TOPIC: Disorders of the Mediastinum TYPE: Medical Student/Resident Case Reports INTRODUCTION: Fallopian tube carcinoma is associated with a high rate of distant metastasis, likely due to the lack of florid symptoms. We describe a case of fallopian tube carcinoma, metastatic to mediastinal lymph nodes with cystic changes developing in the lymph nodes. CASE PRESENTATION: Our patient is a 65-year-old female with stage IIIA2 high-grade serous carcinoma of the fallopian tube diagnosed in 2019. She initially presented with lower extremity weakness, thought to be Guillain-Barré syndrome. She underwent MR spine, which was notable for a pelvic mass. PET-CT revealed hypermetabolic appearance of abdominal and mediastinal lymph nodes and a right lung nodule. She underwent surgical debulking of the pelvic mass, wedge resection of the right lung, and extensive lymph node dissection. This was followed by chemotherapy with carboplatin and paclitaxel. Final pathology reported a high-grade serous carcinoma of the fallopian tube. The right lung nodule was noted to be a histoplasma granuloma. She had a good response to the initial management. Approximately two years after initial diagnosis, the patient had rising CA-125 and subsequent imaging revealed new pulmonary nodules with enlarged necrotic appearing mediastinal and retroperitoneal lymph nodes. She was hesitant to start chemotherapy without confirmation of recurrence. She underwent endobronchial ultrasound (EBUS) with bronchoscopy, which confirmed enlarged mediastinal lymph nodes and biopsies were performed. The lymph node at the 4R station was 24mm in size with distinct cystic changes. Fine needle aspiration was performed, and it yielded 3ml of yellow-colored fluid. The final pathology showed high-grade adenocarcinoma of gynecologic origin with cells positive for PAX8, CK-7 and p53. The patient returned to the care of her oncologist to undergo further chemotherapy. DISCUSSION: Fallopian tube carcinoma is an uncommon gynecological malignancy, with very few reported cases of metastasis to the mediastinum. There is a limited understanding of the manifestations of the disease, especially regarding the characteristics of distant metastasis. Our patient had delayed recurrence of this cancer and imaging demonstrated distant metastasis to the mediastinal lymph nodes. We are presenting ultrasound characteristics of mediastinal lymph nodes in metastatic serous fallopian tube cancer with cystic changes and EBUS guided aspiration of fluid. After an extensive literature search, a case with similar findings was not found. CONCLUSIONS: Cystic changes in malignant lymph nodes are uncommon. This case demonstrates the importance of bronchoscopy and EBUS in the investigation of gynecological malignancies which are metastatic to the mediastinum. REFERENCE #1: Zhang B, Liu R, Li T, et al. Anterior mediastinal metastasis of primary fallopian tube adenocarcinoma: a case report. J Cardiothorac Surg. 2020;15(1):77. Published 2020 May 11. doi:10.1186/s13019-020-01111-4 DISCLOSURES: No relevant relationships by Zaid Ansari, source=Web Response No relevant relationships by Sharjeel Israr, source=Web Response No relevant relationships by Ashish Sadolikar, source=Web Response No relevant relationships by Ali Saeed, source=Web Response No relevant relationships by Hursh Sarma, source=Web Response No relevant relationships by Cindrel Tharumia Jagadeesan, source=Web Response