Multiple feather follicle cysts in a Moroseta hen (Gallus gallus)

An 8-month-old white feathered, black skinned Moroseta hen was presented for examination because of numerous 2 mm- to 30 mm-diameter irregularly shaped, hard nodules in the skin of the head, wings, back, and abdomen. The nodules were confined to the skin and did not involve subcutaneous tissues. Nodules consisted of dilated feather follicles packed with a caseous tan-to-pale-yellow material admixed with feather remnants. Histologically, affected feather follicles were markedly dilated and filled with laminated keratin debris. Necrosis of the epidermis and perifollicular lymphocyte infiltration was also present. Bacteriologic investigation of internal organs was negative, while secondary bacteria, Proteus spp. and Bacillus spp., were isolated from skin nodules. A concomitant lice infestation of Menopon spp., as well as leg mange caused by Cnemidocoptes spp., were also present. These bacterial isolates and parasites were not related to the disease condition. The condition observed was differentiated from benign feather follicle tumors, and a diagnosis of multiple feather follicle cysts was made. In addition, a breed predisposition was hypothesized.     

Acantholytic folliculitis and epidermitis associated with Staphylococcus hyicus in a line of white Leghorn laying chickens

Several mature Leghorn-type hens with the same genetic background experienced skin and feather problems in a breeder flock. There was almost-total feather loss on the head and neck, as well as thickened, scaly skin, and follicular ostia were plugged with keratin debris. Other individuals exhibited prominent subcutaneous nodules multifocally on the head. Histologic examination of the skin revealed a severe hyperplasia of follicular epithelium with hyperkeratosis and cystic dilation. Numerous clefts and vesicles were detected along the epidermis and follicular epithelium, some containing acantholytic keratinocytes. A mild heterophilic inflammation was associated with these lesions, and few gram-positive cocci were present in the keratin plugs. Bacterial culture of the skin yielded a variable amount of Staphylococcus hyicus. Immunochemistry looking for chicken IgY revealed no intercellular staining in the epidermis or follicular epithelium. All these findings supported a diagnosis of Staphylococcus-associated acantholytic epidermitis and folliculitis. This case suggests that S. hyicus could be a significant pathogen in poultry production. The close genetic relationship among affected individuals could indicate a hereditary predisposition in this line of White Leghorn laying chickens.     

Combined excision and intralesional bevacizumab for sebaceous carcinoma of the eyelid in an Amur tiger (Panthera tigris altaica)

An 18‐year‐old zoo‐kept female Amur tiger presented with an approximately 5 mm diameter lateral canthal eyelid mass in the left eye which grossly appeared red and irregular. The mass was completely excised via lateral canthoplasty. Histopathologic evaluation was consistent with a diagnosis of sebaceous cell carcinoma, which is a potentially aggressive cutaneous neoplasm. The sebaceous carcinoma recurred within 3 months and slowly increased in size until a second surgical excision was performed 9 months following the first surgery. The second surgical excision was combined with intralesional injection of 10 mg of the antiangiogenic drug bevacizumab. Histology confirmed the diagnosis. The tiger was euthanized 16 months postoperatively for reasons unrelated to, and without recurrence of, the eyelid neoplasm. At postmortem, no gross periocular or metastatic lesions were noted, and histopathology of the lateral canthus provided no evidence of recurrence. Surgical excision combined with intralesional bevacizumab treatment induced life‐long resolution of the sebaceous carcinoma. Bevacizumab treatment may be associated with the regression of periocular angiogenic proliferative conditions, including neoplasia, by inhibiting angiogenesis.     

