Adrenal Gland - Amyloid
comment:The term "amyloid" classically denotes various insoluble, fibrillar proteins that share a similar configuration (β-pleated sheets). These abnormally folded proteins form and accumulate intra- and extracellularly in many tissues due to many causes, such as genetic predisposition and local and systemic inflammation of various etiologies. In rats, focal or generalized amyloid deposition rarely occurs in any tissue, including the adrenal gland. In mice, amyloid deposition in the adrenal gland and other tissues is overall far more common. There are genetically related differences in incidence, with very low incidences in some strains, such as the B6C3F1/N mouse, and much higher incidences in other strains, such as (Swiss) CD-1 and Swiss Webster mice. In mice, amyloidosis is usually a spontaneous, age-related systemic disease, with the adrenal gland one of the more commonly affected tissues. Severity (amount of amyloid/tissue) also tends to increase with age in all tissues, including the adrenal gland. In mice, adrenal amyloid deposition usually first appears as small clumps between cells of the inner cortex, with progressive centripetal extension into the outer cortex (zona fasciculata) ( Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , and Figure 6 ). The amyloid proteins can form large, expansile aggregates ( Figure 1 and Figure 2 ), which distort the normal architecture and can eventually coalesce into thick circumferential bands that surround the medulla ( Figure 3 and Figure 4 ). The amyloid may extend into the medulla or zona glomerulosa, but these regions are generally unaffected.
With hematoxylin and eosin (H&E) stain, amyloid deposits appear as homogeneous, amorphous, pale eosinophilic material ( Figure 1 , Figure 2 , Figure 3 , and Figure 4 ). Special histochemical stains are often used to distinguish amyloid from fibrous connective tissue, fibrin, and other substances. One of the most widely used stains is Congo red. Amyloid stained with Congo red appears pale to dull red under nonpolarized light ( Figure 5 ) but exhibits brilliant birefringence (usually "apple green") under polarized light ( Figure 6 ). Other methods for amyloid detection include fluorescent or metachromatic stains and immunohistochemistry.
recommendation:Amyloid in the adrenal should be diagnosed as present without assignment of a severity grade. Any associated loss or degeneration of cells should not be diagnosed separately but should be described in the pathology narrative. Whether the adrenal amyloid deposits are localized or part of a systemic distribution should also be addressed in the narrative. If amyloid is seen in both adrenal glands, the modifier "bilateral" should be added to the diagnosis (lesions are assumed to be unilateral unless otherwise indicated).
Brayton CF, Treuting PM, Ward JM. 2012. Pathobiology of aging mice and GEM: Background strains and experimental design. Vet Pathol 49:85-105. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/22215684
Elghetany MT, Saleem A. 1988. Methods for staining amyloid in tissues: A review. Stain Technol 63:201-212. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/2464206
Hamlin MH, Banas DA. 1990. Adrenal 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, 501-518. Abstract: https://www.ncbi.nlm.nih.gov/nlmcatalog/9002563
Howie AJ, Brewer DB, Howell D, Jones AP. 2008. Physical basis of colors seen in Congo red-stained amyloid in polarized light. Lab Invest 88:232-242. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/18166974
National Toxicology Program. 1993. NTP TR-417. Toxicology and Carcinogenesis Studies of p-Nitrophenol (CAS No. 100-02-7) in Swiss Webster Mice (Dermal Studies). NTP, Research Triangle Park, NC. Abstract: https://ntp.niehs.nih.gov/go/7714
National Toxicology Program. 2010. NTP TR-558. Toxicology and Carcinogenesis Studies of 3,3',4,4'-Tetrachloroazobenzene (TCAB) [CAS No. 14047-09-7] in Harlan Sprague-Dawley Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC. Abstract: https://ntp.niehs.nih.gov/go/33564
National Toxicology Program. 2012. NTP TR-576. Toxicology and Carcinogenesis Studies of Trimethylpropane Triacrylate (Technical Grade) (CAS No. 15625-89-5) in F344/N Rats and B6C3F1/N Mice (Dermal Studies). NTP, Research Triangle Park, NC. Abstract: https://ntp.niehs.nih.gov/go/37176
Nyska A, Maronpot RR. 1990. Adrenal gland. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 509-536. Abstract: http://www.cacheriverpress.com/books/pathmouse.htm
Rosol TJ, Yarrington JT, Latendresse J, Capen CC. 2001. Adrenal gland: Structure, function, and mechanisms of toxicity. Toxicol Pathol 29:41-48. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/11215683
Sass B. 1983. Amyloidosis, adrenal, mouse. In: Monographs on the Pathology of Laboratory Animals: Endocrine System (Jones TC, Mohr U, Hunt RD, eds). Springer, Berlin, 57-59. Abstract: http://www.springer.com/medicine/pathology/book/978-3-642-64649-2
Yarrington JT. 1996. Adrenal cortex. In: Pathobiology of the Aging Mouse, Vol 1 (Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM, eds). International Life Sciences Press, Washington, DC, 124-133.
Web page last updated on: December 30, 2014