%, 86% and 47% of primary adnexal carcinoma, respectively; and in 8%, 17%, 26% and 40% of cutaneous metastases, respectively. Chi-square analysis revealed statistically significant p-values (<0.0001) for p40, p63, and cytokeratin 5/6 in distinguishing primary adnexal carcinoma from cutaneous metastases. In summary, while p63 and cytokeratin 5/6 have similar sensitivity (84% and 86%, respectively) in detecting primary adnexal carcinomas, p40 appeared to be the most specific marker (92%) with the best positive predictive value (90%). Since breast and lung are the most common sites of origin for cutaneous metastases, p40 is the best distinguishing marker in these settings. None of the four studied markers (p40, p63, cytokeratin 5/6, and GATA3) are helpful in distinguishing between primary adnexal carcinomas from cutaneous metastases of salivary gland or bladder malignancies.
    Human pathology 01/2014; · 3.03 Impact Factor
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    ABSTRACT: Often the distinction of cutaneous apocrine carcinoma from metastatic mammary apocrine carcinoma to the skin can be a diagnostic dilemma because both tumors share similar histologic features and have overlapping immunohistochemical profile. We compared the expression of adipophilin, cytokeratin 5/6, p63, GATA3, mammaglobin, androgen receptor, estrogen receptor, progesterone receptor, and HER2 by immunohistochemistry in 14 cutaneous apocrine carcinomas (11 primary tumors, 3 metastases) and 26 primary apocrine carcinomas of the breast. Whereas focal adipophilin staining was seen in 36% (5/14) of cutaneous apocrine carcinoma, strong and diffuse adipophilin staining was seen in 88% (22/25) of mammary apocrine carcinoma (P = .0013). Differences in estrogen receptor and progesterone receptor expression were also statistically significant (P = .018 and .043). Androgen receptor was strongly positive in all cutaneous and mammary cases. Although there was no significant difference in the frequency of expression of cytokeratin 5/6, p63, HER2, GATA3, and mammaglobin in cutaneous apocrine carcinoma versus mammary apocrine carcinoma, strong and diffuse cytokeratin 5/6 and/or mammaglobin expression were seen only in cutaneous apocrine carcinoma. In conclusion, cutaneous apocrine carcinoma is likely adipophilin- ER+ PR+/- HER2- and can exhibit strong and diffuse cytokeratin 5/6 and/or mammaglobin expression. On the contrary, a mammary apocrine carcinoma is likely adipophilin+ ER- PR- and often exhibit 3+ HER2 with corresponding HER2 gene amplification. A panel of adipophilin, ER, PR, HER2, cytokeratin 5/6, and mammaglobin may be helpful in distinguishing cutaneous apocrine carcinoma from mammary apocrine carcinoma.
    Human pathology 12/2013; · 3.03 Impact Factor
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    ABSTRACT: BRAF mutation is seen in a variety of human neoplasms including cutaneous malignant melanoma, papillary thyroid carcinoma, colorectal carcinoma, non-small cell lung carcinoma, pleomorphic xanthoastrocytoma, and others. Currently, there are 2 commercially available monoclonal antibodies for the detection of BRAF V600E mutation; however, a full and practical comparison of their performance in various tumor types on an automated staining platform has not been done. We investigated their sensitivity and specificity in detecting the BRAF V600E mutation in a series of 152 tumors including 31 malignant melanomas, 25 lung carcinomas, 32 gastrointestinal carcinomas, 23 thyroid carcinomas, 35 gliomas, and 6 other malignancies. In this series, the concordance rate between immunohistochemistry (IHC) and mutational analyses was 97% (148/152) for VE1 and 88% (131/149) for anti-B-Raf. The sensitivity and specificity were 98% (60/61) and 97% (88/91) for monoclonal VE1 and 95% (58/61) and 83% (73/88) for anti-B-Raf, respectively. There were 4 cases with discordant IHC and mutational results for monoclonal VE1 in contrast to 18 cases for anti-B-Raf. Our studies showed that IHC with monoclonal VE1 has a better performance compared with anti-B-Raf in an automated staining platform and confirmed that clone VE1 provides excellent sensitivity and specificity for detecting the BRAF V600E mutation in a variety of tumor types in a clinical setting.
