Signalment:  

6-month-old, spayed female, Siamese cross cat, Felus catus or domesticusChronic vomiting and weight loss. Exploratory laparotomy revealed an abnormal ileocecal region that was resected and submitted for histologic examination. The cat did poorly following the exploratory laparotomy and was euthanized. Although the owner declined a complete postmortem examination, they consented to collection and submission of some tissues for identifying the fungal agent.

Gross Description:  

A 5.1 x 5.0 cm section of cecum with attached short segments of ileum and colon was submitted

Histopathologic Description:

At the diverticulum of the cecum there was a focally extensive area of severe necrosis with coalescing bands and large aggegrates of inflammatory cells (neutrophils, histiocytes [includes epithelioid and vacuolated forms], small lymphocytes and plasma cells) admixed with irregular streams of spindled cells with a plump nucleus. Multiple aggregates of nonpigmented, branching, pseudohyphae and septate hyphae (4 to 8 um thick) were present within the inflammatory infiltrate and on the mucosal surface (Fig. 3-1). Sections from the ileum and colon were unremarkable.

Morphologic Diagnosis:  

Severe, focally extensive, necrotizing, pyogranulomatous typhlitis due to Candida albicans

Lab Results:  

Fresh liver, small intestine, and a swab from the colon were submitted for definitive fungal identification. Candida albicans was cultured from all three sites.

Condition:  

Candida albicans

Contributor Comment:  

Members of the genus Candida are saprophytic, dimorphic fungi in the family Cryptococcaceae.(3) In the yeast phase, Candida species normally inhabit the alimentary, upper respiratory and genital mucosae of mammals.(3,1) Candida species are first acquired by neonates as they pass through the birth canal, colonize the oral, gastrointestinal, upper respiratory and genital mucosae for the life of the animals.(3) Their presence normally evokes no reaction. Under certain circumstances, Candida species can invade deeper host tissues and proliferate as blastoconidia, pseudohyphae and branched, septate hyphae.(3) In other instances, they can disseminate via the bloodstream to many tissues. (3)

Pathogenic factors of Candida species are important in determining their relative virulence in the host.(3) Candida albicans can invade the columnar epithelium of the intestines.(3) The yeast form of C. albicans colonizes epithelia, while hyphae are the more invasive form and are found within deeper tissue invasion.(3)

Local proliferation of Candida species on mucosal surfaces is the first step in the spread of infection. Overgrowth of Candida species within the gastrointestinal tract is inhibited by mucosal microflora.(1) Factors that upset the balance of normal endogenous microflora may cause Candida organisms to proliferate. Intestinal candidiasis may be sequelae to parvoviral infections or alterations in microflora caused by systemic antibiotic therapy.(3,1,5) Mycotic ileitis and colitis in cats have been reported as a secondary complication of infection with feline panleukopenia virus.(5,7) Localized candidiasis has been reported to occur in chronically immunosuppressed cats and in those with nonhealing ulcers of the gastrointestinal tract.(3) However, in one study retroviral status (feline leukemia virus, FeLV and feline immunodeficiency virus, FIV) did not influence the ability to isolate C. albicans from feline cutaneous and mucosal samples.(6) The FeLV and FIV status of this patient was not established and routine bloodwork, that may have demonstrated panleukopenia, was not performed.

Histologic examination of lesions reveals multifocal abscesses or areas of necrosis that contain abundant blastoconidia, pseudohyphae and true hyphae surrounded by mixed inflammatory cells.(3) Infiltrates tend to be minimal in profoundly immunosuppressed or leukopenic animals.(3) The proprial infiltrate in the cecum from this cat would suggest it was not immunosuppressed or leukopenic.

