Malignant Acanthosis Nigricans with Recurrent Bladder Cancer: A Case Report and Review of Literature.

Acanthosis nigricans (AN) is a rare cutaneous condition that may be a manifestation of certain endocrinological or autoimmune diseases, as well as a potential marker for underlying undiagnosed cancer. AN is classified as either benign or malignant based on its clinical associations. Malignant acanthosis nigricans (MAN), which tends to be extensive and develops rapidly, is considered to be a paraneoplastic syndrome associated with advanced cancer, commonly accompanied by intra-abdominal malignancies. Bladder cancer with AN concomitant with tripe palms (TP) and/or mucosal involvement is relatively rare and, to our knowledge, only seven cases of AN with bladder cancer have been reported in the English literature. However, to date, there have been no reports of bladder cancer with AN concomitant with TP, skin and mucosal involvement. Here, we present a case of a 71-year-old male diagnosed with AN coexisting with recurrent bladder cancer and simultaneous TP and oral AN. In addition, we provide a brief review of the available literature on this topic. Early recognition of skin features associated with internal malignancies provides an opportunity for early diagnosis, treatment of the internal malignancy and monitoring of tumor recurrence.