Malignant cellular blue nevus: a clinicopathological study of 6 cases.
BACKGROUND
Malignant cellular blue nevus (MCBN) is a rare entity due to the malignant transformation of a preexisting cellular blue nevus (CBN).


OBJECTIVE
The clinical and pathologic features of 6 patients with MCBN are described.


RESULTS
Three tumors were located on the scalp, 2 on the trunk and 1 on the neck. The lesions, present from birth or childhood, had enlarged rapidly in the last months before excision. Histologically, there was a dermal proliferation of spindle and epithelioid atypical melanocytic cells. Some of them were heavily pigmented. Numerous atypical mitoses were seen. In 2 cases, foci of necrosis were detected. In 2 cases, remnants of CBN were also noted. MCBN has a poor prognosis and may be difficult to differentiate from so-called atypical blue nevus, metastasis of malignant melanoma and malignant transformation of combined nevus.


CONCLUSIONS
CBN may represent a precursor of malignant melanoma. In MCBN, malignant changes seem to occur in clear cells.
Aloi
F
F
Department of Dermatology, University of Turin, Italy.
Pich
A
A
Pippione
M
M
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000473:pathology*; D008875:Middle Aged; D009333:Neck; D018329:Nevus, Blue / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000601:surgery; D011230:Precancerous Conditions / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012535:Scalp; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate; D013909:Thorax