Cutaneous Pneumocystis jirovecii infection in an allogeneic stem cell transplant recipient

Pneumocystis jirovecii is an opportunistic fungus that infects the lungs but can involve other organs, including the skin and lymph nodes. Risk factors include human immunodeficiency virus (HIV), solid organ/haematological malignancies and a CD4 cell count of fewer than 200 cells/µl. Pneumocystis jirovecii pneumonia (PJP) infection is reported less frequently these days with the advent of prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX). We report a case of extrapulmonary PJP infection in a patient while receiving pentamidine prophylaxis in a T-cell prolymphocytic leukaemia, who underwent an allogeneic stem cell transplant. There are plenty of reported cases of PJP on pentamidine prophylaxis; however, none had cutaneous PJP infection. Cutaneous P. jirovecii infection (CPJ) is an extrapulmonary infection that is rarely reported. Our patient’s skin biopsy was inconclusive, but the skin nodules improved once he was initiated on TMP-SMX. Many transplant patients cannot tolerate TMP-SMX for various reasons and are placed on second-line prophylaxis for PJP, which does not prevent extrapulmonary PJP infections. Our case highlights the challenges of diagnosing such a rare infection in immunocompromised patients. Extrapulmonary PJP should be suspected in patients with a history of pulmonary PJP and persistent elevated Fungitell® levels in low CD4 counts.