Low-grade endometrial stromal sarcoma in the abdominal wall: a metastatic or protopathic one?

Being a family of scarce endometrial stromal tumor, low-grade endometrial stromal sarcoma (LGESS) is an uncommon malign neoplasm, whose occurrence outside the uterus, like peritoneum, is extremely rare in the absence of metastasis or invasion of a primary uterine neoplasm. Herein we present the patient of a 44-year-old woman with no specific discomfort and abdomen-related symptoms who underwent her laparotomy after a diagnosis of recurrent LGESS. She had a history of hysterectomy for leiomyoma of uterus long before the surgical excision of her first LGESS. Exploration of the abdominal cavity revealed a colossal peritoneal mass with accompanying invasion of rectus abdominis and mesentery. Left ovarian cyst was validated by pathological examination. There was no pathologic evidence showing the exact origin of her primary low-grade ESS on the peritoneum. The possible origin, which is believed to be either a metastasis or protopathic one, is discussed in our study.