[Malignant lymphoma of the prostate: a case report]

A case of a primary malignant lymphoma of the prostate is presented. An 82-year-old man visited our hospital complaining of anal pain. Digital rectal examination revealed an enlarged prostate gland, which caused a rectal stricture. A computed tomographic scan and magnetic resonance imaging (MRI) showed a large mass arising from the prostate and protruding to the rectum. According to the Working Formulation, he was diagnosed with non-Hodgkin's lymphoma of B-cell origin, diffuse, mixed, small and large cell. The results of bone marrow puncture and imaging studies led to the diagnosis of primary malignant lymphoma of the prostate. Because of poor performance status deriving from severe anal pain, radiation therapy was performed to control the pain. After improvement of his performance status, he received combination chemotherapy consisting of cyclophosphamide, adriamycin, vincristine and predonisone (CHOP regimen). His prostate markedly diminished in size, but pneumonia developed. His respiratory condition rapidly deteriorated, and he died of respiratory failure about two and a half months after the onset of his illness. Malignant lymphoma involving the prostate, whether primary or secondary, is very rare. In our understanding, this case is thought to be the 28th clinical case of a malignant lymphoma of the prostate in Japan.