Unicentric Pulmonary Castleman Disease Mimicking Lung Cancer: A Case Report.

Castleman disease (CD) is a rare lymphoproliferative disorder typically involving mediastinal lymph nodes. Pulmonary involvement without mediastinal lymphadenopathy is extremely rare and often mimics lung cancer. A 76-year-old man presented with an incidental left upper lobe opacity that progressed over 3 years to a 29 mm heterogeneous enhancing nodule. Surgical resection revealed hyaline vascular unicentric CD with characteristic pathology. The patient remained disease-free at 24 months. Pulmonary CD should be considered in enlarging lung nodules with enhancement and no mediastinal lymphadenopathy.