False-positive cryptococcal antigen in a patient with cavitary pulmonary nodules and haemoptysis.

A woman in her early 50s presented with haemoptysis and cavitary pulmonary nodules. Initial testing showed a low-titre positive cryptococcal antigen (CrAg); however, repeat testing on two occasions was negative. Her cavitary nodules were ultimately attributed to an overlap systemic autoimmune rheumatic disease. She achieved complete clinical and radiological resolution with corticosteroid therapy. This case highlights the importance of recognising false-positive serum CrAg results.