Spontaneous Massive Hemorrhage Caused by Inflammatory Myofibroblastic Tumor (IMT) of the Greater Omentum: A Case Report.

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal soft tissue neoplasm. Its histologic features include proliferating fibroblastic/myofibroblastic spindle cells and a dense inflammatory infiltrate rich in plasma cells, lymphocytes, and eosinophils. However, it can exhibit aggressive behavior, including local invasion, malignant transformation, recurrence, and even metastasis. We report a case of a 27-year-old man who experienced a spontaneous massive hemorrhage caused by IMT of the greater omentum and who had previously undergone right upper lobectomy for the IMT of the lung. Furthermore, we deduced that there were metastatic tumors in the sternum, thoracic vertebrae, lumbar vertebrae, ilium, sacrum, and right femur, as well as in soft tissue masses located in the retroperitoneum and the right buttocks. It presents with diverse clinical manifestations and lacks specific imaging characteristics. Definitive diagnosis relies on histopathological examination and immunohistochemical analysis. Given that these tumors may recur locally and, in rare cases, undergo malignant transformation, targeted therapy may be warranted. Timely diagnosis and surgical resection are crucial, and long-term follow-up is essential for ongoing surveillance.