Endocrine Abstracts

Introduction: Ectopic thyroid tissue is a rare developmental abnormality resulting from aberrant embryogenesis of the thyroid gland during its passage from the floor of the primitive foregut to its final pre-tracheal position. It may be the only functional thyroid tissue or may co-exist with normally located thyroid. Most of the cases are asymptomatic but symptoms related to location, size or function may occur. Possible malignancy potential has also been discussed.

Case report: The patient is a 52-year old women with nanism who was admitted to endocrinology department in November 2014. According to her past medical record at the age of 12 she was diagnosed with hypopituitarism (GH deficiency and hypogonadism) and hypothyroidism due to growth retardation, lack of pubertal development and marked delay in bone maturation. Treatment with Sotropin H and thyroidea siccata was started and continued until the age of 18 when final height of 130 cm was achieved. She had also been found to have microspherocytic hemolytic anemia and right renal hypoplasia since early childhood. On admission to our department she was in a good physical condition, family history was unremarkable but mild intellectual disability was observed. Laboratory tests found clinical hypothyroidism with TSH level of 17.8 mIU/l (0.34–5.60), FT4 was 9.7 pmol/l (7.86–14.40) without thyroid autoantibodies. The ultrasonography of the neck showed no thyroid tissue in the front pretracheal area. Two round-shaped soft tissue masses in the right and left submandibular area were seen. Subsequent technetium 99^m pertechnetate scan revealed three foci of tracer concentration in the left submandibular area with no activity at the usual site of the thyroid gland. A MRI of the head and neck showed multiple thyroid ectopy – below the hard palate, at the base of the tongue and just below the hyoid bone. Thyroid functional tests performed two weeks afterwards showed significant elevation of TSH up to 31.95 mIU/l and levothyroxine treatment was initiated.

Conclusion: Review of literature reveals only few cases of multiple thyroid ectopia reported so far. Although the molecular mechanisms involved in thyroid dysgenesis are not fully known, studies have shown that mutations in regulatory genes expressed in the developing thyroid could be responsible for the abnormal thyroid migration as well as congenital abnormalities in other organs as seen in our patient.