Rare Association between Sarcoidosis and Smoldering Multiple Myeloma: A Case Report

While several case reports suggest an association between sarcoidosis and multiple myeloma (MM), few cases involve smoldering MM. We report a case of sarcoidosis and smoldering MM discovered simultaneously in a patient admitted for hypercalcemia. Initial tests raised suspicion for sarcoidosis and MM, prompting invasive testing. Surgical lung biopsy revealed necrotizing granulomas, which could represent sarcoidosis in the appropriate setting. Thus, sarcoidosis was diagnosed following a negative infectious workup. Bone marrow biopsy revealed 13% plasma cells leading to subsequent diagnosis of smoldering MM. This case demonstrates the challenge of determining disease activity when other causes of CRAB symptoms are present.