Thyroid Gland - Cyst, Congenital

Thyroid gland - Cyst, Congenital in a female F344 rat from a chronic study. An enlarged follicle is present (arrow).
Figure 1 of 4

Thyroid gland - Cyst, Congenital in a female F344 rat from a chronic study. Higher magnification of the enlarged follicle in Figure 1 shows the ciliated epithelium lining part of the follicle.
Figure 2 of 4

Thyroid gland - Cyst, Congenital in a male B6C3F1 mouse from a chronic study. A cystic follicle containing keratinized material is present.
Figure 3 of 4
comment:
Cysts found in the thyroid and adjacent parathyroid represent embryonal rests and may be lined by flattened or ciliated epithelium ( Figure 1



recommendation:
Congenital cysts should be diagnosed whenever present. Grading of cysts is not necessary unless the pathologist feels grading would highlight a treatment effect.references:
Hardisty JF, Boorman GA. 1990. Thyroid gland. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 519–536. Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563
Hardisty JF, Boorman GA. 1999. Thyroid and parathyroid glands. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 537–554. Abstract: http://www.cacheriverpress.com/books/pathmouse.htm
Web page last updated on: August 08, 2014