Multiple myeloma is characterized by the abnormal production of immunoglobulins by malignant plasma cells in the bone marrow. Extramedullary plasmacytomas, tumours formed by these cells outside the bone marrow, typically occur in the upper respiratory tract and occasionally in the urogenital tract. Primary plasmacytoma of the urethra is extremely rare, with only seven reported cases.

A 50-year-old male with a history of laparoscopic cholecystectomy and multiple prior urethral catheterizations presented with urinary straining. Initially diagnosed with urethral stricture disease based on symptoms and imaging, he underwent a micturating cystourethrogram revealing distal bulbar and proximal penile strictures.(figure 1) Physical Examination was normal.

During Johanson stage 1 urethroplasty, thickened and firm peribulbar urethral tissue was found, prompting a frozen section analysis that identified plasma cells(figure 2) positive for CD138 and kappa restriction, with negative lambda and IgG4 positivity- indicating plasmacytoma. Bone marrow biopsy indicated 5-10% plasma cell involvement with CD138 highlights. Serum electrophoresis confirmed kappa cells, while PET CT and MRI ruled out systemic involvement. A rare diagnosis of extramedullary plasmacytoma was made, leading to planned radiotherapy with ongoing follow-up.

Surgery and radiotherapy are primary treatments; chemotherapy is for disseminated cases. Detailed histopathological examination is crucial for diagnosing rare conditions like extramedullary plasmacytoma in urethral strictures. Extramedullary plasmacytoma, though rare, can be managed if incidentally found during the management of urethral disease.