Primary Paraspinal Leiomyosarcoma in a 49-year-old Woman: Index Case from Pakistan

Leiomyosarcoma is a rare and aggressive malignant neoplasm arising from smooth muscle cells, commonly affecting the uterus, gastrointestinal tract, or retroperitoneum, with paraspinal involvement being extremely uncommon. Clinical symptoms include back pain, weakness, and sensory deficits due to spinal cord compression. We present a 49-year-old woman with bilateral lower extremity weakness for 15 days, lower back pain, and a left paraspinal swelling for two months. Examination showed a tender lumbar paraspinal mass, paralysis below T10, and saddle anesthesia. MRI with contrast showed large left paraspinal soft tissue mass, confirmed as grade 2 leiomyosarcoma on biopsy. Complete tumor excision was done, and postoperative recovery was uneventful. This report highlights an unusual presentation of primary lumbar paraspinal leiomyosarcoma without regional or distant metastasis in a middle-aged woman, emphasizing the importance of thorough evaluation to exclude potential primary sites. Diagnosis relies on biopsy with immunohistochemistry, while surgical excision remains the mainstay of treatment.