Aggressive Primary Sacral Non-Hodgkin Lymphoma Associated With Systemic Lupus Erythematosus.

In this case report, we discuss a 36-year-old female patient diagnosed with a rare and aggressive sacral non-Hodgkin lymphoma. The patient presented with a rapidly progressive low back pain radiating to both lower limbs and, following a neurosurgical resection, was diagnosed with sacral non-Hodgkin lymphoma. Sacral involvement is rare among bone pathologies, accounting for only 1-7% of all spinal tumors. The association of this neoplasm with systemic lupus erythematosus at this anatomical site is uncommon and was correlated with an aggressive clinical course in our patient. Magnetic resonance imaging revealed lytic and infiltrative lesions involving the sacrum and L4 on T1- and T2-weighted sequences. Histopathological and immunohistochemical analyses confirmed a diagnosis of diffuse large B-cell lymphoma, expressing CD20, Bcl-6, Bcl-2, CD10, PAX-5, MUM-1, and c-MYC, with a high proliferative index (Ki-67: 90%), and negative for CD3, CK AE1/AE3, CD30, and TdT. During disease progression, the patient developed multiple metastases involving the brain, breast, lung, and submandibular lymph node. Despite treatment with combined chemotherapy and radiotherapy, the aggressive nature of the disease resulted in a poor prognosis.