Primary leiomyosarcoma of bones – a rare entity in two different presentations

Introduction. Leiomyosarcomas (LMS) originate from smooth muscle cells. They are very rare malignant neoplasms. Bony Leiomyosarcoma is a variant of spindle cell sarcoma, primarily affecting long bones, predominantly the distal femur and the proximal tibia followed by craniofacial skeleton. Aim. To describe clinical presentation and diagnostic approach of primary leiomyosarcoma of bones in two different patients. Description of the cases. Case 1. A 64-year-old male with a fracture of left distal femur after a fall was investigated and found to have a pathological fracture. An open biopsy of the fracture site confirms leiomyosarcoma. Case 2. A 58-year-old previously healthy female presented with a swelling on right side mandibular region. Orthopantomogram radiograph (OPG) of mandible and Cone beam CT (CBCT) mandible was taken initially and revealed a large area of bone destruction of the right side of the mandible associated with a soft tissue mass. Initial incisional biopsy made the diagnosis of spindle cell sarcoma followed by excisional biopsy, which confirms the diagnosis of moderately differentiated leiomyosarcoma. Conclusion. Primary leiomyosarcoma of bones is very rare. Imaging features are helpful in the evaluation of such conditions, but final diagnosis should be based on histopathologic and immunohistochemical features.