Pathological evaluation of differentiated thyroid cancer in patients with positive serum thyroglobulin and negative iodine scan

OBJECTIVE: There is no investigation that emphasizes the pathology of DTC (differentiated thyroid cancer) patients with positive Tg and negative iodine scan. The present study was performed to assess the pathology of these patients. MATERIALS AND METHODS: In this retrospective study, the records of 500 patients with differentiated thyroid cancer between June 2005 and November 2011 were assessed, and those patients who had elevated serum thyroglobulin (Tg) with a negative whole body I-131 scan (Tg+/WBS-) were included in the study. Patients were followed for clinical and pathological findings of thyroid cancer, including type, variant, local invasion and cervical lymph node metastasis, and serum Tg, TgAb, and TSH levels. RESULTS: A total of 38 patients, including 31 (81.6%) females and 7 (18.4) males with a mean age of 44.2 +/- 15.6 years (range, 14 to 77 yrs) took part in the study. All 38 patients had the papillary type of differentiated thyroid cancer (PCDTC), and none had the follicular type of differentiated thyroid cancer (FCDTC). For the variant type of PTC in 16 patients, it was found that 7 were classic type (43.8%), 7 were follicular type (43.8%), and 2 were tall cell (12.4%) for papillary thyroid cancer. In 22 patients no distinct variant had been reported. CONCLUSIONS: This report demonstrated that all of the 38 patients were PTC (100%), which is different from other previous studies. It may be concluded that the overall pathologic subtypes changes of DTC could mainly be due to the iodine fortification program in various geographic regions. The relationship between DTC pathologic subtypes and frequency of Tg+/WBS-condition was difficult to assess in this work. Therefore, further studies are required to evaluate this issue.