Treatment-induced sarcoidosis in a patient with metastatic clear cell ovarian cancer.

Sarcoidosis is a granulomatous disease that commonly presents with lung or lymphatic system manifestations. Diagnosis is often delayed due to variable clinical presentation. This is a case of a patient with metastatic clear cell ovarian cancer who developed disease reoccurence after definitive treatment with surgery and adjuvant chemotherapy. She was treated with multiple lines of therapy, including investigational agents. During this time, she developed mediastinal lymphadenopathy and hypercalcaemia. Due to suspicion that her presentation was not a manifestation of her malignancy, she underwent two lymph node biopsies revealing granulomatous disease. She was initiated on prednisone for management of sarcoidosis, which led to radiologic, laboratory and symptomatic improvement. Although the precipitating factor for this patient's sarcoidosis cannot be definitively determined, nivolumab is a possible culprit. This case highlights the importance of a broad differential diagnosis when a patient undergoing antineoplastic treatment develops mediastinal lymphadenopathy or hypercalcaemia.