JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
September 2018
D-N06

Signalment(JPC #2300082):  13-year-old female shepherd mix dog

HISTORY:  None

HISTOPATHOLOGIC DIAGNOSIS:  Anal sac:  Infiltrating the connective tissue underlying the anal sac epithelium, and effacing and replacing adjacent anal sac glands and skeletal muscle, is an unencapsulated, multilobulated, densely cellular neoplasm composed of polygonal cells arranged in cords, tubules, acini,  and solidly cellular areas separated and supported by a fine fibrovascular stroma.  Multifocally, neoplastic cells palisade around a central  lumen, which is either clear or filled with eosinophilic material, forming rosette-like structures.  Neoplastic cells are polygonal to columnar with variably distinct cell borders and a moderate amount of eosinophilic granular cytoplasm.  Nuclei are often basilar and round to oval with coarsely stippled chromatin, and up to two nucleoli.  There is mild anisokaryosis.  Mitoses average 2 per HPF with occasional bizarre mitoses.  Multifocally at the periphery of the neoplasm, there are clusters of neoplastic cells within lymphatics and blood vessels.  There is rare scattered single cell necrosis, occasional eosinophilic amorphous material (secretory product) in tubuloacinar lumina, multifocal mild hemorrhage and scattered lymphocytes, plasma cells, and hemosiderin-laden macrophages which occasionally surround clear acicular cholesterol clefts within the connective tissue stroma.  Multifocally, similar inflammatory cells infiltrate the subepithelial connective tissue of the anal sac, and remaining apocrine glands are moderately ectatic with attenuated epithelium.

MORPHOLOGIC DIAGNOSIS:  Anal sac:  Anal sac gland adenocarcinoma (adenocarcinoma of the apocrine glands of the anal sac), shepherd mix, canine.

GENERAL DISCUSSION:

PATHOGENESIS (for hypercalcemia):

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

DIFFERENTIAL DIAGNOSIS:

Hypercalcemia

Hyperparathyroidism (primary: idiopathic or functional parathyroid neoplasms)

Addisons & Acidosis

Renal Disease (horses, rarely in young dogs)

Vitamin D toxicosis: Hypervitaminosis D, Calciferol rodenticides, Vit D glycoside plants (Solanum malacoxylon, Cestrum diurnum, Trisetum flavescens)

Immobilization

Osteolytic lesions

Neoplasia (5: apocrine gland adenocarcinoma of anal sac, lymphoma, multiple myeloma, metastatic bone tumors, SCC in horse)

Spurious (granulomatous dz, hyperproteinemia, hemoconcentration, thiazide diuretics)

COMPARATIVE PATHOLOGY:

References:

  1. Goldschmidt MH, Goldschmidt KH. Epithelial and Melanocytic Tumors of the Skin. In: Meuten J, ed. Tumors in Domestic Animals. 5th ed. Ames, Iowa: Iowa State Press; 2017:120-122.
  2. Latimer KS. Duncan and Prasse’s Veterinary Laboratory Medicine: Clinical pathology. 5th ed. Ames, Iowa: Iowa State University Press; 2011:299-304.
  3. Mauldin EA, Peters-Kennedy J. Integumentary System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St Louis, MO: Elsevier; 2016: 720.
  4. Miller MA. Endocrine System. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:719.
  5. Ogawa B, Taniai E, Hayashi H, et al. Neuroendocrine carcinoma of the apocrine glands of the anal sac in a dog. J Vet Diagn Invest. 2011;23(4):852.
  6. Pontana CP, Padgett S, Gamblin RM. Surgical excision of anal sac apocrine gland adenocarcinomas with and without adjuctive chemotherapy in dogs: 42 cases (2005-2011). J Am Vet Med Asso. 2015 Apr 15;246(8):877-84.
  7. Rosol TJ, Grone A. Endocrine Glands. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St Louis, MO: Elsevier; 2016: 274, 307-308.
  8. Rosol TJ, Meuton DJ. In: Meuten J, ed. Tumors in Domestic Animals. 5th ed. Ames, Iowa: Iowa State Press; 2017:816-820.
  9. Suzuki K, Morita R, Hojo Y et al. Immunohistochemical characterization of neuroendocrine differentiation of canine anal sac glandular tumors. J Comp Path. 2013;149(2-3):199.


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