SUN-276 Neurofibromatosis Type 1 Associated with Ovarian Cancer and Multinodular Goiter

Abstract Disclosure: J. Prim: None. V.Q. Mai: None. Background: Neurofibromatosis Type 1 (NF1) is an inherited neurocutaneous disorder caused by mutations in the neurofibromin gene on chromosome 17. Clinical manifestations of NF1 include the development of neurofibromas, gliomas, and malignant peripheral nerve sheath tumors. We report a rare case of the simultaneous development of ovarian carcinoma and nodular thyroid disease in a patient with NF1.Case Presentation: A 64-year-old woman with a history of NF1 presented for evaluation of thyroid nodules found incidentally on CT imaging. Her medical history was significant for a recent diagnosis of high grade serous ovarian carcinoma for which she had undergone total abdominal hysterectomy, bilateral salpingo--oophorectomy, omentectomy and tumor debulking, and was undergoing chemotherapy with carboplatin and paclitaxel. Previous genetic testing confirmed a pathogenic full gene deletion of NF1 with no other identified mutations known to be associated with gynecologic or thyroid neoplasm risk. Physical exam showed skin freckling, café au lait spots, cutaneous neurofibromas, and palpable left and right-sided thyroid nodules. Thyroid ultrasound confirmed 3 dominant nodules including a 1.3 x 0.8 x 1.1cm solid, hypoechoic LUL nodule; a 2.4 x 2.6 x 2.6cm mixed cystic and solid, isoechoic LLL nodule; and a 3.2 x 2.2 x 3.4cm solid, isoechoic RLL nodule. TSH level was normal. FNA showed nondiagnostic cytology for the LUL thyroid nodule and benign cytology for the LLL and RLL nodules. Discussion: The NF1 gene regulates the Ras oncogene cellular signal transduction pathway with effects on cell growth, division, and survival. There is increasing recognition that the overactive intracellular signaling characteristic of NF1 predisposes to neoplasms of many organs, including an increased risk of benign and malignant neoplasms of the endocrine system. Cases of ovarian serous carcinoma in patients with NF1 are rare, occurring in only 0.5% of patients with NF1 in one large cohort study. However, molecular analysis of tumors identified NF1 mutations in 22% of cases of serous ovarian carcinoma, implicating a role of Ras pathway activation in the pathogenesis of this type of malignancy. Nodular thyroid disease has also been described in NF1, including papillary thyroid cancer. This case study adds to the growing literature identifying cases of neoplastic disease not previously commonly associated with NF1. These findings support the concept that patients with NF1 should be monitored for the development of cancers of endocrine tissues. Presentation: Sunday, July 13, 2025