Cowpox in cats

Orthodox virus infection of domestic cats in the United Kingdom was first reported in 1978. Outbreaks of a disease considered to be due to cowpox (orthopox) infection had been reported in a number of species of zoo animals in Europe between 1971 and 1977 and a serious outbreak occurred among cheetahs in a United Kingdom zoo. In this species the clinical signs were ülcerating and crusted skin lesions, in some cases complicated by respiratory signs and death. An increasing number of cases of pox infection of domestic cats has been reported in Great Britain. Affected animals have shown ulcerating and crusted skin lesions particularly of the head and limbs; systemic illness was uncommon. Immunologically compromised cats, ie, FeLV positive or those receiving corticosteroid of megestrol acetate therapy, were found to be more likely to show extensive or generalised pox lesions. The source of infection is thought to be small wild mammals, ie, voles, acting as a reservoir of virus, which are preyed upon by domestic cats. Feline orthopox virus infection is a zoonosis. Transmission of the disease from affected cats to incontact owners has been reported from Great Britain and the continent of Europe. The differential diagnosis of the condition in cats includes those skin disorders commonly treated with steroidal anti-inflammatory preparations. Definite diagnosis is important as these drugs are contraindicated in viral infections. Confirmation of diagnosis may be by virus isolation and serology. Histological examination of skin biopsy specimens is also helpful. Whether or not the causal agent of this disease should be referred to as cowpox virus or feline orthopox virus continues to be a matter of debate.     

An epornitic of avian pox in a research aviary

An outbreak of avian pox in a bird research colony was reported. Although 10 species of passerine birds were housed within the facility, clinical signs and mortality were restricted to canaries and house sparrows. Post-mortem lesions initially occurred in the upper and lower respiratory tracts and were characterized by proliferative rhinitis, proliferative bronchopneumonia, and proliferative airsacculitis, and diphtheritic lesions occurring in the esophagus were characterized by proliferative granulomatous esophagitis. Cutaneous lesions occurred subsequently in some birds, and a diagnosis was made by histopathology, electron microscopy, and virus isolation. The occurrence of diphtheritic lesions in pox infections of wild birds has been rare, and a sparrow showed an unusual combination of both diphtheritic and acute systemic lesions previously undescribed.     

Ultrasonographic appearance of torsion of a testicular seminoma in a cryptorchid dog

An intra-abdominal testicular tumour was diagnosed in a 10-year-old, male, cryptorchid golden retriever. Upon surgical removal, torsion of the testis was found. The histopathological diagnosis was seminoma. The ultrasound examination in this case revealed a parenchymal mass lesion. An ultrasound examination is a useful supplemental diagnostic tool for differentiation of abdominal mass lesions.     

Squamous cell carcinoma of the footpad with systemic metastasis in a captive crowned solitary eagle (Buteogallus coronatus)

Squamous cell carcinomas (SCC) are one of the most common tumors of the tegument that can have a misdiagnosis of chronic skin wounds. An adult captive crowned solitary eagle presented an indolent wound-like ulcer on the footpad and a fatal outcome. An infiltrating tumoral mass in the foot and multiple tumoral metastatic nodules in visceral organs were detected. The neoplasm was composed of atypical squamous cells with strong positivity for cytokeratin, “keratin pearl” structures, and marked invasion of tissues confirming a diagnosis of metastatic SCC. This might be the first report of an SSC with metastasis on the footpad in a captive Chaco eagle, which is one of the endangered species of birds of prey.     

Disseminated haemangiosarcoma in an eastern barred bandicoot (Perameles gunnii)

A captive adult male Eastern barred bandicoot (Perameles gunnii) presented with three palpable subcutaneous masses in November 1998. A diagnosis of haemangiosarcoma was made based on histological examination of one excised mass. Euthanasia of the animal was performed 11 days postsurgery and a proliferative lesion in the paralumbar musculature and similar, smaller proliferative lesions surrounding the right popliteal lymph node and in the ventricular wall of the heart were found. Metastatic lesions were found in the liver and lung. The histological features of the neoplastic tissues supported the diagnosis of a poorly differentiated, disseminated haemangiosarcoma. This is the first reported case of haemangiosarcoma in the Eastern barred bandicoot.     

