JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

SEPTEMBER 2016

I-M06

 

Signalment (JPC # 21474-29):  Dog, breed not specified.

HISTORY:  This dog had bilaterally symmetrical, rugose thickening, lichenification, and gray-black hyperpigmentation of the axillary skin.

HISTOPATHOLOGIC DESCRIPTION:  Haired skin, axilla (per contributor):  Diffusely, the epidermis is moderately to markedly hyperplastic with prominent rete ridges, thickening of the stratum spinosum (acanthosis), intercellular edema (spongiosis) and moderate parakeratotic hyperkeratosis.  Multifocally there are increased intracytoplasmic melanin granules within the stratum spinosum, stratum granulosum, and stratum corneum (hyperpigmentation).  Within the superficial dermis, there are numerous melanomacrophages and free melanin granules (pigmentary incontinence) as well as infiltration by low numbers of neutrophils, lymphocytes, plasma cells, and macrophages.  Apocrine glands are ectatic, frequently contain amphophlic secretory product and are lined by hyperplastic epithelial cells with abundant microvacuolated cytoplasm.

MORPHOLOGIC DIAGNOSIS:  Haired skin, axilla (per contributor):  Hyperplasia, epidermal, diffuse, marked, with hyperkeratosis, hyperpigmentation, and pigmentary incontinence, breed unspecified, canine.

CONDITION:  Acanthosis nigricans

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Hyperplastic diseases of the epidermis. In:  Skin Diseases of the Dog and Cat. 2nd ed. Ames, IA: Blackwell Publishing Company; 2005: 151-152.
  2. Hargis AM, Ginn PE. The integument. In: Zachery JF, McGavin MD. Pathologic Basis of Veterinary Disease. Vol 1. 5th ed. Philadelphia, PA: Elsevier Saunders Company; 2012:1071-1072.
  3. Lazar AJF, Murphy GF. The skin. In: Kumar V, Abbas AK, Aster JC. eds. Robbins and Cotran Pathologic Basis of Disease. 9th ed., Philadelphia, PA: Elsevier Saunders Company; 2015:1151.
  4. Mauldin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG ed. Jubb, Kennedy and Palmer’s: Pathology of Domestic Animals. Vol1. 6th ed. Philadelphia, PA: Saunders-Elsevier; 2015: 555.
  5. Miller WH, Griffin CE, Campbell KL. Congenital and hereditary defects. In: Muller and Kirk’s Small Animal Dermatology. 7th ed. WB Saunders Company, Philadelphia, PA: WB Saunders Company, 2013: 600-601.


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