JPC SYSTEMIC PATHOLOGY

INTEGUMENT SYSTEM

September 2016

I-M10

 

Signalment (JPC #1902435):  1-year-old Bernese mountain dog

HISTORY: This dog presented with chronic anorexia, weight loss, stertorous respiration, conjunctivitis with prominent chemosis, and multiple cutaneous nodules over the entire body, but especially in nasal regions, eyelids, and scrotum.

HISTOPATHOLOGIC DESCRIPTION:  Haired skin, pinna:  Expanding the deep dermis both dorsal and ventral to the auricular cartilage are multifocal to coalescing perivascular nodules of predominantly of histiocytes, admixed with fewer lymphocytes, plasma cells, neutrophils and multinucleated giant cells. Inflammatory cells occasionally surround adnexae or extend into the superficial dermis.  Angiocentric nodules are separated by dense bands of fibrous connective tissue and edema.  Vessel walls are often infiltrated or obscured by similar inflammatory cells, fibrin and necrotic debris (fibrinonecrotizing vasculitis), and vascular lumina are multifocally occluded by eosinophilic fibrillar material with embedded cellular debris and inflammatory cells (fibrin thrombi).  The overlying epidermis is multifocally hyperplastic, with prominent rete ridges, and acanthosis.  Within the epidermis there is moderate orthokeratotic hyperkeratosis and scattered intracorneal foci of necrotic debris, rare degenerate neutrophils and occasional colonies of 2 um diameter cocci (intracorneal pustules).  Within the superficial dermis, there are few macrophages containing melanin (pigmentary incontinence). 

MORPHOLOGIC DIAGNOSIS:  Haired skin, pinna:  Atypical histiocytic proliferation, angiocentric, multifocal to coalescing, marked, with fibrinonecrotizing vasculitis, fibrin thrombi, fibrosis, epidermal hyperplasia, and hyperkeratosis, Bernese Mountain Dog, canine.  

CAUSE:  Unknown

CONDITION:  Systemic reactive histiocytosis

GENERAL DISCUSSION:

(1) Nonmalignant non-neoplastic (cutaneous histiocytosis, systemic histiocytosis

(2) Nonmalignant neoplastic (cutaneous histiocytoma)

(3) Malignant neoplastic (localized histiocytic sarcoma, disseminated histiocytic sarcoma, hemophagocytic histiocytic sarcoma)

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

 ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

For microscopic findings:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Affolter VK, Moore PF. Canine cutaneous and systemic histiocytosis. Am J Dermatopathol. 2000;22:40-48.
  2. Affolter VK, Moore PF. Localized and disseminated histiocytic sarcoma of dendritic cell origin in dogs. Vet Pathol. 2002;39:74-83.
  3. Affolter VK, Moore PF. Feline progressive histiocytosis. Vet Pathol. 2006;43:646-655.
  4. Croomer AR, Liptak JM. Canine histiocytic diseases. Compendium 2008;30:202-217.
  5. Gross TL, Ihrke PJ, Walder WJ, Affolter VK. Noninfectious nodular and diffuse granulomatous and pyogranulomatous diseases of the dermis. In: Skin Disease of the Dog and Cat. 2nd ed. Ames, IA: Blackwell Publishing; 2005:323-327.
  6. Mauldin EA, Peters-Kennedy J. Integumentary system. In: In: Maxie MG Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Ltd. 2016:728-730.
  7. Moore PF. A review of histiocytic diseases of dogs and cats. Vet Pathol. 2014;51:167-184.
  8. Ruple A, Morley PS. Risk factors associated with development of histiocytic sarcoma in Bernese mountain dogs. J Vet Intern Med. 2016;30: 1197–1203. Scott DW, Miller WH, Griffin CE. Muller & Kirk's Small Animal Dermatology. 6th ed. Philadelphia, Pennsylvania: WB Saunders Company;2001:1346-1357.
  9. Valli VEO, Kiupel M, Bienzle D. Histiocytic proliferative diseases. In: Maxie MG Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. Philadelphia, PA: Elsevier Ltd. 2016:247-250.


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