Candida species grow well on blood agar and are often isolated from specimens submitted for bacterial culture. Organisms may sometimes be cultured from many tissues at surgery or necropsy, but such results should be interpreted cautiously.(3) Culture of Candida species from cutaneous, mucosal or exudates alone are not an indicator of infection.(3) Histologic confirmation of invasion and host reaction are essential.(3) Mucosal and cutaneous biopsies should be submitted for histologic and culture examination simultaneously. A definitive histologic diagnosis can sometimes be made in the presence of negative culture results.

JPC Diagnosis:  

1. Cecum (per contributor): Typhlitis, necrotizing and pyogranulomatous, diffuse, severe, with vasculitis, fibrin, hemorrhage, edema, intralesional hyphae and pseudohyphae, and rare eosinophilic intranuclear inclusion bodies.
2. Lymph node: Lymphoid depletion, diffuse, severe, with draining hemorrhage, edema, and rare eosinophilic intranuclear inclusion bodies.

Conference Comment:  

The contributor provides an excellent review of Candida sp. In addition, several eosinophilic intranuclear inclusion bodies were observed within lymphocytes in the lymph nodein the intestinal epithelium. Immunosuppression is suspected to have predisposed this 6-month-old cat to concurren viral and Candida infections. The inclusion bodies, along with the necrotizing lesion and lymphoid depletion, are suggestive of feline parvovirus (PV) infection. Inclusion bodies are generally found only early in infection.(2) Intestinal lesions of PV are similar to those seen with feline leukemia virus associated enteritis (FAE), feline enteric coronavirus (CoV), and enteritis of unknown etiology (EUE). Crypt necrosis is the primary lesion observed with PV, FAE and EUE, while necrosis of the villar tip is the primary lesion with CoV. The inflammation is marked in FAE, EUE and CoV, unlike in PV. Many macrophages are present in EUE. The inflammation is composed primarily of T lymphocytes in PV and FAE. There is lymphoid depletion with PV and EUE. Lymphoid tissue is normal to hyperplastic with FAE. There is decreased bone marrow activity in PV. Bone marrow activity is slightly increased with FAE, CoV and EUE.(4) Intrauterine infection results in congenital cerebellar hypoplasia in kittens.(2)

	PV	FAE	CoV	EUE
Necrosis	crypts	crypts (less severe)	villar	crypts
Inflammation	↑ (T cells)	↑ ↑ (T cells)	↑ ↑ (lymphocytes)	↑ ↑ (macrophages)
Lymphoid tissue	depleted	Normal to hyperplastic		depleted
Bone marrow	↓	Slight ↑	Slight ↑	Slight ↑

References:

1. Brown CC, Baker DC, Barker IK: Alimentary system. In: Pathology of Domestic Animals, ed. Maxie MG, 5th ed., vol. 2, p. 230. Saunders Elsevier, London, UK, 2007
2. Gelberg HB: Alimentary system. In: Pathological Basis of Veterinary Disease, eds. McGavin MD, Zachary JF, 4th ed., pp. 378-380. Mosby, St. Louis, MO, 2007
3. Greene CE and Chandler FW. Candidiasis and Rhodotorulosis. In: Infectious Diseases of the Dog and Cat, ed. Greene CE, 3rd ed., pp. 627- 632. Saunders Elsevier, London, UK, 2006
4. Kipar A, Kremendahl J, Jackson ML, Reinacher M: Comparative examination of cats with feline leukemia virus-associated enteritis and other relevant forms of enteritis. Vet Pathol 38:359-371, 2001
5. Lorenzini R and De Bernardis F: Antemortem diagnosis of an apparent case of feline candidiasis. Mycopathologia 93:13-14, 1986
6. Ochiai K, Valentine B and Altschul M: Intestinal candidiasis in a dog. Vet Rec 146:228-229, 2000
7. Sierra P, Guillot J, Jacob H, Bussieras S, Chermette R: Fungal flora on cutaneous and mucosa surfaces of cats infected with feline immunodeficiency virus or feline leukemia virus. American Journal of Veterinary Research 61:158-161, 2000

Click the slide to view.

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3-1. Cecum, cat.

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