THYROID-CANCER IN PATIENTS WITH FAMILIAL ADENOMATOUS POLYPOSIS

The association between thyroid cancer and familial adenomatous polypo sis (FAP), albeit rare, is well known. Ht has been suggested that the thyroid tumors have unique histologic characteristics and mag be folli cular in origin. Because of their rarity, treatment and long-term prog nosis are uncertain. Twelve such patients (prevalence 399/100,000) see n during 1949-1995 were retrospectively reviewed. Histology was indepe ndently re-reviewed by two pathologists. There mere 11 female patients (two sisters) and 1 male patient, with a mean age of 28 years (range 15-61 years). Eight patients (66%) had multicentric tumors and five (4 2%) bilateral disease. Average tumor diameter was 1.8 cm (range 0.2-5. 0 cm). Regional nodal metastases Here present in two patients. All 12 thyroid cancers in this series were papillary. The one male patient de monstrated ''typical'' histology with variable papillary and follicula r architecture, whereas the 11 female patients had tumors with unusual histology as described by Harach. Five patients (41%) were treated by total thyroidectomy, five with near-total thyroidectomy, and two with lobectomy alone. Mean follow-up was 142 months (range 7 months to 30 years). Regional recurrent disease occurred in two patients, one of wh om died of the disease. The 5- and 20-year survivals mere 90% and 77%, respectively. The results indicated that all tumors in this study mer e papillary, although atypical histology was encountered in 91%. The m ean age (28 years) is younger than that of patients with sporadic dise ase. Multicentricity and bilateral disease are common. In view of this finding, total thyroidectomy should be strongly considered. Long-term prognosis is excellent. The finding of unusual histology in a young p atient with papillary thyroid carcinoma should arouse the suspicion of FAP.