Extranodal nasal-type natural killer/T-cell lymphoma with penile involvement: a case report and review of the literature

BACKGROUND Extranodal natural killer/T-cell lymphoma (ENKTL) usually presents as a localized disease in the nasal cavity; extension to the male genitourinary system is very rare and has been characterized only recently. Most cases present with predominantly extranodal involvement, advanced stage disease, highly aggressive course, and strong association with Epstein-Barr virus (EBV). While metastasis is common in ENKTLs, the penis is rarely involved in both nasal and non-nasal ENKTLs and only one report was published to date. CASE PRESENTATION One patient with NK/T-cell lymphoma, presented initially with a penile mass, is reported. The 58-year-old man who presented with progressive painless penile swelling underwent penectomy for penile tumor. Histologically, the glans and foreskin revealed neoplastic infiltration of medium-sized lymphoma cells expressing CD56, CD3, granzyme-B, and labeled for EBV-encoded RNA in situ hybridization. Findings were consistent with NK/T-cell lymphoma. By detailed history, we learned that the patient had nasal obstruction for more than 10 years. Nasopharyngeal involvement was screened with PET-CT; ENKTL was diagnosed after a nasopharyngeal biopsy. The final diagnosis was primary nasal NK/T-cell lymphoma, with metastasis to the penis. Additional sites of disease appeared soon afterward (adrenal gland, liver, spleen and lymph nodes). The patient died within 4 months. CONCLUSION This study suggested that penile NK/T-cell lymphoma tends to disseminate early and pursues an aggressive course. It is imperative to distinguish nasal NK/T lymphoma from other types of tumors, because the prognosis and treatment differ significantly for secondary metastases.