AMP case report: Identifying the signal in the signal: incidental detection of B-cell lymphoproliferative disorder-related variants in the molecular profiling of a spindle cell sarcoma
July 2025—We report the case of a 75-year-old female who initially presented with a 10-cm left pretibial mass on MRI. A biopsy revealed a high-grade spindle cell sarcoma with myofibroblastic differentiation. PET CT showed intense uptake in osseous lesions at the scapula, vertebral bodies, iliac bones, sacrum, and femoral head. A sacrum biopsy confirmed metastatic spindle cell sarcoma. The patient underwent chemotherapy and radiotherapy. A follow-up CT scan several months later revealed new liver and lung metastases, prompting molecular analysis of the sacrum specimen.