Prognostic importance of sclerosing variant in papillary thyroid carcinoma

The diffuse sclerosing variant (DSV) of papillary thyroid carcinoma is known for its high aggressiveness, high incidence of lymph node metastases, and high incidence of pulmonary metastases, and thus its consequently poorer prognosis. In this study, we undertook a retrospective analysis of papillary thyroid carcinomas to assess whether DSV can be considered a predictive factor for prognosis. We performed a retrospective evaluation of the Department's database of patients with papillary thyroid carcinoma who had undergone total thyroidectomy from January 1992 to December 2000. Group I consisted of 83 DSV patients and Group II was 168 pure papillary carcinoma (PC) patients. A significant prevalence of multinodular thyroid disorder on diagnosis was found for PC (P < 0.05), whereas with DSV, there was a significantly higher prevalence of post-thyroiditis nodular thyroid disorder than with PC (P < 0.001). The incidence of laterocervical lymph node pathology on diagnosis was significantly higher for DSV (P < 0.05). In 3.6 per cent of PC patients and 15.7 per cent of DSV patients, we observed recurrences in the regional lymph nodes (P < 0.001). We found 1.2 per cent distant metastases in PC patients and 7.2 per cent in DSV patients (P < 0.05). One PC patient (0.6%) and three DSV patients (3.6%) died of tumor-related causes (P < 0.05). Our study demonstrated that diffuse sclerosing carcinoma leads to a poorer prognosis to the extent that its classification as an autonomous clinical pathological entity is justified. In conclusion, we can state that DSV is a form of papillary thyroid tumor characterized by its higher aggressiveness, diffuse intrathyroid growth, and high incidence of lymph node and pulmonary metastasis. Ultimately, this means a poorer prognosis. In the presence of risk factors indicating a possible increase in biological aggressiveness, adequate postoperative treatment and close follow-up become essential.