Rapidly Enlarging Giant Intramuscular Myxoma of the Distal Gluteus Maximus during Late Pregnancy
Year: 2026
Type: article
Abstract: Introduction: Intramuscular myxoma is a rare benign mesenchymal tumor of skeletal muscle that usually presents as a slowly enlarging, painless mass. Case Report: We report a giant intramuscular myxoma of the distal gluteus maximus in a 34-year-old woman. The lesion became clinically apparent during the third trimester of her first pregnancy and enlarged rapidly over approximately 6 months. Three months after cesarean delivery, she presented with severe sitting intolerance, difficulty breastfeeding while seated, and burning pain radiating along the sciatic nerve distribution. Magnetic resonance imaging demonstrated an approximately 154 × 155 × 156 mm well-circumscribed intramuscular mass adjacent to the ischium and compressing the sciatic nerve, without osseous destruction; however, its rapid growth and imaging features raised concern for a malignant myxoid soft-tissue neoplasm. A preoperative core needle biopsy showed fibrous and myxoid tissue, with no atypia or malignant cells identified in the sampled material. Complete en bloc excision was performed. Histopathologic and immunohistochemical evaluation confirmed intramuscular myxoma, and the closest surgical margin was 1 cm. The postoperative course was uneventful; symptoms resolved, she was able to continue breastfeeding, and no clinically evident local recurrence was observed during 24 months of clinical follow-up. Conclusion: This case highlights that a histologically benign intramuscular myxoma may exhibit rapid growth during late pregnancy, reach giant size, and mimic a malignant process, thereby creating substantial preoperative diagnostic uncertainty.
Authors: Cem Güneri, Yasin Köker, İsmet Teoman Benli
Institution: Ufuk University
Language: English
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $250
OpenAlex ID: W7225570835