[Relationship between solid cell nests and focal lymphocytic thyroiditis]

Considering the fact that there is often a combined occurrence of focal lymphocytic thyroiditis (FLT) and so-called Solid Cell Nests (SCN) in the same human thyroid gland, we examined thyroid tissue of 500 routine autopsies. SCN were found in 56 (11.2%) and FLT in 59 (11.8%) patients. The combination of these two lesions was encountered in 18 (3.6%) cases. This incidence (3.6%) is four to five times higher than would be expected from chance alone. In 12 of the 18 patients mentioned, SCN were in close association with lymphocytic infiltration, but this was not statistically significant. Two hypotheses are discussed concerning the combination of SCN and FLT. According to Klinck and Menk (1951), the SCN, derived like the epithelial part of the thymus from the embryologic pharyngeal pouch, forms a favorable micro-environment for inflammatory cells. Based on the second hypothesis, the SCN, probably a remnant of the ultimobranchial body, mark an incompletely developed thyroid. These thyroids would be predisposed to auto-immune thyroid disease such as FLT.