Coexistent pulmonary cryptococcal infection and pulmonary sarcoidosis: a case report and literature review

Cryptococcus is an encapsulated, yeast-like fungus commonly responsible for infections in individuals with impaired T cell-mediated immune responses, including those with acquired immune deficiency syndrome or taking immunosuppressive agents such as steroids or cyclosporine. However, pulmonary fungal infection is rare in patients with untreated sarcoidosis. We report a case of coexistent pulmonary cryptococcal infection in a 43-year-old man with pulmonary sarcoidosis in North-western China. The patient was diagnosed with sarcoidosis via right anterior mediastinal lymph node biopsy and lung biopsy by bronchoscopy. He was treated with oral prednisone 25 mg/day and achieved complete remission of all symptoms. However, repeat chest computed tomography examination revealed enlarged nodules in the left lower lobe, but decreased bilateral diffuse small nodules in the lungs. Computed tomography-guided percutaneous lung puncture biopsy revealed cryptococcal infection. This case highlights the need to consider fungal infection in patients with sarcoidosis at initial presentation, irrespective of their use of immunosuppressive medication.