October 2016

I-F05 (NP)

Signalment (JPC# 1629462):  Four-year-old, female, rhesus monkey (Macaca mulatta)

HISTORY:  Nodular lesions were present in the subcutaneous tissues near the right scapula and within the pharynx.


SLIDE A:  Haired Skin:  Expanding the dermis and subcutis, elevating the mildly acanthotic, multifocally ulcerated epidermis and extending to one surgical margin is a well-demarcated, thinly encapsulated, 1 x 3 cm nodule composed of predominantly multinucleated giant cells admixed with moderate numbers of reactive fibroblasts.  Multinucleated giant cells are primarily Langhans type, with occasional foreign-body type, and contain up to 20 nuclei.  Multifocally, multinucleated giant cells surround variably sized foci of large foamy epithelioid macrophages.  Multifocally surrounding smaller caliber subcuticular and dermal vessels there are accumulations of numerous lymphocytes, scattered plasma cells, neutrophils, and eosinophils.  Rarely within the giant cell cytoplasm, there are 2‑4 um wide, parallel, thick-walled, septate hyphae with non-dichotomous branching, and 8‑12 um diameter yeast.  Overlying the ulcerated dermis is a serocellular crust composed of necrotic debris, degenerate neutrophils, and fibrin. 

SLIDE B:  Haired skin (PAS):  Multinucleated giant cells contain variable numbers of PAS positive, 2-4 um diameter, parallel, thick-walled, septate hyphae with non-dichotomous branching and occasional bulbous swellings.  Multifocally there are irregularly round, 8-12 um diameter spheres with blue central 3-7 um cores surrounded by a clear halo (yeast).

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Dermatitis, granulomatous, nodular, focally extensive, moderate, with ulceration, and many intrahistiocytic fungal hyphae and yeast, rhesus monkey (Macaca mulatta), nonhuman primate.

ETIOLOGIC DIAGNOSIS:  Dermal paecilomycosis

CAUSE:  Paecilomyces sp.

CONDITION:  Cutaneous hyalohyphomycosis (paecilomycosis)










  1. Chandler FW, Kaplan W, Ajello L. Color Atlas and Text of the Histopathology of Mycotic Diseases. London, England: Wolfe Medical Publications Ltd. ;1980: 102-103, 272.
  2. Fleischman RW, McCracken D. Paecilomycosis in a nonhuman primate (Macaca mulatta). Vet Pathol. 1977;14:387-391.
  3. Foley JE, Norris CR, Jand SS. Paecilomycosis in dogs and horses and a review of the literature. J Vet Intern Med. 2002; 16:238-243.
  4. Grooters AM, Carol SF. Miscellaneous fungal infections. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO: Elsevier Saunders; 2012: 676-7, 684-5.
  5. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin Diseases of the Dog and Cat. 2nd ed. Oxford, UK: Blackwell; 2005: 301-303.
  6. Hargis AM, Ginn PE. The integument. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Elsevier Mosby; 2012: 1040.
  7. Mauldin EA, Peters-Kennedy J. Integumentary system. In: In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier; 2016:653.

Click the slide to view.

Click on image for diagnostic series.

Back | Home | Contact Us | Links | Help |