Draining skin lesion from a desert poodle

A 16-month-old intact female Poodle in Arizona had a history of intermittent coughing of a few weeks duration. Coccidiomycosis antibody screening test results were negative for immunoglobulin (Ig) M, but were positive (1:64) for IgG. Fine needle aspiration specimens of a draining lesion on the right palmar front foot contained large numbers of neutrophils, many of which contained bacteria, and lower numbers of macrophages. A few small structures also were observed, 2-5 microm in diameter with thin, nonstaining capsules and small, round to oval densely aggregated, eccentric nuclei. Cytologic findings were consistent with septic pyogranulomatous inflammation with Coccidiodes immitis endospores. Fungal culture of a sample from the draining lesion yielded white growth with barrel-shaped arthroconidia. Identification of the organism as C immitis was confirmed by a commercial DNA probe test. Although coccidioidomycosis often is diagnosed by microscopic identification of C immitis spherules in cytologic specimens, in this case only endospores, which are released from mature spherules, were observed. In cases of suspected coccidiodomycosis, the unique morphology of endospores may be useful in making a cytologic diagnosis.     

Intracellular success: cytologic findings in an ulcerated submandibular mass from a cat

A 1-year-old neutered male domestic shorthair cat had an ulcerated, proliferative lesion in the submandibular area that did not respond to antibiotic therapy. Impression smears from the mass revealed septic pyogranulomatous inflammation, with large numbers of pleomorphic bacteria observed intracellularly within macrophages as well as neutrophils. Bacterial culture was consistent with a diagnosis of Rhodococcus equi, a facultative intracellular coccobacillus capable of replicating within macrophages. The cat's lesion resolved after treatment with rifampin and clarithromycin. R equi should be considered as a differential diagnosis when coccobacilli are recognized within macrophages in cytologic samples.     

Cytology and histopathology of canine leproid granuloma syndrome

OBJECTIVE: To describe the histopathology of canine leproid granuloma syndrome. DESIGN: Histological examination of biopsy specimens taken from dogs with leproid granuloma syndrome. Biopsies were acquired from four veterinary pathology practices after initial examination showed acid-fast bacilli or lesions suggestive of a mycobacterial aetiology. Tissue from 30 cases formed part of a retrospective survey while a further 7 cases were obtained prospectively. PROCEDURE: Tissue samples were fixed in formalin and paraffin embedded. Sections were stained with haematoxylin and eosin and Ziehl-Neelsen stains. Slides were evaluated for the type of inflammatory response and the number of bacteria. In a few cases smears made from crush preparations and needle aspirates were stained with DiffQuik and acid-fast stains. RESULTS: The common cytological feature seen in DiffQuik stained smears was numerous, often spindle-shaped, macrophages with variable numbers of lymphocytes and plasma cells and lower numbers of neutrophils. Usually few to moderate numbers of medium length bacilli were detected within macrophages or extracellularly. Histologically, lesions were chiefly pyogranulomatous within the subcutis and dermis. Pyogranulomas were composed chiefly of epithelioid macrophages and neutrophils but plasma cells and small lymphocytes were scattered throughout the lesions in which giant cells were seen. Lesions were pyogranulomatous in 36 cases and granulomatous with small suppurative foci in one. The numbers of acid-fast bacilli present were very low to low in 22 cases, moderate in 6 and regionally numerous to numerous in 9. Bacteria were pleomorphic, ranging from long, slender filaments in parallel sheaves to short and variably-beaded bacilli or highly beaded to coccoid organisms. The morphology was more uniform in DiffQuik stained smears than in fixed tissue sections. CONCLUSION: The pathology of canine leproid granuloma syndrome is highly uniform and is suggestive of saprophytic mycobacterial involvement. The morphological diversity of acid-fast bacilli probably results from differences in staining characteristics rather than indicating different species of Mycobacterium. While approximately half of the cases had only few organisms present, the veterinary practitioner using a Romanovsky stain such as DiffQuik on aspirated material might expect to obtain a rapid diagnosis in many cases. This would allow differentiation of the syndrome from neoplastic and other diseases of the skin and direct appropriate treatment at the initial presentation.     

