Isolated Hilar Mass in Unicentric Castleman Disease: Surgery As the Definitive Diagnosis and Treatment.

Castleman disease is a rare group of benign B-cell lymphoproliferative disorders characterised by enlarged lymph nodes, presenting either as unicentric, involving a single enlarged lymph node, or multicentric, involving multiple lymph nodes. Symptoms range from mild to life-threatening. Although it is considered a benign condition, it needs to be differentiated from similar presenting malignancies such as carcinoid tumour and lymphoma. This differentiation often presents a clinical challenge. We present a case of a 47-year-old male who presented with lower back pain and mild shortness of breath after a fall. On routine imaging, a 6.4-cm mass was incidentally found. Biopsies and both fluorodeoxyglucose positron emission tomography (FDG PET) and gallium-68 DOTA-[Tyr³]-octreotate (DOTATATE) positron emission tomography proved inconclusive in diagnosing the mass. In this case, diagnostic certainty was only gained after an en bloc bilobectomy. We discuss the challenges and options of gaining a definitive diagnosis, while considering the risks and benefits of invasive methods such as surgery in what is considered a benign disease. However, in this case, surgery resulted in complete resolution of symptoms and positive results at follow-up.