A Rare Case of Extra-Pulmonary Sarcoidosis With Only Initial Presentation of Hypercalcemia

Sarcoidosis is a systemic disorder characterized by the aberrant development of granulomatous inflammation within various organs in the body. In over 90% of cases, sarcoidosis typically manifests initially in the intra-thoracic region, characterized by pulmonary involvement or mediastinal lymphadenopathy. It is rare for sarcoidosis to manifest exclusively as extra-thoracic involvement and even more rarely for hypercalcemia to be the only initial sign. We present a case of a 70-year-old female with hypercalcemia and elevated 1,25-dihydroxyvitamin D3 (1,25(OH)2 D) which raised the suspicion of a granulomatous disease. Granulomatous diseases increase levels of 1,25(OH)2 D via the abnormal expression of 1 alpha-hydroxylase enzyme; therefore, these conditions should be considered in the differential diagnosis when encountered with hypercalcemia. PET-CT showed increased FDG uptake in the reticuloendothelial system. An easily accessible inguinal lymph node biopsy was performed which revealed non-necrotizing granulomatous inflammation. Other causes of non-necrotizing granulomatous diseases, cancer, and lymphoma were ruled out, leading to sarcoidosis being considered as a possible diagnosis. When diagnosing sarcoidosis, other potential causes of granulomatous inflammation need to be ruled out definitively via laboratory findings, imaging, and tissue histopathology before initiation of treatment with steroids. Treatment with glucocorticoids remains the mainstay therapy of 1,25(OH)2 D-mediated hypercalcemia associated with sarcoidosis. The patient was accordingly treated with prednisone which led to the normalization of calcium and 1,25(OH)2 D levels within three weeks. Here, we discuss the clinical features and investigations of extra-pulmonary sarcoidosis for early diagnosis and management.