Disseminated sporotrichosis in a cat.

Sporothrix (Sporotrichum) schenckii was identified as the causative agent of a large pyogranulomatous lesion on the right forepaw of a cat. Organisms also were observed in axillary lymph nodes of the affected forelimb and in the lungs and liver of the cat. The agent was transmitted to another domestic cat and to mice.     

Diagnosis of sporotrichosis in a donkey using direct fluorescein-labeled antibody testing.

A 4-year-old female donkey residing in an open field in Indiana was admitted for evaluation of facial lesions of 2 years duration. Cytologic and histologic examination of exudate and tissue from the lesions revealed a pyogranulomatous inflammatory reaction with numerous yeasts. Sporothrix schenckii was suspected to be the infectious agent; however, multiple culture attempts did not provide positive identification of the organism. Serologic examination supported infection with S. schenckii. A specific direct immunofluorescent antibody test performed on paraffin-embedded tissue sections confirmed the organism as S. schenckii. Clinical signs resolved after appropriate iodide therapy.     

Sporotrichosis in a nine-banded armadillo (Dasypus novemcinctus).

An adult female nine-banded armadillo (Dasypus novemcinctus) died in the quarantine station of a private Swiss zoo. Multifocal ulcerative skin lesions and multiple hemorrhages in the lungs were found at necropsy. The spleen was enlarged and dark red. Histologically, there was diffuse granulomatous infiltration, including multinucleated giant cells, of the skin lesions, lungs, spleen, liver, heart, and kidneys. Abundant periodic acid-Schiff-positive yeastlike cells were demonstrated intracellularly in giant cells and extracellularly scattered throughout the tissues. Morphology of the cells varied, with some nonbudding cells resembling Cryptococcus neoformans and others resembling Sporothrix schenckii. A diagnosis of sporotrichosis was confirmed by immunofluorescence studies. This is the first report of sporotrichosis in an armadillo in a zoological garden and the third report of sporotrichosis in D. novemcinctus.     

Disseminated blastomycosis in two California sea lions (Zalophus californianus).

Two captive California sea lions (Zalophus californianus) from different facilities were diagnosed with disseminated blastomycosis. The first, a 12-yr-old male, died after a 3-wk history of progressive anorexia and lethargy. Gross examination revealed acute jejunitis with focal perforation and associated peritonitis, along with severe purulent bronchopneumonia. The second, a 15-yr-old female, was euthanized after a 2-wk history of severe cutaneous ulceration and declining clinical condition. Gross examination revealed severe pyogranulomatous bronchopneumonia and ulcerative dermatitis. Histopathologic examination in both individuals revealed severe multifocal subacute to chronic pyogranulomatous pneumonia associated with massive numbers of fungal organisms morphologically compatible with Blastomyces sp. Fungal organisms were 8-20-microm-diameter broad-based budding yeasts with thick, refractile, double-contoured walls. The male sea lion had multifocal transmural Blastomyces-induced enteritis with subsequent rupture and peritonitis. The organism was also present in the liver, with minimal associated inflammation. The female had severe multifocal pyogranulomatous ulcerative dermatitis associated with large numbers of intralesional fungal organisms. Dissemination to the spleen had occurred in both animals. A serologic immunodiffusion test for Blastomyces dermatitidis was positive in the male. The presumptive primary pathogen in both cases was Blastomyces dermatitidis.     

Cutaneous neosporosis in two adult dogs on chronic immunosuppressive therapy.

Antemortem diagnosis of generalized ulcerative and pyogranulomatous dermatitis with numerous intralesional tachyzoites was made from skin biopsy specimens from 2 adult dogs on chronic immunosuppressive therapy. A 9-year-old Italian Greyhound was on long-term corticosteroid therapy for the treatment of a lupus-like systemic autoimmune disorder, and a 7-year-old Labrador Retriever had received several months of chemotherapy for lymphosarcoma. The tachyzoites were identified as Neospora caninum by immunoperoxidase immunohistochemistry. Both dogs were treated with clindamycin. Lesions in the Greyhound resolved; however, the Labrador Retriever was euthanized because of evidence of neuromuscular disease, despite improvement of the skin lesions. These 2 cases indicate that cutaneous neosporosis can occur in adult dogs on chronic immunosuppressive therapy. The disease may result from reactivation of a congenital infection and/or a recently acquired primary infection.     

