PET-MRI hybrid imaging in a rare case of B cell lymphoblastic lymphoma with musculoskeletal manifestation

摘要

A 44-year-old male presented with lower back pain radiating to both legs underwent magnetic resonance imaging (MRI) and was found to have a pathologic fracture of the L4 vertebra and an osteolytic lesion of the left sacrum with adjacent soft tissue infiltration. Apart from radiating back pain, the physical examination was unremarkable, the patient denied B-symptoms, and laboratory values including blood counts were within normal limits. CT-guided biopsy of the sacral lesion showed infiltrations of small blue round cells (Fig. la) with positive immunohistochemistry staining for CD99 (Fig. 1b), CD34, CD10, CD79a, CD56, nuclear PAX5 (Fig. lc), and TdT (Fig. 1d); based on which, after initial suspicion of metastatic disease or Ewing sarcoma, B cell acute lymphoblastic leukemia was diagnosed. Karyotype was normal and molecular biology analysis did not detect any common ALL-associated aberration. Importantly, upon routine bone marrow (BM) biopsy of the iliac crest, there was no evidence of malignancy, confirming localized disease.