Introduction: The ectopic thymus tissue (ETT) represents a migration and descending deficiency of the organ during embryogenesis.
HMWK have a strong positive reaction in normal anatomical localized thymus and thymomas. A similar reaction pattern is seen in thyroid solid cell nests (SCNs) suggesting that these cells share a common origin with thymic tissue. Moreover, can be very helpful in differentiate CASTLE from other thyroid tumors.
Our aim was to investigate the expression of CK34βE12 in the normal ectopic thymic tissue which was not yet described.
Materials and methods: We analyzed 5 cases of ETT, from female patients with age between 14 and 49 years, 2 intrathyroidal and 3 adjacent to thyroid and parathyroid. The tissue was incidentally discovered in patients with diverse thyroid and parathyroid pathology.
Slides of paraffin-embedded specimens were HE stained and the immunohistochemical investigation used monoclonal antibodies against HMWK, clone 34βE12 (Dako).
Results: The thymic tissue was microscopically identified inside and adjacent to thyroid and parathyroid. In one case, within the thyroid were identified areas of SCNs. Also in one case ETT had the appearance of partial involution. In the intrathyroidal ETT, we observed an intense positive reaction for CK 34βE12 with strong, granular pattern, in the epithelial cells of the subcapsular region, medullar areas and Hassall corpuscles. In the ETT adjacent to thyroid the intensity of reaction was smaller. The lower intensity was seen in the partial involution thymus.
Conclusions: Our results suggest that might be difference of CK34βE12 expression in the ectopic cervical thymic tissue according with the location and age.
30 Apr - 04 May 2011
European Society of Endocrinology