Intro: Insular thyroid cancer is a rare and complex form of thyroid cancer, often referred to as poorly differentiated carcinoma. The exact incidence of insular thyroid cancers is difficult to assess due to controversial classification of this thyroid cancer over the years. It is termed poorly differentiated as it falls between the well-differentiated and undifferentiated carcinomas both morphologically and biologically[1]. Case: A 41 year old Hispanic female, with a history of prolactinoma and hyperparathyroidism, presented to the hospital with 10 days of progressive lower extremity weakness and paresthesias from T4 downwards, inability to bear weight, and no bowel movement for 12 days. MRI revealed a large thoracic soft tissue mass (7x4x4cm) centered in the posterior and medial aspect of the chest wall at T4-T5 with involvement of the spinal cord and vertebral bodies. She was also found to have a right sided thyroid mass (4.5x5x4 cm) with tracheal deviation- HerThyoid function test, were normal Intact PTH was 261, Thyroglobulin over 300, and Thyroid Antibodies were negative. Patient underwent T3-T6 laminectomy, T2-T7 fusion, and T4-T5 tumor resection, which was subtotal due to vascularity. Second procedure included a right thoracotomy, chest wall resection of ribs 4 and 5 with full resection of paraspinal mass, total thyroidectomy, parathyroidectomy with central cervical lymphadenectomy. Pathology results of paraspinal mass showed insular thyroid carcinoma. Post operatively, the patient reported improvement of sensation and strength in lower extremities. Genetic testing for MEN syndrome was negative. Discussion: Insular thyroid carcinoma, also referred to as poorly differentiated carcinoma is a rare form of thyroid cancer. Insular carcinoma was characterized by to include the following complex histologic features, “formation of solid clusters (insulae) of tumor cells containing a variable number of small follicles; variable but consistently present mitotic activity, capsular and blood vessel invasion; and frequent necrotic foci, sometimes leading to formation of peritheliomatous patterns”[1]. The cells originate from follicular epithelium and possess the potential to concentrate radioiodine[2]. Unlike anaplastic carcinoma of the thyroid, p53 and p21 staining was negative in insular carcinomas[3]. Thyroglobulin staining is generally positive[4]. Distant metastasis occurs in about 31% of patients with insular thyroid carcinoma[5]. In cases of distant metastasis, treatment with thyroidectomy and radioiodine therapy were shown to independently improve survival[5]. The Constellation of Insular thyroid cancer, hyperparathyroidism and Prolactinoma, has not been reported before. References: [1]. Am J Surg Pathol. 1984;8:655- [2] J of Nuc Med 32(7), 1358 [3] Ann of Surg vol. 231,3 (2000): 329 [4] JCEM 99. 1167–9. 10.1210/jc.2014 [5] Cancer. 2012 Jul;118(13) 3260

Introduction: Thyrotoxicosis in pregnancy presents the challenge of maintaining a normal level of maternal free thyroid hormone, while minimizing adverse drug effects, obstetric complications, and the risk fetal hypothyroidism. Propylthiouracil is used for treatment in the first trimester with thyroidectomy typically performed in the second trimester if PTU/ MTZ are intolerable or if thyrotoxicosis persists. When thyroidectomy is indicated, thyroid hormone levels must be normalized prior to the operation, as there is risk of thyroid storm that can occur during and up to several hours postoperatively. In such cases, preoperative plasmapheresis may be considered. Case Presentation: We present a 24 year old G2P0101 Hispanic female who reported to the ED with throat pain, chills, tachycardia, and shortness of breath who was found to have a TSH less than 0.005, free T4 3.15, elevated alkaline phosphatase, and an incidentally discovered early pregnancy approximately 4 - 6 weeks gestation. Medical history includes hyperthyroidism with over ten hospitalizations for thyrotoxicosis within the last three years and preterm delivery during her first pregnancy. A recent thyroid biopsy in 2017 showed a benign multinodular goiter. She had been taking methimazole and current CT of the neck demonstrated marked thyroid goiter with mild tracheal narrowing and mild tonsillitis. She was discharged on propylthiouracil 100 mg TID, metoprolol 25 mg TID, and augmentin 875 mg BID with the goal of decreasing her free T4 and T3 in preparation for thyroidectomy. Four days later, the patient returned to the ED with similar symptoms. Labs revealed TSH 0.001, free T4 3.70, FreeT3 15.1 WBC 3.1, platelets 103, and elevated total bilirubin, transaminases, and alkaline phosphatase. EKG demonstrated sinus tachycardia with minimal diffuse ST depression. Ultrasound showed a 0.34 cm round hypoechoic focus in the endometrial cavity without a fetal pole or cardiac activity. Chest X-ray demonstrated minor bibasilar atelectasis. The patient was admitted and PTU was discontinued due to leukopenia and elevated transaminases. Dexamethasone was started and metoprolol was continued. Total thyroidectomy was planned for when free T4 less 2.0 The patient received two treatments of plasmapheresis, which decreased free T4 to 2.11 and then to 1.40. The thrombocytopenia and transaminitis resolved A total thyroidectomy was performed and well tolerated. patient had full term pregnancy, uneventful delivery while on thyroid hormone replacement. Conclusion : Preoperative plasmapheresis can be considered for the normalization of free T4 if thionamides fail or cannot be tolerated. This case demonstrates the successful management of thyrotoxicosis with plasmapheresis in the first trimester of pregnancy.to Our knowledge Plasmapheresis was not used before in Pregnancy in preparation for thyroidectomy.