A Unique Presentation of Ectopic Thyroid Tissue: Case Report and Management Principles

Ectopic thyroid is a rare clinical presentation to encounter in day-to-day clinical practice. It occurs due to developmental defects in the early stages of the thyroid gland embryogenesis during its descent from the floor of the primitive foregut to its final pre-tracheal position. It is usually present along the extent of the thyroglossal duct as well as in distant locations such as sub-diaphragmatic or mediastinal spaces. The diverse clinical presentation of this rare entity often causes a diagnostic dilemma. A thyroid scintigraphy scan is pivotal in the diagnosis of ectopy, but ultrasonography is done more frequently. Surgical management is preferred for symptomatic cases, followed by radioactive iodine ablation and levothyroxine supportive therapy for refractory cases. We present a case of a 62-year-old female patient who presented with pain and swelling of the right submandibular region. On ultrasonography, a 5*4 cm firm mobile swelling of the right submandibular region was found, suggestive of right submandibular sialadenitis. Fine needle aspiration cytology (FNAC) was subsequently done, and it showed features of basaloid neoplasm like pleomorphic adenoma, and as the thyroid tissue was in an ectopic location, it must have been misdiagnosed. The patient was then taken up for right submandibular sialoadenectomy, and the histopathological examination of the operative specimen showed nodular colloidal goiter and mild chronic sialadenitis. Ectopic thyroid can present at various anatomical locations and thereby has varied clinical presentations which makes it a diagnostic dilemma for clinicians. The usual radiological investigations done include USG and CT scan, whereas thyroid scintigraphy is more precise in reaching the diagnosis of ectopic thyroid. The confirmatory diagnostic method is the histopathological examination of the excised specimen. Most cases of ectopic thyroid are asymptomatic and require regular follow-up. Symptomatic cases are managed by surgical excision followed by periodic monitoring and adequate thyroxine replacement.