Thyroid carcinoma is a rare extraintestinal manifestation of colonic familial adenomatous polyposis (FAP). This syndrome is caused by germline mutations in adenomatous polyposis coli (APC) gene, on chromosome 5q21-q22. Many patients manifest various extracolonic features: upper gastrointestinal adenomas, congenital hypertrophic retinal pigment epithelial lesions, desmoids tumors, and thyroid, adrenal and brain cancers. It has been reported an incidence of 1.2% of thyroid carcinomas in FAP patients. We report a case of a female with this association.
Case presentation: A 43 year-old woman was seen for subclinical hypothyroidism. Her medical history was known for FAP. She underwent subtotal colectomy in 1995, and a colonic adenocarcinoma was found during pathologic study. Later genetics showed c.543546del in APC. Several intestinal obstructions led to abdominoperineal amputation and colostomy. In 2012, she required duodenoapancreatectomy since duodenal premalignant tumours were found. These surgeries had several postoperative complications and nowadays she suffers from short intestine syndrome with intermittent requirements of intravenous feeding. Also she had been operated for a desmoid tumor of abdominal wall and as teenager of posterior cranial fosa neuroblastoma that required chemo and radiotherapy.
Thyroid nodules were found in 2008 consulting for mild thyroid dysfunction. Neck exploration evidenced low grade goiter. Ultrasound imaging revealed multiple solid and cystic nodules. The biggest solid nodule and a calcified one were biopsied (large needle biopsy), results were not consistent with malignancy. Total thyroidectomy was proposed and performed in 2010. Pathologic description confirmed bilateral and multiple papillary carcinoma (no extrathyroidal extension). After that she underwent radioactive iodine ablation. Currently, the patient is treated with suppressive dose of levothyroxin and free of thyroid disease.
Conclusion: We present a case of a rare disease, FAP, with an extracolonic tumor, a papillary thyroid cancer. We asses the importance of early ultrasound exploration and surgical option if dubious results in these patients since the higher incidence of malignancy.