Anorectal melanoma. Problems of histopathologic diagnosis.

The present study discusses, in the light of the comparatively restricted data in the speciality literature, two cases of anorectal melanoma emphasizing the histologic diagnostic difficulties linked to appraisal of the limits of the benign naevus formations, predominance of the achromatous zones, alternation of the benign and sarcomatous fascicular proliferations and those of the anaplastic carcinoma type. Stress is laid on the importance for the diagnosis of the histologic examination and of serial sections, in all pedunculate formations in the anorectal region as well as of the tests applied for detecting melanin.