ODP593 Thyroid sarcoidosis: case study and literature review
Authors: Patadia Palak , Chalasani Varun , Hasan Farhad 
Published: November 2022

Abstract

Introduction
Sarcoidosis is a disorder characterized by noncaseating granulomas, most commonly in the lungs, lymph nodes, and skin. Patients often present with cough, skin or eye changes, enlarged lymph nodes, fatigue, or are found to have incidental findings on chest imaging. While any organ can be involved, thyroid involvement is rare, reportedly seen postmortem in 4.2 to 4.6% of sarcoidosis cases. We describe the case of a young adult male with thyroid sarcoidosis in addition to neurosarcoidosis.

Case Presentation
A 37-year old African American male was found to have a goiter on routine examination. Work up revealed an elevated TSH level of 11.1 uIU/mL (0.4-4. 0) with a free T4 of 0.91 ng/dL (0.7-1.9). Thyroid ultrasound demonstrated a dominant right-sided thyroid mass measuring 5.5×3.1×4.1 cm. Fine needle aspiration cytology reported polymorphic lymphocytes, few lymphohistiocytic aggregates, scant hurthle cells, and multinucleated giant cells. Thyroidectomy was recommended; intra-operatively the right thyroid lobe contained a 5-cm firm, hard, whitish mass in the mid inferior portion which could not be excised due to extensive fibrosis. Incisional biopsy was performed demonstrating fibrotic lymphocytic thyroiditis and non-caseating granulomas with no evidence of malignancy. He presented to the ER six weeks later with confusion, headaches, retro-orbital pain, and periodic involuntary movements in all extremities. MRI of the brain showed dural-based lesion in the right lateral and inferior temporal fossa. He underwent craniotomy and excisional biopsy of the lesion, which showed granulomatous inflammation, favoring a diagnosis of neurosarcoidosis. In a future admission, he was found to have dural venous sinus occlusion and new granulomas on brain MRI. It was then noted that previous thyroid biopsy revealed granulomatous disease, which was then linked to his sarcoidosis. He was discharged on prednisone and methotrexate with eventual further neurological complications.

Discussion
Thyroid sarcoidosis is very rare and because of this, it is frequently misdiagnosed initially and fine needle aspiration of the thyroid is frequently nondiagnostic. Histopathology is usually necessary to rule out malignancy and identify non-caseating granulomas. In some reported cases, thyroid sarcoidosis shared clinical, ultrasonographic, and even cytologic features with papillary thyroid cancer. Our case was unique for several reasons. Firstly, although not immediately noted, incisional thyroid biopsy was the first diagnostic clue of sarcoidosis. More commonly, patients are already diagnosed with systemic sarcoidosis. Additionally, typical findings such as mediastinal hilar adenopathy, hypercalcemia, and elevated angiotensin converting enzyme levels were absent. Although sarcoidosis of the thyroid is rare and often benign, it is important to consider this differential diagnosis while ruling out more likely causes as early detection can lead to early treatment and prevent adverse outcomes. The ideal treatment remains unclear, regarding whether to treat pharmacologically or concurrently with surgical intervention.
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