The encapsulated papillary carcinoma of the thyroid. A morphologic subtype of the papillary thyroid carcinoma

Of a total of 182 papillary neoplasms, 25 lesions (average size, 3.1 cm) were classified on cytologic and histologic grounds as being encapsulated carcinomas. In eight of these tumors (32.2%) cervical lymph node metastasis and/or intraglandular lymphatic spread was observed. It was not possible to separate on histologic grounds those that did metastasize from those that did not. The excellent prognosis for the encapsulated variant of papillary thyroid carcinoma was confirmed by a long follow-up period in which no evidence of recurrences or further metastasis was registered as compared with the time of initial diagnosis, whatever the mode of therapy. On the basis of these findings, the encapsulated papillary carcinoma can be regarded as an early or slowly growing form of the papillary thyroid carcinoma.