Genital Lymphoma Presenting as Pyrexia of Unknown Origin

Fever/pyrexia of unknown origin is defined as temperature > 38.5 degrees C lasting for > 3 weeks, of which at least 2 weeks have been spent in thorough investigations. We present a case of an elderly gentleman who had pyrexia of unknown origin and whose PET scan was useful to localize the site of extranodal lymphoma. An 80-year-old gentleman presented with intermittent fever for past 2 months. He reported loss of appetite and subsequent weight loss. There was no demonstrable abnormality on clinical examination. His blood cytology, blood biochemistry, and conventional radiology were unremarkable. He was referred for a whole-body F-18 FDG PET/CT scan. The study revealed intense metabolic activity within the penis. Clinically, there were no signs of inflammation in the genitals. On a follow-up visit, tenderness was observed during per rectal examination. Another follow-up sonography revealed inflammation in the epididymis. Hence, he underwent biopsy of the testicle and scrotal tissue, which revealed non-Hodgkin lymphoma.