Correlated improvement of mucosal malignant acanthosis nigricans and metastatic urothelial carcinoma with oncologic therapy

Malignant acanthosis nigricans (AN) is a rare paraneoplastic phenomenon, most often associated with underlying gastrointestinal malignancy.1,2 There are several reports of this entity and its diagnostic challenges in the literature,3-10 but the course of cutaneous manifestations is not well-defined, making it difficult to counsel patients regarding potential clinical outcomes. In this article, we report a case of malignant AN, presenting as mucosal papillomatosis, with near-complete resolution correlated with treatment of the underlying malignancy.