A case report of uncommon giant epidermal inclusion cyst found in the thyroid gland

Introduction and importance: This case report describes a rare occurrence of an epidermal inclusion cyst (EIC) being found in the thyroid gland and highlights the importance of considering uncommon entities like EIC in the differential diagnosis of thyroid lesions. Case presentation: A 68-year-old male presented with a large, painless swelling in the anterior neck, causing dysphagia and dysphonia. Imaging and cytology confirmed a benign Epidermal Inclusion Cyst involving the left lobe of the thyroid, which was successfully removed via hemithyroidectomy, resulting in resolution of symptoms. Clinical discussion: Epidermoid inclusion cysts are rare in the thyroid gland, with only sixteen reported cases worldwide. The cyst was diagnosed through ultrasound-guided fine needle aspiration and confirmed by surgical pathology. Treatment involves complete removal of the cyst and its capsule, which was successfully performed in this case under local anesthesia with sedation due to the patient’s medical history of COPD. Conclusion: it is important to consider the possibility of EIC when benign squamous cells are detected in a thyroid aspirate without any follicular cells. In such cases, hemithyroidectomy can be a successful management strategy.