Pleomorphic sarcoma with giant cells infiltrating the infraorbital canal in an aged Thoroughbred mare

A 27-year-old Thoroughbred mare presented for computed tomography (CT) of the head following a 3-month history of facial swelling at the infraorbital foramen, unilateral self-mutilation and head-shaking. Standing CT imaging showed soft tissue attenuation surrounding the infraorbital canal, with extensive bony lysis of the canal and maxillary bone at the infraorbital foramen. The mare was subjected to euthanasia, and post-mortem examination revealed a proliferative tan soft tissue mass overlying the infraorbital nerve. A histopathological diagnosis of pleomorphic sarcoma with giant cells was made. Immunohistochemical analysis failed to fully elucidate the mesenchymal cell of origin of the sarcoma. Pleomorphic sarcoma with giant cells involving the infraorbital canal of the horse has not been previously described. This case highlights chronic subtle behavioural changes attributable to this neoplasm prior to the development of clinical signs and the utility of advanced imaging in the diagnosis.     

Cutaneous melanophoroma in a green iguana (Iguana iguana)

An adult, male, green iguana (Iguana iguana) of unknown age was presented with a history of an enlarging, dark, skin mass in the right axillary region. The mass was excised because neoplasia was suspected. Impression smears of the cut surface of the mass were prepared for cytologic examination, and the mass was fixed for histologic examination. The impression smears contained numerous, discrete, pigmented, neoplastic cells consistent with melanin-producing neoplastic chromatophores. Histologic findings were consistent with a cutaneous melanophoroma. By transmission electron microscopy, the intracytoplasmic pigment granules corresponded to numerous melanosomes and lower numbers of premelanosomes. Tissue sections of the tumor were immunoreactive for Melan A antigen and were negative for S-100 antigen. The cytologic, histologic, electron microscopic, and immunohistochemical findings of the neoplasm were consistent with those of melanophoroma, an uncommon neoplasm of reptiles. The present report augments the limited body of knowledge on cytomorphologic and immunohistochemical characteristics of pigmented neoplasms in reptiles.     

Conjunctival mucinous adenocarcinoma in an ostrich (Struthio camelus)

A 2‐year‐old male ostrich (Struthio camelus) presented with a rapidly growing soft tissue mass protruding from the ventromedial aspect of the right eye (OD). The initial physical examination revealed a soft tissue mass attached to the medial inferior conjunctiva. The mass was excised with cryosurgery, and the conjunctival tissue margins were treated with cryoablation. Histopathological examination diagnosed granulomatous inflammation associated with scattered acid‐fast bacteria. The ostrich recovered uneventfully and appeared healthy until recurrence of a grossly similar mass 2 months later. Gross examination revealed a botryoid mass attached to the inferior palpebral conjunctiva and extending onto the palpebral aspect of the nictitating membrane. Euthanasia was selected, and the histological diagnosis of the second mass was a mixed mucinous adenocarcinoma; however, no acid‐fast bacteria were seen. Granulomatous conjunctival lesions have been previously described in the ostrich, while, to the authors' knowledge, neoplastic conjunctival lesions have not. Neoplasia should be considered as a differential diagnosis for a rapidly recurring, granulomatous conjunctival mass in this species.     

Clinical utility of a complete diagnostic protocol for the ocular evaluation of free-living raptors

Objective: To describe a protocol for the examination of free‐living raptors and report the ophthalmic examination findings of seven raptor species native to central Illinois, namely the barred owl, Cooper’s hawk, eastern screech owl, great horned owl, American kestrel, red‐tailed hawk, and turkey vulture and to determine if the findings relative to visual prognosis affected eligibility for future release. Animals studied: Seventy‐nine free‐living raptors. Procedures: Under manual restraint, complete ophthalmic examination including slit‐lamp biomicroscopy and indirect funduscopy, applanation tonometry, rebound tonometry, ocular morphometrics, B‐mode ultrasound, and electroretinography (ERG) were performed on each bird. Histopathology of enucleated globes was performed after euthanasia or death in selected cases. Results: The examination protocol was easily performed using manual restraint alone on all birds. Ocular lesions were detected in 48.1% of birds, with 47.3% affected unilaterally and 52.6% affected bilaterally. Ocular lesions were considered to be vision threatening in 29.0% of the unilaterally affected birds and 29.0% of the bilaterally affected birds. The most common case outcomes were discharge from hospital to rehabilitation facility (45.6%) followed by euthanasia (43.0%). The presence of an ocular lesion or a vision‐threatening ocular lesion was not significantly associated with outcome. Reference ranges are reported for B‐mode ultrasound, ocular morphometrics, and horizontal corneal diameter in all species. Conclusion: Complete ophthalmic examination can be supplemented by the use of ocular morphometrics, ultrasound, and ERG in the manually restrained raptor. These advanced diagnostic techniques may be useful in developing more objective criteria for evaluating eligibility for release following rehabilitation of free‐living birds of prey.     

