Pleural Metastasis of High-Grade Endometrial Stromal Sarcoma With YWHAE Gene (17p13.3) Rearrangement, A Rare Case Report

Introduction/Objective Endometrial stromal sarcoma (ESS), a rare malignant neoplasm of endometrial stroma, accounts for less than 1% of all uterine tumors. High grade ESS (HGESS) is aggressive and commonly relapses even after surgical and neoadjuvant therapy. Abdominal and pelvic regions are common sites of metastasis, however, distant metastases to the liver, lung, vertebrae, and brain have been reported. Methods/Case Report We encountered a 49-year-old female who presented with shortness of breath, found to have a left pleural effusion and multiple pleural masses. She initially presented three years ago with heavy irregular menses and left pelvic pain for one year. D&C revealed prominent small spindle cells for which a stromal nodule and low-grade or malignant process was probable. CT scan showed an enlarged uterus. Hysterectomy with bilateral salpingo- oophorectomy, bilateral pelvic and para-aortic lymph node dissection, and partial omentectomy were performed. The uterus revealed an intramural 7 cm mass with a serpiginous growth pattern and lymphovascular invasion. Tumor cells were plump to spindled with areas of high cellularity, rounded nuclei, increased atypia and mitosis. Atypical areas were positive for cyclin D1, focally positive for CD10, and negative for ER, PR, SMA, desmin, AE1/3 and CAM5.2. FISH studies showed rearrangement of YWHAE gene (17p13.3) and no rearrangement of JAZF1 or PHF1 gene regions. Findings supported the diagnosis of HGESS. The patient received post-operative chemotherapy. Biopsy of the current pleural lesion revealed a nonspecific malignant spindle cell neoplasm positive for BCL1, CD56, CD117, CD99, TLE1 and INI1, while negative for AE1/3, CAM5.2, EMA, ER, PR, CK5/6, calretinin, SMA, desmin and S100. The CD10 stain was inconclusive. FISH studies showed rearrangement of YWHAE gene (17p13.3) and no rearrangement involving JAZF1 or PHF1 gene regions. No rearrangement of the SS18 gene region was observed and synovial sarcoma was excluded. Overall findings support the diagnosis of metastatic HGESS. Results (if a Case Study enter NA) NA Conclusion HGESS, a rare tumor with a nonspecific immunostain profile, has the ability to metastasize to rare body sites, such as the pleura in our case. Display of spindle cell morphology is a nonspecific finding that raises broad differential diagnoses. In women, with or without a history of uterine neoplasm, HGESS is a clinically worthwhile diagnosis to be mindful of.