JPC SYSTEMIC PATHOLOGY

INTEGUMENT SYSTEM

September 2016

I-M17 (NP)

 

Signalment:  A three-year-old spayed female mixed breed dog

HISTORY:  This dog had nodular eruptions over the muzzle and around the nares. 

HISTOPATHOLOGIC DESCRIPTION:  Haired skin: Infiltrating and expanding the dermis, elevating the mildly hyperplastic epidermis, and surrounding, separating and replacing the adnexa are multifocal to coalescing, densely cellular inflammatory infiltrates that track linearly along hair follicles and form poorly defined, elongate (“cigar-shaped”) nodules up to 2 mm in length. The nodules are composed of abundant epithelioid macrophages, lymphocytes, plasma cells, fewer multi-nucleated giant cells (foreign body type) and neutrophils admixed with individual cell necrosis, few reactive fibroblasts, and small amounts of loose collagenous connective tissue (fibrosis). Multifocally, apocrine and sebaceous glands, and lymphatics are ectatic (edema) and blood vessels are lined by hypertrophied endothelium (reactive). Multifocally throughout the dermis are areas of hemorrhage and increased clear space that separates fibrous connective tissue (edema). The multifocally mildly hyperplastic epidermis is characterized by hyperplasia of the stratum spinosum (acanthosis) and multifocal epidermal hyperpigmentation, and mild orthokeratotic hyperkeratosis.

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Dermatitis, periadnexal and nodular, granulomatous, multifocal to coalescing, moderate, with mild edema, acanthosis, and orthokeratotic hyperkeratosis, mixed breed, canine.

ETIOLOGIC DIAGNOSIS:  Idiopathic granulomatous dermatitis

CONDITION:  Sterile granuloma/pyogranuloma syndrome (SPGS)

SYNONYM:  Periadnexal multinodular granulomatous dermatitis (PMNGD)/ Pyogranuloma syndrome; Idiopathic sterile granuloma/pyogranuloma

GENERAL DISCUSSION: 

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

 

ADDITIONAL DIAGNOSTIC TESTS:  

DIFFERENTIAL DIAGNOSIS:

Gross:

Microscopic:

COMPARATIVE PATHOLOGY: 

REFERENCES: 

  1. Carpenter JL, Thornton GW, Moore FM, King NW Jr. Idiopathic periadnexal multinodular granulomatous dermatitis in twenty-two dogs.  Vet Pathol.  1987 Jan;24(1):5-10.
  2. Cornegliani L, Fondevila D, Vercelli A, Mantero G, Fondati A. PCR technique detection of Leishmania but not Mycobacterium spp. in canine cutaneous ‘sterile’ pyogranuloma/granuloma syndrome. Vet Dermatol. 2005;16(4):233-238.
  3. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis. 2nd ed. Oxford, UK: Blackwell Publishing Co.; 2005: 410-415.
  4. Mauldin EA, Peters-Kennedy J. Integumentary system.  In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier; 2015:699-702.   
  5. Santoro D, Prisco M, Ciaramella P. Cutaneous sterile granulomas/pyogranulomas, leishmaniasis and mycobacterial infections.  J Small Anim Pract.  2008;49(11):552-61.
  6. Scott DW, Miller WH, Griffin CE. In: Muller & Kirk’s Small Animal Dermatology. 6th ed. Philadelphia, PA: WB Saunders Company; 2013:1136-1140.


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