Linfoma No-Hodgkin primario de sacro. Presentación de un caso clínico y revisión de la literatura.

Introduction Bone lymphoma is a very rare entity. It constitutes less than 2% of lymphomas and the sacrum is an unusual primary location. Only 11 cases have been described to date. Objective To describe a case of primary sacral lymphoma in a 46-year-old patient after reporting lumbar pain with radiculopathy of one month's evolution. Material and methods A 46-year-old female patient with lumbar pain of one month's evolution of mechanical characteristics with radiculopathy S1 of the right leg. No acute bone injury was observed in the X-rays performed. A CT scan was performed in a private center that reported a lytic lesion of 28 x 97 mm diameter in the right sacral wing with malignant characteristics. MRI is requested, which confirms the lesion with extension to soft tissues. Tumor markers and plasma proteins were not elevated. Biopsy with histopathological analysis reported a diffuse large B-cell lymphoma with positivity for cMYC, BCL2, BLC6, CD20, CD79a, PAX5, MUM1, with a Ki67 index of 75%. Results After diagnosis of primary diffuse large B-cell lymphoma without distant metastasis, chemotherapy treatment was started with 6 cycles of R-CHOP followed by radiotherapy. Conclusion Primary bone lymphoma is a very rare entity, and even more rare at the bone level, but knowledge of this entity is necessary to include it as a differential diagnosis of low back pain with radiculopathy.