Bone marrow sarcoidosis in Takayasu arteritis: Case report and literature review

Rationale: Takayasu arteritis (TA) is a systemic granulomatous large-vessel vasculitis predominantly involving the aorta and its primary branches. Sarcoidosis is a systemic granulomatous disorder characterized histologically by non-necrotizing epithelioid granulomas, most commonly affecting the lungs. Although the coexistence of TA and sarcoidosis has been documented, bone marrow involvement by sarcoidosis in a patient with concomitant TA has not, to our knowledge, been previously reported. Patient concerns: A 46-year-old woman with a confirmed diagnosis of TA presented with elevated systemic inflammatory markers and diffuse hypermetabolic activity on positron emission tomography (PET). Clinical, radiological, and pathological evaluations were performed. Diagnoses: Bone marrow biopsy revealed multiple non-necrotizing granulomas, supporting bone marrow involvement by sarcoidosis. This overlap of granulomatous conditions was identified in the context of persistent systemic inflammation. Interventions: Mycofenolate Mofetil was replaced by Infliximab therapy. Outcomes: The patient exhibited significant clinical improvement and marked improvement in inflammatory markers with infliximab therapy. Lessons: This case highlights the importance of maintaining a broad differential diagnosis in patients with autoimmune or inflammatory diseases who develop new systemic manifestations. Recognizing rare organ involvement in overlapping granulomatous conditions is critical for accurate diagnosis and management.