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.