JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

September 2016

I-M34

 

Signalment (JPC #2812885-01):  Military working dog

HISTORY:  None provided

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Multifocally expanding the dermis there are densely cellular areas of inflammatory cells centered on ruptured hair follicles and free hair shafts (furunculosis).  Inflammatory nodules are composed of viable and degenerate neutrophils, lymphocytes, plasma cells, and macrophages.  Adjacent, less affected hair follicles are markedly elongated, ectatic and distorted (follicular dysplasia), lined by hyperplastic epithelium, and filled with lamellated keratin debris and fragmented hair shafts admixed with degenerate neutrophilis and basophilic colonies of 1um cocci (luminal folliculitis).  Adjacent apocrine gland ducts are multifocally ectatic, filled with an eosinophilic homogenous material (inspissated secretory product) and surrounded by aggregates of lymphocytes and plasma cells (perihidradenitis).  Throughout the superficial and deep dermis dysplastic hair follicles and ectatic apocrine glands are embedded in abundant collagen (fibrosis) composed of dense bands that widely separate adnexa and which often orient perpendicular to the epidermis (vertical streaking).  Within the superficial dermis, there are scattered melanomacrophages and free melanin granules (pigmentary incontinence).  Diffusely, the overlying epidermis is moderately hyperplastic with acanthosis, prominent anastomosing rete ridges and compact orthokeratotic hyperkeratosis.  Multifocally, there is deposition of melanin granules in all layers of the epidermis (hyperpigmentation). 

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Furunculosis, pyogranulomatous, multifocal, marked, with apocrine perihidradenitis, dermal fibrosis and vertical streaking, epidermal and follicular hyperplasia, and orthokeratosis, breed unspecified, canine.

CONDITION:  Acral lick dermatitis

SYNONYMS:  Acral lick granuloma, acral pruritic nodule, neurodermatitis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Denerolle P, White SD, Taylor TS, et. al. Organic diseases mimicking acral lick dermatitis in six dogs. J Am Anim Hosp Assoc. 2007;43(4):215-220.
  2. Mauldin EA, Peters-Kennedy J, et. al. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:561-562.
  3. Gross TL, Ihrke PJ, Walder EJ, et. al. Hyperplastic diseases of the epidermis. In: Gross TL, Ihrke PJ, Walder EJ, et. al., eds. Skin Diseases of the Dog and Cat. 2nd ed. Ames, IA: Blackwell Science Ltd; 2005:140-142, 429.
  4. Hargis AM, Ginn, PE. The integument. In: Zachary JF, McGavin MD, eds. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Elsevier Mosby; 2012:1018-1019.
  5. Campbell KL, Griffin CE, Miller WH, eds. Small Animal Dermatology. 7th ed. Philadelphia, PA: WB Saunders Company; 2013:650-658.
  6. Shumaker AK, Angus JC, Coyner KS, et. al. Microbiological and histopathological features of canine acral lick dermatitis. Vet Dermatol. 2008;19(5):288-298.


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