Pulmonary nodules in liver transplant recipients

Pulmonary nodules present a diagnostic dilemma in liver transplant recipients because of the broad differential diagnosis involved. Eleven of 155 (7.1%) liver transplant recipients at the Veterans Affairs Medical Center, Pittsburgh, developed pulmonary nodules. The underlying etiology included aspergillosis (3 cases), cryptococcosis (2), metastatic hepatocellular carcinoma (1), posttransplant lymphoproliferative disorder (1), Staphylococcus aureus (1), squamous cell carcinoma (1), adenocarcinoma of unknown primary site (1), and undifferentiated carcinoma (1). A review of the literature revealed 22 other liver transplant recipients with pulmonary nodules. There appears to be a definite relationship between time since transplantation and etiology of the nodule. Aspergillosis and bacterial infections appear early (within the first month), whereas nocardiosis, coccidiomycosis, tuberculosis, and cryptococcosis occur from 3 to 24 months posttransplantation. Metastatic hepatocellular carcinoma is a relatively common cause of pulmonary nodule and appears from 2 months to 2 years posttransplantation. Detection of skin lesions (indicating nocardiosis or cryptococcosis) and positive serologic tests may further narrow the diagnosis. However, radiographic appearances of nodules of differing etiology are relatively nonspecific, necessitating biopsy in virtually all cases.