anal melanoma

anal melanoma

A variant of melanoma, which comprises up to 1% of anal tumours and 1% of melanomas, but 24% of mucosal melanomas.

Epidemiology
Caucasians; F > M; mean age 60; HIV increases risk.
 
Management
Radical excision; chemotherapy is of uncertain efficacy.

Prognosis
10–30% 5-year survival; > 3-mm thick, 11 months.
References in periodicals archive ?
ABSTRACT: Anal melanoma is a devastating malignancy easily confused with benign hemorrhoids.
3 While surgical and oncologic publications pertaining to anal melanoma are numerous, only one article4 is available for primary care clinicians who, in our opinion, are often unaware of the significance of this neoplasm.
Pathology of the resected specimen revealed anal melanoma with 8 mm of tumor thickness.
Biopsies revealed anal melanoma with 18 mm of tumor thickness, deeply invasive into intestinal wall and vascular structures (Fig 2).
Biopsy of the mass showed anal melanoma with tumor thickness exceeding 5 mm.
The histologic features of anal melanoma resemble those of cutaneous melanomas.
Management of anal melanoma remains a major challenge.
Anal melanomas account for about 4% of anal canal tumors and less than 1% of all melanomas.
In a study of 20 anal melanomas, Antonescu et al (66) identified 3 KIT mutation-carrying tumors, and by in vitro drug testing, showed that the KIT (L576P) mutant was responsive to specific kinase inhibitors.
60) Other studies (61,62) have shown that 62% of acral and mucosal melanomas exhibit constitutive KIT receptor activity, and that 15% of anal melanomas harbor activating KIT mutations.
L576P KIT mutation in anal melanomas correlates with KIT protein expression and is sensitive to specific kinase inhibition.
2) Anal melanomas exhibit the same immunohistochemical and ultrastructural features as their cutaneous counterparts.