Resistance to thyroid hormone (RTH) is an autosomal dominant hereditary disorder that is difficult to diagnose because of its rarity and variable clinical features. The magnitude of RTH is caused by mutations in the thyroid hormone receptor beta (TRbeta) gene. We recently treated a 38-yr-old woman with RTH who had incidental papillary thyroid carcinoma. She presented with goiter and displayed elevated thyroid hormone levels with an unsuppressed TSH. She was determined to harbor a missense mutation of M310T in exon 9 of the TRbeta gene, and diagnosed with generalized RTH. This mutation has not yet been reported in Korea. RTH is very rare and easily overlooked, but should be considered in patients who present with goiter and elevated thyroid hormone levels with an unsuppressed TSH. The association between thyroid cancer and RTH needs further study.
Adult ; Diagnosis, Differential ; Exons ; Female ; Humans ; Mutation, Missense ; Thyroid Gland/radionuclide imaging ; Thyroid Hormone Receptors beta/genetics ; Thyroid Hormone Resistance Syndrome/complications/*diagnosis ; Thyroid Hormones/blood ; Thyroid Neoplasms/*complications/genetics/ultrasonography

Cowden syndrome is an uncommon, autosomal dominant disease which is characterized by multiple hamartomas of the skin, mucous membrane, brain, breast, thyroid, and gastrointestinal tract. The diagnosis of Cowden syndrome implicates an increased risk of developing breast cancer. We report a case of a 22-year-old woman with Cowden syndrome that presented as breast cancer with concomitant bilateral exuberant benign masses in both breasts.
Arteriovenous Malformations/radiography ; Breast Neoplasms/*complications/*diagnosis/ultrasonography ; DNA/analysis ; DNA Mutational Analysis ; Diagnosis, Differential ; Female ; Hamartoma Syndrome, Multiple/*complications/*diagnosis/genetics/ultrasonography ; Humans ; PTEN Phosphohydrolase/genetics ; Thyroid Neoplasms/radiography ; Tomography, X-Ray Computed ; Young Adult