Intrathyroidal ectopic thymic tissue may mimic thyroid cancer: a case report

Abstract

Ectopic intrathyroidal thymus tissue that may be present as a thyroid nodule is rarely reported. We present a case of a 4-year-old boy with a solitary thyroid nodule. Real-time thyroid ultrasound showed a calcified nodule in the right lobe. Complete blood count, serum calcitonin, and thyroglobulin concentration were normal and antithyroid antibodies were negative. Fine-needle aspiration (FNA) biopsy was revealed as inadequate for cytological examination. During his follow-up, nodular enlargement was found, and the patient was subjected to surgical total excision of the right lobe of the thyroid gland. Pathological examination showed an ectopic intrathyroidal thymus tissue. In childhood, ectopic intrathyroidal thymus tissue can present as an enlarging microcalcified thyroid nodule that may mimic thyroid cancer and may grow during follow-up.

Prevalence of Ectopic Intrathyroidal Thymus in Japan: The Fukushima Health Management Survey

“…Although ectopic intrathyroidal thymus has recently been reported in children, it is thought to be uncommon and can be misdiagnosed as a thyroid tumor, resulting in unnecessary surgery (5)(6)(7)(8)(9)(10)(11). To date, few reports have studied the prevalence of ectopic intrathyroidal thymus on a large scale.…”

Concurrent intrathyroidal thymus and parathyroid in a patient with papillary thyroid carcinoma: a challenging diagnosis

“…All lesions were located in the right lobe of the thyroid, with imaging examinations not being able to differentiate between them, as findings consistent with either possible diagnosis were present (6). Eventually, diagnosis was established through histologic examination of the surgically excised tissue.…”

Acoustic Radiation Force Impulse Imaging in the Differential Diagnosis of an Ectopic Intrathyroidal Thymus

“…Ectopic parathyroid gland, esophageal diverticula, lymphocytic thyroiditis, adenoma, nodular goiter, lymphoma and abscess are some of the lesions, which should be considered in the differential diagnosis of nodular thyroid lesions in children. Although rare, ectopic intrathyroidal thymus is one of the possible origins of a nodular lesion in the thyroid gland and several cases of intrathyroidal ectopic thymus in children had previously been reported [4,5].…”