Extramedullary Waldenström Macroglobulinemia Presenting as a Subcutaneous Penile Mass.

Primary penile malignancy is a rare occurrence in the United States, with squamous carcinoma being the most common aetiology. Non-squamous penile cancers are scarcely reported in the literature. We present a unique case of a 65-year-old male with a history of Waldenström macroglobulinemia (WM) previously in remission complaining of a painless subcutaneous bump on the base of the penis. Biopsy with histological and immunohistochemical analysis confirmed the recurrence of WM. This novel case illustrates an unusual presentation of the disease after being successfully managed with chemotherapy and immunotherapy in an asymptomatic individual. There is only another reported case in the literature of a patient with a similar presentation. We highlight the clinical features and presentation of this condition, including a consensus for the approach and management of non-Hodgkin's lymphomas of the penis.