"Carry-on" dermal baggage: a nodule from a dog. Pyogranulomatous inflammation with intralesional fungal agents

A 2-year-old intact female Australian Cattle Dog presented with a 1-cm diameter nonexudative dermal nodule on the medial aspect of the right thigh. Fine-needle aspiration revealed pyogranulomatous inflammation and many ovoid, 2-4 microm diameter, thin-capsulated, basophilic bodies that appeared to be fungal spores or yeast. Results of CBC, serum chemistry panel, lymph node palpation, and radiographs were unremarkable. Excisional biopsy and histopathology revealed pyogranulomatous folliculitis, furunculosis, and perifolliculitis. Rare fungal hyphae and spore forms were intimately associated with, and occasionally within, hair shafts. A morphologic diagnosis of dermatophytosis was made and Microsporum canis infection was confirmed by fungal culture. M canis is a common infectious agent found within the follicles and superficial keratin layers of canine skin. The kerion-type clinical presentation observed in the dog of this case is uncommonly observed with M canis. Additionally, the cytologic finding of multiple arthroconidia without hyphae is unusual. In the absence of hyphae, M canis arthroconidia may be confused with other fungal yeast bodies; therefore close scrutiny of a cytologic sample for arthroconidia associated with keratin, hair fragments, or hyphal structures is recommended.     

Lymph node aspirate from a California wine-country dog

A 4-year-old, male Golden Retriever was presented to the Veterinary Medical Teaching Hospital at the University of California-Davis with a history of lethargy, inappetance, and vomiting. The patient had generalized lymphadenomegaly, marked thrombocytopenia, mild anemia, and moderate hypoalbuminemia. Moderate to marked histiocytic inflammation and lymphocytic-plasmacytic reactivity of the mesenteric, left popliteal, and right mandibular lymph nodes were diagnosed cytologically. Many macrophages contained granular to amorphous material of a uniform blue color, occasionally in morula formation, suggestive of rickettsial organisms. Exposure to raw trout was subsequently documented, leading to a presumptive diagnosis of salmon poisoning disease (SPD). The patient responded quickly to doxycycline therapy for the causative agent of SPD (Neorickettsia helminthoeca). SPD should be considered as a differential diagnosis for a canine patient with clinical signs of vomiting, diarrhea, lethargy, and lymphadenomegaly; laboratory findings of thrombocytopenia and hypoalbuminemia; and potential exposure to raw fish from an endemic area. The cytologic finding of rickettsial inclusions within lymph node macrophages is reportedly seen within a majority of SPD cases and can be valuable in supporting a clinical suspicion of SPD, as it was in this case.     

A "down under" lesion on the muzzle of a dog

A 10-year-old, castrated, male Labrador Retriever was presented to a local veterinary practice for investigation of a firm, deeply pigmented, alopecic, subcutaneous mass (8 mm in diameter) on the left side of the muzzle. A fine-needle aspirate of the mass was submitted for cytologic evaluation to the University of Florida. Microscopically, the preparation contained a predominant population of histiocytes that contained variable numbers of intracytoplasmic, negative-staining, filamentous structures consistent with Mycobacterium sp. A presumptive diagnosis of canine leproid granuloma syndrome was based on the cytologic findings and location of the lesion. Acid-fast staining revealed bright pink, acid-fast organisms within the histiocytic cells, supporting the diagnosis. The bacteria were not detected in histopathologic sections or by a polymerase chain reaction (PCR) test 1 week later, however, possibly because of spontaneous remission. Canine leproid granuloma syndrome is a common disease in Australia, but is uncommon in dogs in North America. It is caused by a novel, unnamed Mycobacterium species and usually affects the skin and subcutaneous tissues of the head and ears. A diagnosis usually can be made in Wright's-Giemsa and acid-fast-stained cytologic specimens; however, definitive diagnosis requires PCR testing at a specialized laboratory.     

