JPC SYSTEMIC PATHOLOGY
ENDOCRINE SYSTEM
January 2019
E-M01

Signalment (JPC #1939231):  BB/Wistar rat

HISTORY:  None

MICROSCOPIC DIAGNOSIS (Slide a):  Pancreas:  There is a diffuse decrease in number of the islets of Langerhans.  The few remaining islets are infiltrated by moderate numbers of lymphocytes, plasma cells and fewer histiocytes, which occasionally extend into the surrounding pancreatic acini.  Multifocally the periductal connective tissue is moderately expanded by a similar inflammatory infiltrate. 

MORPHOLOGIC DIAGNOSIS:  Pancreas, islets of Langerhans:  Atrophy, diffuse, moderate, with lymphocytic insulitis, BB/Wistar rat, rodent.

ETIOLOGIC DIAGNOSIS:  Immune-mediated insulitis and atrophy

MICROSCOPIC DIAGNOSIS (Slide b):  Thyroid gland:  There is diffuse disruption of thyroid architecture by numerous lymphocytes, plasma cells and fewer histiocytes that separate, surround, and replace thyroid follicles.  The remaining follicles are either small, irregular or collapsed, and contain little colloid or are enlarged up to 200 um in diameter and contain eosinophilic cellular and karyorrhectic debris (necrosis), sloughed epithelial cells, few macrophages and neutrophils admixed with variable amounts of colloid.  Multifocally, the adjacent fibroadipose tissue is expanded by few lymphocytes and neutrophils and a mild amount of clear space separates the connective tissue (edema).

MORPHOLOGIC DIAGNOSIS:  Thyroid gland:  Thyroiditis, lymphoplasmacytic, diffuse, severe, with mild periglandular steatitis, BB/Wistar rat, rodent.

ETIOLOGIC DIAGNOSIS:  Immune-mediated thyroiditis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:  No gross lesions

TYPICAL LIGHT MICROSCOPIC FINDINGS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Awata T, Guberski D, Like A. Genetics of the BB rat: Association of autoimmune disorders (diabetes, insulitis, and thyroiditis) with lymphopenia and major histocompatibility complex class II. Endocrinology 1995;136:5731-5734.
  2. Doukas J, Mordes J, Swymer C, Niedzwiecki D, Mason R, Rozing J, Rossini A, Greiner D. Thymic epithelial defects and predisposition to autoimmune disease in BB rats. Amer J Pathol 1994;145:1517-1524.
  3. Fehsel K, Kolb-Bachofen V, Kroncke K-D. Necrosis is the predominant type of islet cell death during development of insulin-dependent diabetes mellitus in BB rats. Lab Invest 2003;83:549-559.
  4. Ferguson DC and Hoenig M. Endocrine system.  In Latimer KS, ed. Duncan and Prasse’s Veterinary Laboratory Medicine.  5th ed. Ames, IA: Iowa State University press; 2011: 304-313.
  5. Hessner MJ, Wang X, Meyer L, Geoffrey R, Jia S, Fuller J, Lernmark A, Ghosh S. Involvement of eotaxin, eosinophils, and pancreatic predisposition in development of type I diabetes mellitus in the BioBreeding rat. J Immunol 2004;173:6993-7002.
  6. Jennings V, Dillehay D. Immunology. In: Suckow MA, Weisbroth SH, Franklin CL, eds. The Laboratory Rat.  London, UK: Elsevier Academic Press; 2006:853-854.
  7. Jubb KA, Stent AW. Pancreas. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier; 2016:368-373.
  8. Miller MA. Endocrine system. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:701, 718.
  9. Rosol TJ, Grone A. Endocrine glands. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. Philadelphia, PA: Elsevier; 2016:310-320.


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