September 2013

I-F08 (NP)

Signalment (JPC #1665005):  Monkey


HISTOPATHOLOGIC DESCRIPTION:  Slide A:  Mucous membrane (site not specified):  Markedly expanding the subepithelial connective tissue are multifocal to coalescing nodular cellular infiltrates predominately composed of macrophages admixed with moderate numbers of non-degenerate and degenerate neutrophils, and fewer eosinophils, lymphocytes, plasma cells, and multinucleated giant cells (Langhans and foreign-body type) and variable amounts of eosinophilic cellular and karyorrhectic debris (necrosis), fibrin, and hemorrhage.  Occasionally these aggregates have central areas of necrosis bordered by macrophages and few neutrophils, further surrounded by collagen and reactive fibroblasts (granulomas).  Scattered throughout the inflammation and within multinucleated giant cells are numerous 4-8um diameter round yeast with 1um thin eosinophilic walls and clear centers that are surrounded by clear space that is up to 10um thick (capsule).  Scattered similar inflammatory cells extend multifocally into the adjacent skeletal muscle, disrupting and separating myofibers.  The superficial subepithelial connective tissue is expanded by fibrin, edema, few plasma cells, lymphocytes, and rare neutrophils.

Slide B:  Mucicarmine stain:  The capsule is 3-8um thick and bright red (carminophilic).  Yeast are 4-8um in diameter, occasionally clustered, and frequently bud with a narrow base.  The organisms are surrounded by a 10-15um thick, clear space (shrinkage artifact) with short radiating carminophilic spines extending from the capsule.

MORPHOLOGIC DIAGNOSIS:  Mucous membrane (site not specified):  Cellulitis, pyogranulomatous, multifocal to coalescing, marked, with numerous encapsulated yeast, etiology consistent with Cryptococcus spp., species not specified, non-human primate.

ETIOLOGIC DIAGNOSIS:  Mucosal cryptococcosis

CAUSE:  Cryptococcus neoformans

SYNONYM:  European blastomycosis



    • Polysaccharide capsule prevents phagocytosis by macrophages, inhibits leukocyte migration, and inhibits recruitment of inflammatory cells
    • Organism produces laccase which catalyzes the formation of a melanin-like pigment which has antioxidant properties
    • Urease expression by organism appears to promote sequestration in microcapillaries, a critical step in dissemination to the brain


TYPICAL GROSS FINDINGS: (lesions in the skin)





For microscopic findings:



  1. Bildfell RJ, Long P, Sonn R. Cryptococcosis in a llama (Lama glama). J Vet Diagn Invest. 2002: 14:337-339.
  2. Craig LE, Dittmer KE, Thompson, KG. Bones and Joints.  In: Maxie MG Jubb, Kennedy,and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Ltd. 2016:104.
  3. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. In: Skin diseases of the dog and cat. 2nd ed. St Louis, MO: Blackwell publishing; 2005:291.
  4. Magalhães GM, Saut JP, Beninati T, Medeiros AA, Queiroz GR, Tsuruta SA, Krockenberger M, Headley SA. Cerebral cryptococcomas in a cow.  J Comp Pathol. 2012;147(2-3):106-10.
  5. Sykes JE, Malik R. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO: Elsevier Saunders; 2012:621-634
  6. Hargis AM, Ginn PE. The integument. In: Zachary JF, McGavin MD, eds. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Elsevier Mosby; 2012:970.
  7. Paulin J, Morshed M, Armién AG. Otitis interna induced by Cryptococcus neoformans var. grubii in a cat. Vet Pathol. 2013; 50(2):260-3.
  8. Scott DW, Miller, Jr. WH, Griffin CE. In: Muller and Kirk’s Small Animal Dermatology, 395-400. Philadelphia, Pennsylvania: WB Saunders Co; 2001:395-400.

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