Lacrimal Gland - Metaplasia, Harderian

Image of metaplasia, harderian in the lacrimal gland from a male Osborne Mendel rat in a chronic study
Lacrimal gland - Metaplasia, Harderian in a male Osborne-Mendel rat from a chronic study. Metaplasia, Harderian (arrow) is characterized by a focus of tubules resembling Harderian gland alveoli.
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Image of metaplasia, harderian in the lacrimal gland from a male Osborne Mendel rat in a chronic study
Lacrimal gland - Metaplasia, Harderian in a male Osborne-Mendel rat from a chronic study (higher magnification of Figure 1). Metaplasia, Harderian (arrow) is characterized by tubules lined by cuboidal cells with pale, foamy to vacuolated cytoplasm resembling Harderian gland alveoli.
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comment:

Clusters of tubules lined by cuboidal cells with pale, foamy to vacuolated cytoplasm (resembling Harderian gland alveoli) can occur in the lacrimal glands of rats and mice, especially rats ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ). This “harderization” is more prominent in the exorbital lacrimal gland (the lacrimal gland usually sampled for histology) than in the intraorbital lacrimal gland. Incidence and severity of this change increase with age, and it is more common and extensive in male than in female rats. The increased Harderian gland–type development in the lacrimal glands of male versus female rats is one feature of the prominent sexual dimorphism of this tissue in this species. In mice, this change appears to be more frequent in females than in males. The metabolic and functional characteristics of these cells have not been characterized, and it is unknown whether this represents a true metaplastic or a degenerative change.

recommendation:

This finding should be diagnosed as "lacrimal gland - metaplasia, Harderian" and assigned a severity grade. It should be diagnosed only if there are treatment-related differences in incidence and/or severity. "Ectopic Harderian gland" and "ectopic tissue" are considered inappropriate terms because they suggest a developmental anomaly.

references:

Cornell-Bell AH, Sullivan DA, Allansmith MR. 1985. Gender-related differences in morphology of the lacrimal gland. Invest Ophthalmol Vis Sci 26:1170-1175.
Abstract: http://www.iovs.org/content/26/8/1170.short

Gaertner DJ, Lindsay JR, Stevens JO. 1988. Cytomegalic changes and "inclusions" in lacrimal glands of laboratory rats. Lab Anim Sci 38:79-82.
Abstract: http://ebm.sagepub.com/content/101/1/164.short

Geiss V, Yoshitomi K. 1999. Eyes. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 471-489.
Abstract: http://www.cacheriverpress.com/books/pathmouse.htm

Krinke AL, Schaetti PR, Krinke GJ. 1994. Changes in the major ocular glands. In: Pathobiology of the Aging Rat, Vol 1 (Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM, eds). International Life Sciences Institute Press, Washington, DC, 109-119.

Krinke GJ, Schaetti PR, Krinke A. 1996. Nonneoplastic and neoplastic changes in the Harderian and lacrimal glands. In: Pathobiology of the Aging Mouse, Vol 2 (Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM, eds). International Life Sciences Institute Press, Washington, DC, 139-152.

National Toxicology Program. 1990. NTP TR-376. Toxicology and Carcinogenesis Studies of Allyl Glycidyl Ether (CAS No. 106-92-3) in Osborne-Mendel Rats and B6C3F1 Mice (Inhalation Studies). NTP, Research Triangle Park, NC.
Abstract: http://ntp.niehs.nih.gov/go/8892

Percy DH, Wojcinski ZW, Schunk MK. 1989. Sequential changes in the Harderian and exorbital lacrimal glands in Wistar rats infected with sialodacryoadenitis virus. Vet Pathol 26:238-245.
Full Text: http://vet.sagepub.com/content/26/3/238.full.pdf

Sashima M, Hatakeyama S, Satoh M, Suzuki A. 1989. Harderianization is another sexual dimorphism of rat exorbital lacrimal gland. Acta Anat 135:303-306.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/2801002

Tier H. 1949. On the sizes of the nuclei in the glandula infraorbitalis of the white rat. Acta Pathol Microbiol Scand 26:620-625.
Abstract: http://onlinelibrary.wiley.com/doi/10.1111/j.1699-0463.1949.tb00761.x/abstract

Walker R. 1958. Age changes in the rat’s extraorbital lacrimal gland. Anat Rec 132:49-69.
Abstract: http://onlinelibrary.wiley.com/doi/10.1002/ar.1091320104/abstract

Yoshitomi K, Boorman GA. 1990. Eye and associated glands. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, CA, 239-260.
Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563