A 73-year-old woman with persistent diarrhea and onychomycosis.

We present a case of a 73-year-old woman who presented with chronic watery diarrhea, weight loss, and frequent sinus and nail fungal infections. Her previous workup with a gastroenterologist failed to reveal any causative agent for her symptoms. She considered herself healthy until a thymic tumor was discovered and removed years ago. Subsequently, she developed multiple sinus infections refractory to treatment. Relevant immunology laboratory tests were conducted, which led to the diagnosis. This case illustrated the need for a detailed history and thorough immunologic assessment, and the requirement to maintain a broad differential diagnosis.