Macrophage Activation Syndrome Secondary to Underlying Sarcoidosis.

Hemophagocytic lymphohistiocytosis (HLH) due to an underlying rheumatologic condition is known as macrophage activation syndrome (MAS), a rare and serious complication that often has a delayed diagnosis. MAS can complicate any rheumatologic disease, although it is most prevalent in systemic juvenile idiopathic arthritis. MAS occurring as a sequela of sarcoidosis is seldom reported. Herein, we present an uncommon case of MAS occurring secondary to suspected extrapulmonary sarcoidosis and the associated diagnostic challenges. A 53-year-old White female presented with a 20-month history of constitutional symptoms of an unclear etiology. Her extensive workup included equivocal bone marrow and liver biopsies, suggestive of occasional hemophagocytosis. On admission, she met criteria for HLH based on the HLH-94 diagnostic guidelines. A repeat liver biopsy was performed revealing non-necrotizing granulomas in the parenchyma. Given the concern for an extrapulmonary sarcoidosis, she was started on pulse-dose steroids with subsequent symptomatic resolution. Two years later, she remains in complete remission. As a systemic disease, sarcoidosis can manifest in any organ and present in a variety of ways. While HLH and MAS have numerous etiologies, sarcoidosis should be considered as a potential underlying diagnosis, and prompt treatment initiation with steroids may reduce morbidity and mortality.