Pathological fracture of primary lymphoma of bone: A case report on diagnosis and novel surgical management.

Primary lymphoma of bone (PLB) is an uncommon malignancy, representing ~4-5% of primary malignant bone tumors and 1% of all malignant lymphomas. Diffuse large B-cell lymphoma (DLBCL) is the most common subtype, accounting for ~80% of cases, and is highly curable with appropriate treatment. Therefore, accurate and timely diagnosis is crucial for favorable outcomes. The current study presents a 42-year-old male with primary DLBCL of the proximal humerus. The initial diagnosis was challenging due to overlapping morphological features with other small round cell tumors like Ewing's sarcoma and small cell osteosarcoma, particularly on small, decalcified biopsy samples. However, a definitive diagnosis was achieved through specific immunohistochemical markers. Following standard chemo-radiotherapy, the patient suffered a persistent, non-healing pathological fracture, resulting in severe functional shoulder impairment. This report details successful surgical management using a novel technique: A reverse shoulder megaprosthesis combined with a liquid nitrogen-treated autologous bone graft. This case report underscores PLB's diagnostic challenges and highlights a significant treatment-related complication. It presents a novel and effective surgical solution for managing pathological fractures in this context, emphasizing the necessity of a multidisciplinary, individualized approach to cure the disease, restore function and preserve the limb.