Recurrent localised cutaneous parapoxvirus infection in three cats

CASE HISTORY: Three cats were presented with single proliferative lesions affecting one foot, which failed to heal after medical treatment, and recurred despite surgical resection. PATHOLOGICAL FINDINGS: Histologically, the lesions were proliferative and papillary. There was marked acanthosis, rete peg formation, and compact orthokeratosis, with large numbers of bacteria in the orthokeratotic scale. Some biopsies had multifocal keratinocyte swelling of the stratum granulosum, and amphophilic intracytoplasmic inclusions were present in some of the swollen cells. The dermis consisted of a light fibrous stroma with marked capillary proliferation. Parapoxviruses were detected in the lesions of all cats by electron microscopic examination. PCR analysis detected orf virus (contagious ecthyma virus) in two cats, and orf virus was cultured from one cat. DIAGNOSIS: Parapoxvirus infection in cats. CLINICAL RELEVANCE: Parapoxvirus infection should be considered as a differential diagnosis when dealing with proliferative, non-healing lesions on the feet of cats, especially cats in rural areas. The recovery of orf virus from a cat with typical poxvirus lesions extends the range of species affected by this virus.     

Conjunctival-corneal intraepithelial neoplasm in an Asian elephant (Elephas maximus).

An adult female Asian elephant (Elephas maximus) presented with an enlarging nasal limbal mass of the left eye. The mass was excised and the surgical bed treated with liquid nitrogen cryotherapy. Histopathologic examination of the excised tissue showed the mass to be a superficial dysplastic ocular lesion, or conjunctival intraepithelial neoplasm. A 5-yr follow-up period has passed without complications or recurrence, suggesting that as is the case in humans (Homo sapiens), excision and cryotherapy is an effective treatment for these lesions in elephants. This is the first report of any ocular neoplasia in an elephant.     

Marek's disease virus-induced skin leukosis in scaleless chickens: tumor development in the absence of feather follicles

Marek's disease virus (MDV) is an oncogenic cell-associated herpesvirus that causes T-cell lymphoma in chickens. Lymphoproliferative neoplasms in Marek's disease (MD) occur in various organs and tissues, including the viscera, peripheral nerves, skin, gonads, and musculatures. MDV is restrictively produced in the feather follicle epithelial (FFE) cells, and it gains access to the external environment via infected cells or as infectious enveloped cell-free virus particles. The goals of the present study were to 1) determine whether the MDV-induced skin lesions are neoplastic in nature or inflammatory reactions to viral infection, 2) determine whether physical presence of feather follicles (FF) is necessary for skin tumor development, and 3) study the role of skin epithelial cells not associated with feathers or FF in the replication and dissemination of infectious virus particles. Scaleless chickens that produce only a few scattered feathers and no sculate scales along the anterior metatarsi were used as a unique model to study the pathogenesis of dermal lesions. Histologic and immunohistochemical analysis revealed that the cutaneous lesions were tumorous as was manifested by massive accumulation of lymphoblasts and extensive activation of meq oncoprotein, the hallmark of MDV oncogenesis, within the skin lesions. Neoplastic cutaneous lesions in the scaleless chickens indicate that feather follicles are not necessary for skin tumor development. Finally, our preliminary data indicate that inoculation with supernatant fluid from homogenized and sonicated skin samples of MDV-infected scaleless chickens induces MD in susceptible birds, suggesting that skin epithelial cells not associated with FF also harbor infectious viral particles.     

Pseudomycetoma caused by Microsporum canis in a Persian cat: lack of response to oral terbinafine.

