Multisystem involvement in extramedullary plasmacytoma: diagnostic challenges and clinical implications—a case report

Extramedullary plasmacytoma (EMP) represents 3–5% of plasma cell tumors and is commonly found in the head and neck region, upper respiratory tract, and gastrointestinal tract. Cardiac and primary lung parenchymal involvement are extremely rare. This case report describes an unusual instance of EMP involving multiple systems, including the heart, lungs, bones, eyes, lymph nodes, and skin, highlighting the complexity of multi-organ involvement and the rapid progression of lesions. A 65-year-old male of Chinese ethnicity presented with a three-month history of persistent cough and expectoration. His medical history included paroxysmal atrial fibrillation, hypertension, lacunar stroke, and coronary atherosclerosis. Imaging studies revealed a progressive pulmonary condition, and further scans identified multiple solid nodules in both lungs, hilar lymphadenopathy, and a new mass in the left atrium. A biopsy confirmed the diagnosis of plasmacytoma. Systemic anti-tumor therapy (D-BCD: daratumumab, bortezomib, cyclophosphamide, and dexamethasone) was initiated, resulting in marked regression of pulmonary lesions after the first cycle. This case of EMP underscores the importance of multimodal imaging and histopathological evaluation in managing complex lesions. The rapid progression and cardiac involvement highlight EMP’s aggressive nature, emphasizing the need for thorough assessment and prompt intervention. Further research into EMP’s aggressiveness and treatment response is crucial to improve therapeutic strategies and patient outcomes.