So-called "malignant blue nevus": a clinicopathologic study of 23 patients.

BACKGROUND

Melanomas that arise in association with or that resemble blue nevi are extremely rare and have been termed "malignant blue nevi." The authors report on a single-institutional clinicopathologic study of "blue nevus-like melanomas" (BNLMs).

METHODS

Twenty-six patients were identified with a "malignant blue nevus" over 29 years at the Sydney Melanoma Unit. Twenty-three patients were included in the current study after pathologic review. Clinical outcomes of those patients were compared with the outcomes in a matched control group of patients with melanoma (matched for age, sex, Breslow thickness, Clark level, ulceration, and anatomic site).

RESULTS

The median patient age was 44 years, and men comprised 65% of the patients. The tumors were distributed evenly among skin sites, and their median Breslow thickness was 5.5 mm. After a median follow-up of 36.5 months, there was no difference in survival (P = .702) between patients with BNLM and patients in the control group.

CONCLUSIONS

BNLMs tended to present at a more advanced stage, with thicker primary tumors, but had a metastatic pattern comparable to and was not more aggressive in behavior than other types of melanoma. The authors concluded that BNLMs should be treated in the same way as any other melanoma variants based on clinical staging and pathologic prognostic indices.