Primary extramedullary plasmacytoma of the penis: a case report.

Extramedullary plasmacytoma involving the penis is extremely rare. Here, we describe a case of primary extramedullary plasmacytoma of the penis in a 64-year-old man who presented with a palpable penile mass. Nuclear magnetic resonance imaging revealed the presence of a large, round non-encapsulated mass in the perineum. A contrast-enhanced computed tomography scan of the pelvis showed that the mass was located in the tunica albuginea and corpora cavernosa at the base of the penis. The mass encased the urethra and demonstrated no marked enhancement during the arterial phase. The patient underwent successful surgical resection of the tumor. Histologically, the tumor was composed primarily of neoplastic plasma cells that were positive for CD38, vimentin and Ki 67. Postoperatively, the patient recovered well and exhibited no evidence of development of multiple myeloma, local recurrence or distant metastasis at 2 months post-surgery. To the best of our knowledge, our case represents the first documented case of human primary extramedullary plasmacytoma of the penis.