Pancytopenia Revealing Medullary Granulomatosis : An Unexpected Diagnosis of Systemic Familial Sarcoidosis

Abstract Sarcoidosis is a granulomatous disease of unknown origin, characterized by highly variable clinical presentations. Diagnosis is based on compatible clinical features, the presence of non-caseating granulomas on biopsy, and the exclusion of other causes of granulomatous diseases. Extrapulmonary involvement is rare, particularly bone marrow involvement, which is usually observed in the context of systemic sarcoidosis. Bone marrow sarcoidosis is extremely rare. Familial forms are also uncommon, accounting for less than 5% of cases. This article reports a case of medullary sarcoidosis revealed by pancytopenia. Observation : A 54-year-old hypertensive patient presented with an anemic syndrome associated with prolonged low-grade fever, weight loss, splenomegaly, diffuse papular skin lesions, and minor neurological signs. Laboratory tests revealed pancytopenia, hypercalcemia, polyclonal hypergammaglobulinemia, moderate renal impairment, and elevated angiotensin-converting enzyme levels. Infectious and autoimmune serologies were negative. Bone marrow biopsy revealed non-caseating granulomas, which were also confirmed in skin and salivary gland biopsies. A diagnosis of bone marrow sarcoidosis was established. The patient was treated with corticosteroids, resulting in good clinical and biological improvement, despite persistent thrombocytopenia and the onset of corticosteroid-induced diabetes. A family history of sarcoidosis was later reported. Discussion : Sarcoidosis is a rare systemic inflammatory condition primarily affecting the lungs. Medullary involvement, though rare, can present as pancytopenia. Bone marrow biopsy is key to diagnosis, and biological abnormalities such as anemia, leukopenia, and elevated sedimentation rate are common. Treatment is based on corticosteroids, but other immunosuppressants may be needed if the response is inadequate. Lymphopenia is often associated with poor prognosis. The rarity of the cases and the diversity of symptoms make medullary sarcoidosis difficult to diagnose. Conclusion : Bone marrow sarcoidosis is a rare and challenging condition to diagnose. It should be considered in cases of unexplained pancytopenia, particularly when systemic symptoms are present. Bone marrow biopsy is a key diagnostic tool. Corticosteroid therapy remains the first-line treatment and requires close monitoring. This case highlights the importance of a multidisciplinary approach in managing atypical forms of sarcoidosis.