Multicentric Castleman's disease of the lungs mimicking a multifocal adenocarcinoma

A female patient presented with fever of unknown origin, night sweats and weight loss. She had no pulmonary symptoms. Investigations revealed bilateral ground glass lung lesions which were subsequently followed-up with imaging. Two years later, a follow-up CT scan revealed an increase in the size of the lesions which exhibited a more solid appearance. A diagnostic biopsy was difficult to perform, and the patient underwent a left upper lobectomy for suspected primary lung malignancy. Histological examination showed lung involvement by Castleman's disease of plasma cell type which displayed a multifocal distribution. There was no evidence of nodal involvement. Following discussion at the multidisciplinary team meeting and correlation with radiology, a diagnosis of multicentric Castleman's disease of the lung was made. Here, we present an unusual case of multicentric Castleman's disease of the lung mimicking primary lung carcinoma. Our case highlights the importance of considering this entity in the differential diagnosis of multifocal lung lesions with a ground glass-like appearance to allow early diagnosis and management.