JPC SYSTEMIC PATHOLOGY

INTEGUMENT SYSTEM

August 2016

I-F04

Signalment (JPC #1596989):  Adult female domestic shorthair cat.

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  

Slide A: Haired skin and subcutis:  Diffusely expanding the deep dermis and subcutis are multiple coalescing nodules of pyogranulomatous inflammation, composed of numerous viable and degenerate neutrophils, epithelioid macrophages, scattered multinucleated giant cells, and rare lymphocytes and plasma cells admixed with moderate numbers of reactive fibroblasts (fibrosis), eosinophilic cellular and karyorrhectic debris, fibrin, hemorrhage, and edema.  Scattered throughout the nodules are many golden-brown pigmented fungal yeast and hyphae. Yeast are ovoid, 7 to 20 um in diameter, with 2-3 um-thick dark brown cell walls, clear to pale brown cytoplasm with a central basophilic nucleus.  Hyphae are 5-10 um wide, septate with irregular, dichotomous and non-dichotomous, acute angle to right angle branching and thin, pigmented, nonparallel walls.  Multifocally there are intact and degenerate fungal elements present within the cytoplasm of macrophages and multi-nucleated giant cells.

Slide B (Periodic acid-Schiff stain):  Haired skin and subcutis:  The fungal elements are strongly PAS positive.

MORPHOLOGIC DIAGNOSIS:  Haired skin and subcutis:  Dermatitis and panniculitis, pyogranulomatous, diffuse, severe, with many dematiaceous yeast and few hyphae, domestic shorthair, feline.

ETIOLOGIC DIAGNOSIS:  Cutaneous phaeohyphomycosis

CAUSE:  Pigmented (dematiaceous) fungi

CONDITION:  Phaeohyphomycosis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS: 

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Bonar CJ, Garner MM, Weber ES, Keller CJ. Pathologic findings in weedy (Phyllopteryx taeniolatus) and leafy (Phycodurus eques) seadragons. Vet Pathol. 2013;50(3):368-376.
  2. Chandler FW, Kaplan W, Ajello L. Color Atlas and text of the Histopathology of Mycotic Diseases. Chicago IL: Year Book Medical Publishers; 1980: 76-77, 92-95.
  3. Grooters AM, Foil CS. Miscellaneous fungal infections. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St Louis MO: Elsevier Saunders; 2012: 685-688.
  4. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Infectious nodular and diffuse granulomatous and pyogranulomatous diseases of the dermis. In: Skin Diseases of the Dog and Cat, Clinical and Histopathological Diagnosis. 2nd ed. Ames, IA: Blackwell; 2005: 301-303.
  5. Hargis AM, Ginn PE. The integument. In: McGavin MD, Zachary JF, ed. Pathologic Basis of Veterinary Disease. 5th ed. Louis, MO: Elsevier Mosby; 2012: 1029-1030.
  6. Mauldin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Saunders Elsevier; 2016: 654-655.
  7. Nyaoke A, Weber ES, Innis C, Stremme D, Dowd C, Hinckley L, Gorton T, Wickes B, Sutton D, de Hoog S, Frasca Jr S. Disseminated phaeohyphomycosis in weedy seadragons (Phyllopteryx taeniolatus) and leafy seadragons (Phycodurus eques) caused by species of Exophiala, including a novel species. J Vet Diagn Invest. 2009; 21:69-79.
  8. Olias P, Hammer M, Klopfleisch R: Cerebral phaeohyphomycosis in a green iguana (Iguana iguana). J Comp Path. 2010; 143:61-64.
  9. Seyedmousavi S, Guillot J, de Hoog GS. Phaeophycomycoses, emerging opportunistic diseases in animals. Clin Microbiol Rev. 2013;26(1):19-35.
  10. Stringer EM, Garner MM, Proudgoot JS, Ramer JC, Bowman MR, Hock GH, Bradway DS. Phaeohyphomycosis of the carapace in an Aldabra tortoise (Geochelone gigantea). J Zoo Wildl Med. 2009;40:160-167.


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