Unusual occurrence of a melanoma with intermixed epithelial component: a true melanocarcinoma?: case report and review of epithelial differentiation in melanoma by light microscopy and immunohistochemistry.
We report a case of a 27-year-old woman with a nonpigmented lesion on the right scalp. Histological examination showed a malignant nodular neoplasm with 2 distinct but intimately admixed components: a malignant melanoma with a spindle component and an unusual glandular component. Immunohistochemical studies demonstrated epithelial differentiation on the basis of cytokeratin (CAM5.2 and AE1/AE3) expression in the glandular component and melanocytic differentiation (HMB-45, PNL2, MITF, and S-100) of the spindle cell component. A single melanocytic marker (MITF) was expressed in both components, raising the possibility of dual differentiation in a single tumor, rather than the alternative considerations of a collision tumor or a reactive pseudoepitheliomatous hyperplasia with eccrine duct lumen formation within a melanoma. This unusual tumor with both melanocytic and epithelial components may represent a true melanocarcinoma, which becomes a plausible consideration, in view of melanoma plasticity and recent experimental evidence and speculation about the role of stem cells in melanoma.
Wen
Y Hannah
YH
Department of Pathology, New York University School of Medicine, New York, New York 10016, USA.
Giashuddin
Shah
S
Shapiro
Richard L
RL
Velazquez
Elsa
E
Melamed
Jonathan
J
D000230:Adenocarcinoma / Q000473:pathology; D000328:Adult; D002454:Cell Differentiation; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008544:Melanocytes / Q000473:pathology; D018328:Melanoma, Amelanotic / Q000473:pathology*; D051739:Microphthalmia-Associated Transcription Factor / Q000032:analysis; D009375:Neoplasms, Glandular and Epithelial / Q000473:pathology*; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D012535:Scalp / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*
C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor; D007633:Keratins