Pure white cell aplasia in a dog

A 3-year-old Irish Wolfhound was evaluated because of acute onset of lethargy and fever. Severe neutropenia (0/microL; reference interval 2500-11,200/microL) was associated with granulocyte aplasia in the bone marrow (myeloid:erythroid ratio, 0.009:1). Antineutrophil antibodies were assessed by an indirect immunofluorescence assay using flow cytometry. When normal canine leukocytes were incubated with the patient's serum and anti-IgG, a marked shift was observed in the forward-angle light scatter of the neutrophil population, and the monocyte cluster disappeared, possibly the result of fragmentation or lysis. Both neutrophil fluorescence intensity (309 +/- 11 median channel units [MCU], control values 107-152 MCU) and the percentage of neutrophils with increased fluorescence intensity (61 +/- 5%, control values 3.8-13.7%) were increased in the patient's serum, consistent with the presence of antineutrophil antibodies. Repeated episodes of neutropenia occurred while treatment with steroidal and nonsteroidal immunosuppressive therapy was initiated and modified. The neutrophil count eventually stabilized in the low-normal range, and the dog was maintained for the next 15 months on prednisone (0.4 mg/kg PO q 48 h) and azathioprine (2 mg/kg daily). During this period, the dog developed immune-mediated hemolytic anemia and thrombocytopenia, decubital ulcers, nasal aspergillosis, and eventually, multi-organ septicemia, which led to euthanasia on day 784. A diagnosis of pure white cell aplasia was made in this dog, based on the many similarities to human patients with pure white cell aplasia, including severe neutropenia with selective granulocyte aplasia, serum antineutrophil antibodies, remission dependent on treatment with immunosuppressive therapy, and recurrent bacterial infections.     

Haematogenous spread of Sporothrix schenckii in cats with naturally acquired sporotrichosis

The recovery of Sporothrix schenckii from blood samples is rare, and the diagnosis of systemic sporotrichosis is usually made at necropsy. In this report, S schenckii was isolated from two or more internal organs of nine necropsied cats with naturally acquired sporotrichosis. Haematogenous spread was demonstrated in vivo by the isolation of S schenckii from the peripheral blood of 17 (n = 49, 34.4 per cent) cats. Feline leukaemia virus (FeLV) was not detected, and co-infection with feline immunodeficiency virus (FIV), observed in nine cases (n = 43, 20.9 per cent), apparently did not affect the isolation of S schenckii from peripheral blood or from the internal organs.     

Systemic infection with Geomyces organisms in a dog with lytic bone lesions

CASE DESCRIPTION: A 5-year-old neutered male mixed-breed dog was evaluated by a veterinarian because of a 4-week history of progressive lethargy and poor appetite; the dog was then examined at a referral hospital. CLINICAL FINDINGS: Hyperglobulinemia was identified via serum biochemical analyses performed before and after arrival at the hospital. Lysis of sternebrae 1 and 2 and sternal lymphadenopathy were detected radiographically. Fine-needle aspirates were collected from the affected sternebrae and lymph node for cytologic examination; findings were consistent with pyogranulomatous inflammation associated with fungal infiltrates. Geomyces organisms were identified via microbial culture of sternebral aspirates. TREATMENT AND OUTCOME: Treatment consisted of oral administration of itraconazole. After 6 months, remodeling of the affected sternebrae and resolution of sternebral lysis were evident radiographically. Geomyces organisms and pyogranulomatous infiltrates persisted despite clinical improvement. Treatment with itraconazole was continued for an additional 3 months. CLINICAL RELEVANCE: Infection with Geomyces organisms is typically localized to the skin and nail beds. In the dog of this report, systemic dissemination of Geomyces organisms resulted in lysis of the first 2 sternebrae. Cytologic examination of fine-needle aspirates and microbial culture of samples of the affected sternebrae were important diagnostic tests for successful identification of the organism. Despite 6 months of itraconazole administration and evidence of clinical improvement, fungal organisms persisted in the dog's affected sternebrae. Practitioners should include Geomyces infection among the differential diagnoses for suspected systemic mycosis and should perform cytologic examination and microbial culture of affected tissue throughout treatment of affected dogs.     

