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.
Department of Pathology, New York University School of Medicine, New York, New York 10016, USA.
Y Hannah
YH
Wen
Shah
S
Giashuddin
Richard L
RL
Shapiro
Elsa
E
Velazquez
Jonathan
J
Melamed
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