Melanocytic matricoma with atypical features: A case of malignant melanocytic matricoma?

Melanocytic matricoma is a rarely reported, benign cutaneous adnexal neoplasm composed of epithelial cells exhibiting differentiation towards hair matrix as well as admixed, pigmented, dendritic melanocytes. The proposed malignant counterpart to melanocytic matricoma, malignant melanocytic matricoma (MMM), is even more rare. Here we report a case of a melanocytic matricoma with atypical features in a 92-year-old female with a 1.2-cm pigmented nodule on the right nasal sidewall. Histopathology revealed a well-circumscribed dermal tumor composed of atypical matrical cells with scattered aggregates of anucleate keratinocytes (ghost cells), prominent intratumoral pigment, numerous mitotic figures (88 mitosis/10 high-power field [HPF]), and intermixed dendritic melanocytes. A literature review was performed for MMM to determine if the current case fit diagnostic criteria for this entity. Including the current case, 12 cases of MMM were identified and analyzed to investigate common clinical and histopathologic features. MMM commonly occurred on the head and neck (7/12 cases) of older individuals (median age of 80) with a slight male predominance (male-to-female ratio of 3:1) and on histopathology presented as a multinodular dermal tumor composed of mitotically active (average mitotic rate of >50 mitoses/10 HPF) pleomorphic epithelial cells with foci of ghost cells. Dendritic melanocytes were found throughout the tumor lobules in all cases. Given that only two of 12 cases have exhibited locally aggressive behavior, further study is warranted to determine the true malignant potential of MMM.

Expression of MART-1 in human uveal melanoma cell lines / 中华眼底病杂志

Objective To observe the expression and transcription of MART-1 in human uveal melanoma cell lines 92-1,92-2,Ocm3,Me1285,as well as the possible effect ofmethylation on its expression.Methods The cell lines 92-1,92-2,Ocm3 and Me1285 were cultured routinely and tested for MART-1 expression at protein and mRNA level by FACS analysis,Western blot and RT-PCR respectively.Methylation status of the MART-1 promoter region in all the cell lines were checked by Southern blots of DNA digested with methylation sensitive restriction enzymes.Results As observed in FACS analysis and Western blot,92-1,92-2 and Ocm3 were MART-1 positive cell lines while Me1285 was negative cell line.Consistent with protein analysis,92-1 and Ocm3 cell lines showed MART-1 specific PCR products and there was no product in Me1285 cell line in RT-PCR.The MART-1 positive cell lines,92-1,92-2,and Ocm3 show methylation at the MspⅠ/Hpa Ⅱ site,and the Nru Ⅰ sites of all positive cell lines are not methylated.The MART-1 negative cell line Me1285 shows hyperrnethylation at the Nru Ⅰ site and the Msp Ⅰ/Hpa Ⅱ site is not methylated.Conclusions MART-1 could be expressed in human uveal melanoma cell lines 92-1,92-2 and Ocm3.The change of methylation status of MART-1 promoter may correlate with the transcription of MART-1.

Perivascular Epithelioid Cell Tumor in the Stomach.

Perivascular epithelioid cell tumors or PEComas can arise in any location in the body. However, a limited number of cases of gastric PEComa have been reported. We present two cases of gastric PEComas. The first case involved a 62-year-old woman who presented with a 4.2 cm gastric subepithelial mass in the prepyloric antrum, and the second case involved a 67-year-old man with a 5.0 cm mass slightly below the gastroesophageal junction. Microscopic examination revealed that both tumors were composed of perivascular epithelioid cells that were immunoreactive for melanocytic and smooth muscle markers. Prior to surgery, the clinical impression of both tumors was gastrointestinal stromal tumor (GIST), and the second case was erroneously diagnosed as GIST even after microscopic examination. Although gastric PEComa is a very rare neoplasm, it should be considered in the differential diagnosis of gastric submucosal lesions.

Perivascular Epithelioid Cell Tumor in the Stomach

Perivascular epithelioid cell tumors or PEComas can arise in any location in the body. However, a limited number of cases of gastric PEComa have been reported. We present two cases of gastric PEComas. The first case involved a 62-year-old woman who presented with a 4.2 cm gastric subepithelial mass in the prepyloric antrum, and the second case involved a 67-year-old man with a 5.0 cm mass slightly below the gastroesophageal junction. Microscopic examination revealed that both tumors were composed of perivascular epithelioid cells that were immunoreactive for melanocytic and smooth muscle markers. Prior to surgery, the clinical impression of both tumors was gastrointestinal stromal tumor (GIST), and the second case was erroneously diagnosed as GIST even after microscopic examination. Although gastric PEComa is a very rare neoplasm, it should be considered in the differential diagnosis of gastric submucosal lesions.

Report of two cases of vacuolar interface dermatitis initially suspected as melanoma in situ and review of the literature / Relato de dois casos de dermatite de interface vacuolar, inicialmente diagnosticados como melanoma in situ, e revisão da literatura

ABSTRACT The diagnosis of melanocytic lesions can be challenging and immunohistochemical study is a valuable tool for dermatopathologists. We report two cases initially simulating melanoma in situ, reviewing the histopathological and immunohistochemical findings and the cases published in the literature with similar findings/results. We emphasize the importance of clinicopathological correlation in the evaluation of lesions with interface changes and in the "pseudomelanocytic nests", which may simulate melanoma in situ. We also highlight the importance of using a immunohistochemistry panel in addition to Melan-A, in the study of these lesions.

RESUMO O diagnóstico de lesões melanocíticas pode ser desafiador, e o estudo imuno-histoquímico é uma ferramenta valiosa para os dermatopatologistas. Relatamos dois casos inicialmente diagnosticados como melanoma in situ, avaliando os achados histopatológicos e imuno-histoquímicos e os casos publicados na literatura com resultados semelhantes. Ressaltamos a importância da correlação clinicopatológica na avaliação das lesões com danos na interface e nos "ninhos pseudomelanocíticos", que podem simular melanoma in situ. Destacamos também a importância da utilização de um painel de imuno-histoquímica, além do Melan-A, no estudo dessas lesões.