    Human pathology 09/2013; · 3.03 Impact Factor
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    ABSTRACT: Context.-Because the skin and modified mucosal surfaces of the vulvar region contain dense apocrine glands and anogenital mammary-like glands, in addition to eccrine glands and folliculosebaceous units, benign as well as malignant lesions derived from these adnexal structures are, not surprisingly, found in the vulva. However, their incidence occurring in the vulva has not been reported, to our knowledge. Objective.-To determine the incidence of various vulvar adnexal lesions. Design.-We performed a retrospective review (1978-2010) of the cases at our institution. Results.-A total of 189 vulvar adnexal lesions were identified. Most of these lesions were benign (133 of 189; 70%), with hidradenoma papilliferum being the most common, followed by syringoma and various types of cysts. Rare cases of tubular adenoma, poroma, spiradenoma, hidradenoma, cylindroma, sebaceoma, and trichoepithelioma were identified. Malignant adnexal neoplasms comprised the remaining 30% (56 of 189) of the cases. Extramammary Paget disease was the most common (49 of 56), and 29% (14 of 49) demonstrated an invasive component. Rare cases of basal cell carcinoma, sebaceous carcinoma, apocrine carcinoma, adenoid cystic carcinoma, and spiradenocarcinoma were identified. Conclusions.-In this retrospective review, we identified several benign entities that have not been previously reported on the vulva, namely pilomatricoma, poroma, spiradenoma, and sebaceoma. Hidradenoma papilliferum and extramammary Paget disease were the most common benign and malignant adnexal neoplasms, respectively. The spectrum of various vulvar adnexal lesions appears to reflect the frequency of the underlying glandular elements.
    Archives of pathology & laboratory medicine 09/2013; 137(9):1237-46. · 2.78 Impact Factor
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    ABSTRACT: Although adipophilin has been reported to be a sensitive marker for sebaceous carcinoma, others have noted its expression in squamous cell carcinoma and a variety of noncutaneous tumors, suggesting that lipid droplet accumulation is a frequent feature of neoplastic cells. We investigated the expression of adipophilin and perilipin in 101 cutaneous carcinomas. They included 30 cases of sebaceous carcinoma, 28 squamous cell carcinoma with clear cell change (18 invasive and 10 in situ tumors), 8 hidradenocarcinomas, 1 spiradenocarcinoma, 10 porocarcinomas, 4 malignant chondroid syringomas, 1 malignant cylindroma, 7 apocrine carcinomas, 6 eccrine carcinomas, 5 aggressive digital papillary adenocarcinomas, and 1 pilomatrical carcinoma. Adipophilin stained the rim of cytoplasmic lipid droplets in various tumor types, including sebaceous carcinomas (30/30, 100%), squamous cell carcinoma with clear cell change (21/28, 75%), and eccrine-apocrine carcinomas (25/43, 58%). On the other hand, perilipin expression was seen in 13 (43%) of 30 sebaceous carcinoma and only 1 hidradenocarcinoma. The remaining 28 squamous cell carcinomas with clear cell change and 42 eccrine-apocrine carcinomas were negative. Although specific for invasive sebaceous carcinoma, perilipin expression was not helpful in distinguishing sebaceous carcinoma in situ from squamous cell carcinoma in situ with clear cell change. The expression of adipophilin seen in variety of cutaneous tumors suggests that the biosynthesis of lipid is altered in these neoplasms.