Basal cell tumor or cutaneous basilar epithelial neoplasm? Rethinking the cytologic diagnosis of basal cell tumors

A 1-cm-diameter, red, raised, cutaneous mass over the dorsal surface of the left third metacarpal of a 6-year-old neutered male yellow Labrador Retriever was aspirated. The aspirate contained cohesive clusters of cells, some containing cells with increased pleomorphism. Cellular debris (some keratinized), melanin, large numbers of macrophages, a few neutrophils, and fibroblasts were also observed. The cytologic interpretation was malignant neoplasia with histiocytic inflammation. Differentials included a carcinoma or, given the melanin pigment and variable morphology of the cells, possibly malignant melanoma. Histologically, the tumor was diagnosed as a basal cell epithelioma. Neoplasms that once were lumped into the broad histologic diagnosis of basal cell tumors have since been split into distinct entities, dependent on evidence of differentiation into epidermis, trichofollicular epithelium, or sweat or sebaceous glands. Although histologic reclassification has resulted in removal of most of these entities from the original basal cell tumor category, a cytologic diagnosis of basal cell tumor continues to be used to represent the large, heterogeneous group of epidermal, trichofollicular, and adnexal skin tumors with basal cell characteristics. The case in this report demonstrates the heterogeneity of neoplasms that may be diagnosed cytologically as basal cell tumors and supports the need for cytologic criteria and nomenclature that better reflect potential variation in tissue differentiation.     

Oil Red O-positive lipid in peritoneal fluid from a horse with a rectal tear

A 4-year-old Quarter Horse mare was presented to the Texas A&M University Veterinary Medical Teaching Hospital for evaluation of a rectal tear. On initial evaluation, rectal palpation and colonoscopy revealed a grade IIIb rectal tear. Analysis of peritoneal fluid revealed a modified transudate. Preliminary supportive care included fluid therapy and mineral oil administration via nasogastric tube. Approximately 48 hours after presentation, a second abdominocentesis was performed, and cytologic examination of the fluid revealed a marked suppurative exudate. Round clear nonrefractile material observed within neutrophils and macrophages and in the background stained bright pink to red with Oil Red O, confirming the material as lipid, likely from leakage of mineral oil through the rectal tear. The condition of the mare deteriorated and euthanasia was elected due to the poor prognosis. At necropsy, gross and histologic findings included peritoneal effusion and a full-thickness rectal tear with transmural necrotizing pyogranulomatous colitis and fibrinous peritonitis. To the authors' knowledge, this is the first reported case of Oil Red O-positive lipid vacuoles in the peritoneal fluid of a horse from presumed leakage of mineral oil through a transmural rectal perforation. The frequency of this occurrence in horses is unknown, but it is important for cytopathologists to be familiar with the appearance and significance of lipid-type droplets in phagocytic cells in cytologic fluid analysis specimens.     

Organisms in an aspirate from an ulcerated mass: etiologic agent or mass‐querade?

Smears prepared from a fine-needle aspirate of an ulcerated, dermal mass between the digits of a 9-month-old Bull Terrier puppy revealed a moderately cellular, mixed-cell inflammation with numerous extracellular organisms. The organisms were 3-8 microm in length, curved to oval in shape, with prominent nuclei, and (retrospectively) a rare single, narrow-based bud. The cytologic diagnosis was mycotic dermatitis due to infection with an unusual yeast. Histologic sections of the lesion showed pyogranulomatous inflammation without evidence of an infectious organism. Contamination of the cytologic smears was suspected to have taken place in the clinical pathology laboratory and was confirmed by the isolation of a yeast with identical microscopic features from a cactus located on a windowsill near the work bench. The yeast was cultured and identified as Rhodotorula minuta, an airborne contaminant and ubiquitous saprophyte. It can be difficult to differentiate external contamination from infection when interpreting a cytologic specimen, however, it is important to do so, especially for unusual or opportunistic pathogens.     

