A 41-year-old man with a past medical history of diabetes mellitus type II, AIDS (diagnosed 2 years earlier; CD4 count < 10), peripheral neuropathy, and pulmonary tuberculosis of 2 years duration was admitted to the hospital with abnormal liver function tests. There was a chronic hepatitis/cholestasis that had worsened while the patient was undergoing directly observed tuberculosis therapy. On admission, the patient complained of a painful swelling on his right arm. In the posterior aspect of the arm, there was a 3-4-cm subcutaneous mass that was fluctuant, mobile and tender. Incision of the mass released yellowish pus mixed with blood. Direct examination of the pus in KOH mounts and Gram-stained smears revealed subhyaline, septate, branched hyphae. When the pus was cultured on Sabouraud dextrose agar containing chloramphenicol, several velvety, olivaceous grey colonies grew after 7 days at 25 degrees C. When grown on oatmeal agar, the fungus produced subglobose, rostrate pycnidia with phialidic conidiogenous cells, and 1-celled cylindrical conidia. It was identified as Pleurophomopsis lignicola Petrak. This report describes the third known case of subcutaneous infection caused by P. lignicola in an immunocompromized patient.