The clinical behavior of the follicular variant of papillary thyroid carcinoma (FVPTC) is similar to pure papillary thyroid carcinoma (PPTC) and completely different from follicular thyroid carcinoma (FTC).Design: Retrospective analysis of prospectively documented data.Setting: Referral center of a university hospital.Patients: Two hundred thirty-seven consecutive patients with follicular cell-derived thyroid carcinomas were operated on in our institution during a 15-year period, from January 1, 1980, to December 31, 1994. Of the 154 PTC patients, 37 (24%) had FVPTC. The mean follow-up was 128.2 months (10.7 years).Main Outcome Measures: Demographic features, tumor characteristics, local and distant spread, persistence or recurrence of disease, and carcinoma-related mortality were compared between the groups with FVPTC, PPTC, and non-Hü rthle cell FTC (NHFTC).Results: The frequency of multicentricity was significantly higher in the FVPTC group than in the PPTC group (P =.03) or in the NHFTC group (P =.01) (12 [32%] of 37 patients vs 17 [15%] of 117 patients vs 6 [10%] of 58 patients, respectively). The incidence of cervical lymph node metastases was lower in the FVPTC group than in the PPTC group (P = .30) and higher than in NHFTC group (P =.004) (12 [32%] of 37 patients vs 53 [45%] of 117 patients vs 6 [10%] of 58 patients, respectively). At diagnosis, no patient with FVPTC showed distant metastases, compared with 5 patients (4%) with PPTC (P=.34) and 19 (33%) with NHFTC (PϽ.001). There was no carcinoma-related death in the FVPTC group. The strikingly poorer prognosis for the NHFTC group was statistically significant (PϽ.001), whereas the difference in carcinoma-specific survival between the PPTC and the FVPTC groups did show a trend toward better survival in the FVPTC group. Conclusion:The clinical behavior of the FVPTC group did not differ significantly from that of the PPTC group, whereas compared with the NHFTC group, the FVPTC group showed statistically significant differences for most of the analyzed variables.

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In hereditary medullary thyroid carcinoma (MTC), recommendations regarding timing and extent of surgery are mainly based on the data of patients with the codon 634 RET mutation, which is the most often affected codon. Little is known about whether these recommendations may also be applied to patients with less common RET mutations. We ascertained the data from 140 patients with FMTC/MEN2A-related RET mutation not affecting codon 634 who have been treated at three specialized centers. The several RET mutations found affected codons 611 (n = 17), 618 (n = 22), 620 (n = 17), 768 (n = 9), 790 (n = 24), 791 (n = 21), 804 (n = 23), and 891 (n = 7). For each codon, the age of the youngest patient with MTC only (41, 7, 18, 29, 13, 47, 20, and 15 years, respectively), MTC with lymph node metastases (46, 24, 21, 34, 46, 47, 50, and 76 years, respectively), and MTC with distant metastases (52, 69, 43, 68, 57, - , - , and 75 years, respectively) was determined. All patients with lymph node metastases had elevated basal calcitonin levels. Based on these data, a more individual recommendation regarding timing and extent of surgery can be given. Because neither gender nor the type of nucleotide substitution for a specific codon appeared to have a significant influence on the age of onset, this recommendation should be based on the affected codon, the age of the patient, and the calcitonin level. Recurrent laryngeal nerve palsy (n = 6) and hypoparathyroidism (n = 3) were rather rare and were found only in patients older than 30 and 43 years, respectively, giving evidence that surgery in young patients can be performed safely.

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