Sporotrichosis: a retrospective evaluation of 23 cases seen in northern California (1987–2007)

Sporotrichosis is an uncommon to rare cutaneous and subcutaneous mycosis of animals and humans caused by the dimorphic fungus Sporothrix schenckii . Twenty-three mammalian cases of sporotrichosis examined between 1987 and 2007 at the University of California, Davis – Veterinary Medical Teaching Hospital, were retrospectively evaluated with regard to the historical, clinical, diagnostic and treatment findings. Cats were the most common species affected ( n  = 14). In addition, sporotrichosis was diagnosed in four dogs, four horses and a donkey. Six of 23 cases were diagnosed with the localized cutaneous form of sporotrichosis (four cats, one dog, one horse), 10 with the cutaneous-lymphatic form (four cats, two dogs, three horses and a donkey), and seven with the disseminated form (six cats, one dog). Two of 23 cases did not have skin lesions at the time of diagnosis (one cat, one dog). The most common mode of diagnosis was demonstration of S. schenckii on histopathological evaluation of tissue. In contrast with most previously described sporotrichosis infections in cats, few to no fungal organisms were seen in histopathological samples (haematoxylin and eosin and special stains) in five of the 14 cats. Treatments received included itraconazole (12 cats, one dog), ketoconazole (three dogs), fluconazole (one cat, one donkey), sodium iodide (four horses, one cat) and potassium iodide (one cat, one horse, one donkey). The prognosis for successful treatment was good in all species. Fluconazole was successful in inducing resolution of the cutaneous lesions and controlling the infection in one cat with disseminated sporotrichosis.     

Evaluation of pleural and peritoneal effusions

Certain diseases cause an increase in the amount of fluid present in the pleural and/or peritoneal cavity (an effusion). Uroperitoneum subsequent to kidney, ureter, bladder, or urethra rupture also can cause an increased amount of fluid in the abdomen. Evaluation of fluid samples often is helpful in identifying the mechanism causing the effusion and, occasionally, results in a specific diagnosis. The TP, TNCC, and general cytologic examination can be performed easily, quickly, and inexpensively in-house. The TP and TNCC are used to classify effusions as transudates, modified transudates, or exudates. Transudates usually are caused by hypoalbuminemia, but also can be caused by leakage of fluid from efferent intestinal lymphatics. Cytology and culture usually are not rewarding in the evaluation of transudates. Modified transudates usually are caused by increased vascular permeability or increased intrahepatic hydrostatic pressure. Cytologic and radiographic examinations often are helpful in evaluating patients with modified transudates, while cultures usually are unrewarding. The exudate class encompasses the inflammatory exudates (septic or nonseptic), neoplastic exudates, and chylous effusions. Inflammatory exudates have a high TP and predominantly contain inflammatory cells. They may be septic or nonseptic. When septic, degeneration neutrophils often, but not always, are found. Cultures often are needed to determine whether sepsis is present, to identify the specific organism, and to determine the best therapy. Neoplastic exudates may contain numerous neoplastic cells. If there is concern that the cells are dysplastic instead of neoplastic, the cytology preparation should be referred to a consultant. Chylous effusions usually contain many small lymphocytes with a variable number of neutrophils and macrophages. In chronic chylous effusions, however, neutrophils and/or macrophages may predominate. Chylous effusions usually are differentiated easily from pseudochylous effusions by cytology. Comparison of fluid and serum triglyceride and cholesterol concentrations can be used to differentiate chylous and pseudochylous effusions when differentiation cannot be accomplished by cytology.     

Candida parapsilosis complex infection in a cutaneous lesion from a dog: Spotlight on an opportunistic pathogen of potential increasing importance

Fine-needle aspirates from a 1.5-cm cutaneous mass in a Cocker Spaniel were submitted for cytologic examination. Marked pyogranulomatous inflammation and fungal organisms were present, identified as Candida parapsilosis complex by MALDI-ToF following fungal culture. The fungal infection was considered secondary or an incidental finding, following the diagnosis of a benign keratinizing lesion by histopathologic examination of the excised mass. This case is presented to increase awareness and describe the cytologic features of a potential pathogen, which is of increasing importance in human medicine but has a limited presence in the veterinary literature despite the potential for a similar significance.