A diagnostic predicament: activated sarcoidosis or pulmonary histoplasmosis. A case report.

We report a case of a 41-year-old man presenting with persisting fevers over 2 weeks. The patient had spent 4 weeks in Central America. He was in control of a stable stage II sarcoidosis. Laboratory and various microbiological tests as well as chest radiography led to no diagnosis. Activated sarcoidosis was hypothesized as the most likely diagnosis. However, we considered an infectious process as a differential diagnosis, in detail, the travel history imposed histoplasmosis. Chest-CT documented localized interstitial consolidations. Bronchoscopy with bronchoalveolar lavage (BAL) and biopsy was performed. Results of BAL fluid, biopsy, distinct sarcoidosis serum markers and a borderline positive histoplasmosis-serology yielded in a diagnostic dilemma as no distinct diagnosis was drawable. After the patient was already started on a prednisolone trial, the final diagnosis - pulmonary histoplasmosis - could be achieved via positive culture and PCR out of the BAL fluid. This case shows the difficult differentiation between an acute exacerbation of a chronic pulmonary disease and a concomitant infection, which was especially aggravated in this case as the histoplasmosis masqueraded an acute picture of sarcoidosis.