    Human pathology 05/2013; · 3.03 Impact Factor
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    ABSTRACT: Calciphylaxis is a rare and life-threatening disease characterized by cutaneous necrosis and vascular calcification. Often, skin biopsy specimens are not diagnostic because of the limited depth of the specimen, biopsy site, and clinical stage. To better understand the utility of various histologic features in rendering the diagnosis of calciphylaxis and to compare von Kossa versus Alizarin red stains in the detection of calcium deposits, we retrospectively analyzed the histologic features and histochemical stain findings of 56 skin biopsies from 27 consecutive patients seen at Massachusetts General Hospital from October 2002 to April 2012, with confirmed diagnosis of calciphylaxis and compared with that of 19 skin biopsies from 17 patients with other disease processes. All forms of vascular calcification and vascular thrombosis were significantly associated with cutaneous calciphylaxis. Perieccrine calcium deposition, highly specific to calciphylaxis, was the only form of calcium deposition noted in 4 (7%) skin biopsies from patients with calciphylaxis. Although the staining appears to be comparable, the deposits seen on Alizarin red appeared larger and were birefringent. Although subtle, perieccrine calcification may aid in the diagnosis of calciphylaxis in settings where typical vascular and extravascular calcification are not identified. Performing both von Kossa and Alizarin red stains might increase the detection of calcium deposit.
    The American Journal of dermatopathology 01/2013; · 1.30 Impact Factor
  • Meera Mahalingam, Mai P Hoang
    Human pathology 01/2013; · 3.03 Impact Factor
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    ABSTRACT: Sarcomatoid carcinoma or carcinosarcomas of the skin are rare. Basal cell carcinoma (BCC) with osteosarcomatous differentiation is the second most common sarcomatoid carcinoma of the skin, following squamous cell carcinoma with heterologous mesenchymal differentiation. There are only 11 cases of BCC with osteosarcomatous component reported in the literature, with limited documented molecular analyses. The authors report the clinical and histological features of 2 cases with molecular analyses for recurrent mutations in 17 cancer genes. In both cases, the epithelial or BCC component was positive for BerEP4 and high-molecular weight cytokeratin, whereas the sarcomatous component was negative for both markers. Mutational analyses revealed TP53 mutation in 1 case with p53 expression noted in both components. The other case was negative for both p53 expression and TP53 mutation.
    The American Journal of dermatopathology 12/2012; · 1.30 Impact Factor
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    ABSTRACT: People with pale skin, red hair, freckles and an inability to tan—the 'red hair/fair skin' phenotype—are at highest risk of developing melanoma, compared to all other pigmentation types 1 . Genetically, this phenotype is frequently the product of inactivating poly-morphisms in the melanocortin 1 receptor (MC1R) gene. MC1R encodes a cyclic AMP-stimulating G-protein-coupled receptor that controls pigment production. Minimal receptor activity, as in red hair/fair skin polymorphisms, produces the red/yellow pheome-lanin pigment, whereas increasing MC1R activity stimulates the pro-duction of black/brown eumelanin 2 . Pheomelanin has weak shielding capacity against ultraviolet radiation relative to eumelanin, and has been shown to amplify ultraviolet-A-induced reactive oxygen species 3–5 . Several observations, however, complicate the assumption that melanoma risk is completely ultraviolet-radiation-dependent. For example, unlike non-melanoma skin cancers, melanoma is not restricted to sun-exposed skin and ultraviolet radiation signature mutations are infrequently oncogenic drivers 6 . Although linkage of melanoma risk to ultraviolet radiation exposure is beyond doubt, ultraviolet-radiation-independent events are likely to have a signifi-cant role 1,7 . Here we introduce a conditional, melanocyte-targeted allele of the most common melanoma oncoprotein, BRAF V600E , into mice carrying an inactivating mutation in the Mc1r gene (these mice have a phenotype analogous to red hair/fair skin humans). We observed a high incidence of invasive melanomas without providing additional gene aberrations or ultraviolet radiation exposure. To investigate the mechanism of ultraviolet-radiation-independent carcinogenesis, we introduced an albino allele, which ablates all pigment production on the Mc1r e/e background. Selective absence of pheomelanin synthesis was protective against melanoma develop-ment. In addition, normal Mc1r e/e mouse skin was found to have significantly greater oxidative