Endoscopic endonasal approach for resection of sellar leiomyosarcoma metastasis: illustrative case.

backgroundLeiomyosarcoma (LMS) is a rare neoplasm that arises from tissues of embryonic mesodermal origin. Primary tissues of origin can include smooth muscle cells of the abdominopelvic viscera, blood vessels, or arrector pili muscles. LMS is known to metastasize to the lungs, with few reported cases of spread to the central nervous system. OBSERVATIONS: A 66-year-old male with cutaneous LMS of the left forearm with metastases to the lungs and kidney that had been treated with chemoradiation presented with worsening headaches. Magnetic resonance imaging revealed a sellar lesion. An endocrine workup was unremarkable. Imaging over 6 months revealed rapid interval growth. Positron emission tomography demonstrated moderate uptake. Given the rapid growth, the patient was offered an endoscopic endonasal approach for resection. Pathology confirmed LMS. LESSONS: To the authors' knowledge, this is the first documented case of LMS metastasis to the sella. Pituitary carcinoma or metastases to the sellar region should be in the differential among patients with sellar region tumors with a rapid growth rate, bony erosion, or findings of lesions in the upper cervical lymph nodes or soft tissue. Tumors that show significant interval growth should raise suspicion for nonadenomatous lesions, and surgical intervention should be considered even in the absence of endocrinological dysfunction or cranial neuropathies. https://thejns.org/doi/10.3171/CASE2435.