Absence of peritumoral fibrosis or inflammatory infiltrate may be related to clinical progression of papillary thyroid microcarcinoma.

Rio Grande do Norte (RN) shows the highest relative incidence of papillary carcinomas in Brazil. To analyze histological features that might be associated with this incidence, the authors compared thyroid glands from 463 autopsies performed in RN with 427 surgical and autopsy glands previously studied in Sao Paulo (SP). The authors found 41 papillary thyroid microcarcinomas (PTMs) in 35 glands (8.