Congenital melanoma: a case suggesting rhabdomyogenic differentiation.
A newborn girl had some subcutaneous masses within a giant congenital melanocytic nevus in the left parietal area. Microscopic examination revealed melanoma. The tumor consisted of two different patterns, being composed partly of epithelioid cells and partly of spindle-shaped cells. Immunohistochemically the epithelioid cells showed a positive reaction for HMB-45 and NKI/C3, and a negative reaction for desmin and alpha-sarcomeric actin. The spindle-shaped cells showed a negative reaction for HMB-45 and NKI/C3, and a positive reaction for desmin and alpha-sarcomeric actin. Ultrastructurally the spindle-shaped cells had some schwannian features, namely, a basal lamina, interdigitating cell processes, and junctional complexes. The pathologic findings of our case suggest possible direct rhabdomyogenic differentiation of melanoma cells.
Department of Pediatrics, National Okayama Hospital, Japan.
T
T
Koyama
M
M
Murakami
O
O
Nishihara
T
T
Masuda
D000951:Antigens, Neoplasm; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D008545:Melanoma / Q000151:congenital* / Q000276:immunology / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000032:analysis; D012536:Scalp Dermatoses / Q000151:congenital* / Q000473:pathology*; D012878:Skin Neoplasms / Q000151:congenital* / Q000473:pathology*
D000951:Antigens, Neoplasm; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins