Your browser does not support JavaScript or has JavaScript turned off. The Atlas functions best with JavaScript enabled but may used without JavaScript.

Thyroid Gland, Follicle - Dilation

Image of follicle dilation in the thyroid gland from a male B6C3F1 mouse in a chronic study
Thyroid gland, Follicle - Dilation in a male B6C3F1 mouse from a chronic study. There is a single dilated follicle (arrow).
Figure 1 of 4
Image of follicle dilation in the thyroid gland from a male B6C3F1 mouse in a chronic study
Thyroid gland, Follicle - Dilation in a male B6C3F1 mouse from a chronic study. This higher magnification of Figure 1 shows the flattened epithelium lining the dilated follicle.
Figure 2 of 4
Image of follicle dilation in the thyroid gland from a male F344/N rat in a chronic study
Thyroid gland, Follicle - Dilation in a male F344/N rat from a chronic study. There is dilation of several adjacent follicles.
Figure 3 of 4
Image of follicle dilation in the thyroid gland from a male F344/N rat in a chronic study
Thyroid gland, Follicle - Dilation in a male F344/N rat from a chronic study. Higher magnification of Figure 3 shows the flattened epithelium of the dilated follicles and pigmented macrophages in one of the follicles (arrow).
Figure 4 of 4
next arrow

comment:

One or more dilated follicles occur as a common and age-associated change in mouse and rat thyroids. Affected follicles may have pale ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ) or absent colloid, and exfoliated cells may be present in the lumen. The dilated follicles are frequently seen at the periphery of the thyroid gland ( Figure 3image opens in a pop-up window and Figure 4image opens in a pop-up window ). Dilated follicles are lined by low cuboidal to flattened epithelium.

recommendation:

Documentation and grading of dilated follicles are recommended. The diagnosis should indicate whether the dilation is bilateral, with a severity grade based on the more severely affected thyroid gland. The presence of cells within the lumens of the dilated follicles need not be diagnosed separately unless warranted by severity.

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

NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.