Life-threatening asymptomatic incidentaloma: a case report of idiopathic CD4 lymphocytopenia and opportunistic infections.

Incidental lung nodules can be due to a variety of etiologies. Management is guided by the most likely or urgent pathology, which is frequently malignancy in an elderly smoker. We present the case of a 62-year-old, long-time smoker, with an incidental lung nodule. Pursuit of the underlying etiology revealed disseminated cryptococcal and Mycobacterium avium intracellulare infections, which are most often seen in patients with advanced human immunodeficiency virus-acquired immunodeficiency syndrome or other immunocompromise. This patient was ultimately determined to have idiopathic CD4 lymphocytopenia, a rare and poorly understood acquired immunodeficiency syndrome. Furthermore, Cryptococcus neoformans is well known to cause asymptomatic meningitis in immunocompetent individuals but is very rarely asymptomatic in the immunosuppressed, as was the case with this patient.