Pulmonary and Urologic Sarcoidosis as a Cause of Intermittent Fever of Unknown Origin.

Diagnosing fever of unknown origin (FUO) presents a substantial challenge due to its potential association with various diseases affecting different organs. In 1961, Petersdorf and Beeson initially defined FUO as a condition characterized by a temperature exceeding 38.3 °C on at least three occasions over a minimum three-week period. Despite a week of inpatient investigation, a definitive diagnosis remains unclear.  Sarcoidosis, a granulomatous disease impacting multiple systems, is among the causes of FUO. While the lungs are commonly affected, any organ can be involved, leading to diverse manifestations and clinical courses. Diagnosis relies on clinicopathologic findings and the exclusion of alternative causes of granulomatous disease. The hallmark of sarcoidosis is the development of granulomas in affected organs. Here, we present the case of a 61-year-old man with a history of recurrent spontaneous periurethral abscesses who underwent multiple urological interventions. He developed FUO during hospitalization following treatment for the infectious condition.