DNA and lipid damage than albino-Mc1r e/e mouse skin. These data suggest that the pheomelanin pigment pathway produces ultraviolet-radiation-independent carcinogenic contributions to melanomagenesis by a mechanism of oxidative damage. Although protection from ultraviolet radiation remains important, additional strategies may be required for optimal mela-noma prevention. To study the role of pigmentation in BRAF V600E melanoma develop-ment, we used a series of genetically matched mice on the C57BL/6 background with various pigmentation phenotypes (Fig. 1a). To mimic dark-skinned individuals with a high eumelanin-to-pheomelanin ratio, we used mice with the wild-type C57BL/6 pigmentation pheno-type ('black'). To mimic individuals with the red hair/fair skin pheno-type who carry a high pheomelanin-to-eumelanin ratio, we used mice with premature termination of the Mc1r transcript (Mc1r e/e , 'red') 8 . To mimic individuals with albinism who have no melanin, we used mice with an inactivating mutation at the tyrosinase locus (Tyr c/c , 'albino') 9 . Because tyrosinase is the initial and rate-limiting enzyme in melanin synthesis, albino melanocytes do not produce any pigment, but are normal in number and viability 10 . We generated two variants of each pigmentation phenotype. One variant contains melanocytes in the dermis. A second matched variant contains transgenic stem cell factor expressed under the keratin 14 promoter (K14-SCF), which mimics SCF expression in human epi-dermal keratinocytes and results in epidermal melanocyte localization 11 . To create a genetic context primed for the induction of melanoma we also introduced into each of our six variants a system for inducible, melanocyte-specific expression of oncogenic BRAF V600E (ref. 12). In humans, mice and zebrafish, expression of BRAF V600E in melanocytes primarily causes benign nevi, rather than melanoma 12–15 . In this con-text, malignant melanoma progression is thought to be constrained by
    Nature 10/2012; · 38.60 Impact Factor
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    ABSTRACT: The histologic distinction between microcystic adnexal carcinoma (MAC) and desmoplastic trichoepithelioma (dTE) can be challenging in the setting of a superficial biopsy. However, accurate diagnosis has treatment implication because the standard of care for MAC is wide local excision but more conservative care for dTE. We reviewed the histologic features of 30 MAC and 39 dTE cases and performed cytokeratin (CK) 17, CK19, and epidermal growth factor receptor (EGFR) immunostains on 20 MACs and 18 dTEs. MAC cases occurred in older patients in comparison with dTE (median, 67 years vs. 34 years). The head and neck was the most commonly involved site, 88% and 89% for MAC and dTE, respectively. In addition to features previously reported as specific for MAC, such as skeletal muscle and subcutaneous tissue invasion, perineural invasion, and ductal differentiation, we found the presence of mitotic figures to be significantly more frequent in MAC cases (P < 0.0001). In contrast, the presence of keratocyst, keratin granuloma, and calcification was significantly more frequent in dTE cases (P < 0.0001). CK19 seems to be a helpful adjunct because its expression was seen in 70% (14/20) of MAC versus 22% (4/18) of dTE cases (P = 0.0044); however, the clinical usefulness in individual cases may be limited because of the overlapping immunoprofile. CK17 and EGFR expression was seen in all the MAC and dTE cases. Low polysomy of EGFR gene was observed in only one MAC case, suggesting that molecular mechanisms other than gene amplification play a role in EGFR overexpression.
    The American Journal of dermatopathology 06/2012; · 1.30 Impact Factor

Publication Stats

1k Citations
539.00 Total Impact Points


  • 2009–2014
    • Harvard Medical School
      • Department of Pathology
      Boston, Massachusetts, United States
    • Massachusetts General Hospital
      • Department of Pathology
      Boston, Massachusetts, United States
    • University of Massachusetts Medical School
      • Department of Pathology
      Worcester, MA, United States
  • 2010–2013
    • Boston University
      • Department of Dermatology
      Boston, MA, United States
    • Duke University Medical Center
      • Department of Pathology
      Durham, North Carolina, United States
  • 1998–2012
    • University of Texas Southwestern Medical Center
      • • Department of Dermatology
      • • Department of Pathology
      Dallas, Texas, United States
  • 2008
    • Partners HealthCare
      Boston, Massachusetts, United States
  • 2007
    • Children's Medical Center Dallas
      Dallas, Texas, United States
  • 2000
    • University of Texas MD Anderson Cancer Center
      • Department of Pathology
      Houston, TX, United States