Objective: To study the clinical course of patients with the encapsulated variant of papillary thyroid carcinoma, in which there is a well-defined fibrous wall completely separating the tumour cells from the adjacent tissue.
Design: Retrospective review.
Setting: University hospital, Spain.
Subjects: Of a total of 163 patients whose papillary thyroid carcinomas were treated surgically between 1975 and 1985, there were 25 encapsulated tumours.
Main outcome measures: Clinicopathological features and survival rate compared with those of non-encapsulated papillary thyroid carcinomas.
Results: Mean follow up was 9 years (range 7-17), and 42 were excluded because follow up was incomplete. Encapsulated tumours differed from the earlier age of other types in that they presented earlier (mean age 36 years compared with 45), they were significantly less likely to have symptoms of compression (1/25 compared with 24/96, p = 0.024), or nodal metastases (3/25 compared with 43/96, p = 0.002), or to recur (0/25 compared with 33/96, p = 0.002). No patients died in the encapsulated group compared with 11/96 in the other group.
Conclusions: Encapsulated papillary carcinomas have an excellent prognosis, and can be cured by operation.