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Oral Mucosa, Gingiva - Ectopic Tissue

Image of ectopic tissue in the oral mucosa gingiva from a male F344/N rat in a chronic study
Oral mucosa, Gingiva - Ectopic tissue, Sebaceous gland in male F344/N rat from a chronic study. There are clusters of sebaceous glands in the gingiva.
Figure 1 of 4
Image of ectopic tissue in the oral mucosa gingiva from a male F344/N rat in a chronic study
Oral mucosa, Gingiva - Ectopic tissue, Sebaceous gland in male F344/N rat from a chronic study (higher magnification of Figure 1). The clusters of sebaceous glands in the gingiva are adjacent to a dilated duct.
Figure 2 of 4
Image of ectopic tissue in the oral mucosa gingiva from a male F344/N rat in a chronic study
Oral mucosa, Gingiva - Ectopic tissue, Sebaceous gland in male F344/N rat from a chronic study. There are clusters of sebaceous glands in the gingiva.
Figure 3 of 4
Image of ectopic tissue in the oral mucosa gingiva from a male F344/N rat in a chronic study
Oral mucosa, Gingiva - Ectopic tissue, Sebaceous gland in male F344/N rat from a chronic study (higher magnification of Figure 3). The clusters of sebaceous glands in the gingiva appear to feed into a dilated duct.
Figure 4 of 4
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comment:

Ectopic sebaceous glands in the oral cavity are also known as Fordyce’s granules. Histologically, these are a collection of sebaceous glands unassociated with hair follicles ( Figure 1image opens in a pop-up window , Figure 2image opens in a pop-up window , Figure 3image opens in a pop-up window , and Figure 4image opens in a pop-up window ). The glands in the molar gingiva are often associated with cystically dilated ducts filled with sebum. In one NTP study examining 734 male and 722 female F344 rats, Fordyce’s granules were very common in the midsagittal gingiva of the upper incisor in males and increased in incidence with age (34.2%, 50%, and 56.3% in 26-week, 65-week, and 2-year studies, respectively). Ectopic sebaceous glands were rare in females (0%, 0%, and 2.8% in 26-week, 65-week, and 2-year studies, respectively). Ectopic sebaceous glands of the molar gingiva were very rare in both sexes. Ectopic sebaceous glands are often not noticeable on gross examination and are considered an incidental finding.

recommendation:

This finding should be diagnosed as "Oral mucosa, gingiva - ectopic tissue, sebaceous gland." No grade is necessary.

references:

Imaoka M, Satoh H, Kai K, Kajimura T, Furuhama K. 2003. Spontaneous ectopic sebaceous glands (Fordyce’s granules) in the oral mucosa of Sprague-Dawley rats. J Toxicol Pathol 16:253-257.
Abstract: http://ci.nii.ac.jp/naid/10025851222

Yoshitomi K, Brown HR, Eustis S. 1990. Fordyce's granules of the incisor and molar gingival in F344 rats. Vet Pathol 27:432-438.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/2278131

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