An eight-year-old neutered female Persian cat with a four-year history of relapsing skin disease, characterised by ulcerated nodules with a yellow granular discharge, was examined. A diagnosis of granulomatous dermatitis and panniculitis (pseudomycetoma) caused by Microsporum canis was made on the basis of history, clinical signs, histopathological examination of skin biopsy specimens and culture of macerated tissue. Because previous therapy, comprising repeated surgical excision and the administration of griseofulvin and itraconazole, had not been successful, terbinafine was administered for an eight-month period. However, lesions progressed despite this treatment and the cat was euthanased.     

Multiple dermoid sinuses of type Vb and IIIb on the head of a Saint Bernard dog

Dermoid sinus, a congenital malformation of neural tube development, has been reported in humans and several animal species including dogs. It is typically found in the dorsal midline and commonly occurs in the Rhodesian Ridgeback breed. A case of multiple dermoid sinuses in the fronto-occipital region is described. An 11-month-old, intact female Saint Bernard dog was presented with a 2 day history of discharge from a large irregular subcutaneous mass in the fronto-occipital region. The dog was otherwise healthy. The dog had two circular skin lesions (approximately 4 × 4 and 4 × 2 cm diameter) surrounded by multiple irregular elevated masses. The masses had multiple small openings on the skin surface with tufts of hair protruding from the apertures. The masses were surgically removed, and the diagnosis of multiple dermoid sinuses was confirmed by histological examination. Histopathological examination showed multiple, variably sized, spherical to tubular cysts expanding the dermis and subcutis. Cysts were filled with hair shafts and lamellar keratin and were lined by a stratified squamous epithelium. Sebaceous and apocrine gland adnexal structures were also observed. To the best of our knowledge, this is the first reported case of multiple dermoid sinuses of two different types in the head of a Saint Bernard dog.     

Unilateral distension of the tarsal sheath in the horse: a report of 11 cases

Eleven horses with unilateral distension of the sheath are reported with emphasis on the use of plain and contrast radiography in diagnosis. Six had associated bony abnormalities of the sustentaculum tali, and two of these showed destructive or mixed destructive and proliferative lesions resulting from osteomyelitis. One horse had a fracture of the sustentaculum. In three horses proliferative changes were found. Bony changes were best demonstrated on a dorsomedial-plantarolateral oblique view. Contrast radiography of the tarsal sheath was performed in five cases without, and two horses with, associated bony lesions. In five cases ballooning with or without folding of the proximal aspect of the sheath was demonstrated. Additional band-like filling defects (two cases), triangular filling defect (one case), nodular intra-tendovaginal masses (two cases), or an extra-tendovaginal mass (one case) were noticed. The remaining two horses showed a semicircular collar shape dilation of the proximal aspect of the sheath. Contrast radiography appeared to be a helpful tool for the examination of tarsal sheath lesions. Two horses with associated bony changes were destroyed immediately after diagnosis, one failed to recover following surgical intervention and in three horses the outcome was unsatisfactory after conservative treatment. Three horses without associated bony lesions recovered completely after conservative treatment. One was operated on subsequently; the results are promising but the outcome of this case is not yet known. One was sold shortly after diagnosis and lost to follow up.     

Atypical distribution of fowl pox lesions in broilers

An unusual cutaneous fowl pox outbreak occurred in 8-wk-old broilers in California. Rounded and longitudinal, proliferative scratch-associated lesions were found only in feathered areas of the body. Both sides of the hip, the lower abdomen, pericloacal area, and lateral lower neck area were involved. The head, legs, feet, and toes did not have lesions. Birds in only one section of one of five houses were affected. Fifteen percent condemnations occurred in birds from the affected house due to the skin lesions. A diagnosis of fowl pox was achieved by histopathology, viral isolation, and direct electron microscopy. The unusual distribution of pox lesions was assumed to be associated with skin scratches. There was no evidence that mosquitoes or other types of insects were involved in this outbreak. To the knowledge of the authors, this is the first report of this kind of unusual fowl pox in the United States.