Occult micro medullary thyroid carcinoma: Therapeutic strategy and follow-up

Twenty micro medullary thyroid carcinomas (MTCs) were found in histologic s pecimens of 19 patients in our department from 1990 to 1998. There mere 14 women and 5 men, with a median age of 63 Sears. The indication for surgery was goiter in 12 patients and a solitary nodule in 7 patients (three differ entiated cancers). Altogether, 18 patients had unifocal micro-MTCs with a m edian diameter of 3.6 mm. One patient had a bilateral MTC (3 and 5 mm, resp ectively). Surgical procedures consisted of 9 total thyroidectomies and 10 lobectomies or subtotal thyroidectomies. Of these 10 patients, 4 underwent reoperation (totalization). One was operated on 48 months after a positive pentagastrin test: There was no thyroid residual tumor hut three lymph node micrometastases. Among the six patients in whom thyroid tissue was left, a 91-year-old woman died of unrelated cause and the five others remain disea se-free without biologic abnormalities at follow-ups of 18 to 70 months. Co nsidering the aggressiveness of MTCs, total thyroidectomy with central comp artment dissection is theoretically indicated. However, among the nine tota l thyroidectomies and four secondary totalizations associated with at least central compartment dissection, no other thyroid lesion was observed and o nly one case of lymph node microinvasion was found. Because of the morbidit y associated with reoperation and neck dissection, we propose that it is in dicated only for microcarcinomas > 5 mm in diameter, in cases of an abnorma l response to pentagastrin, or when it is difficult to ensure prolonged fol low-up of the patient.