A Conscious Minimally Invasive Approach to the Removal of a Trichofolliculoma in an American Guinea Pig: A Case Study.

Trichofolliculomas are the most common nonmalignant cutaneous tumors in guinea pigs. While the treatment of choice is surgical excision, complications may occur with general anesthesia and postoperative healing and discomfort after large tissue resection. We describe a case of a trichofolliculoma treated with a conscious, minimally invasive surgical procedure utilizing injectable lidocaine as local anesthetic, with no complications and excellent cosmetic results.

Three neoplasms in a Eurasian otter (Lutra lutra): malignant melanoma, trichoblastoma and mammary gland adenoma.

An eighteen-year-old female Eurasian otter became emaciated and died. Necropsy examination revealed nose and thoracic cutaneous masses, abdominal subcutaneous mass, and multiple nodules in the liver and lungs. Malignant melanoma was found in the nose cutaneous mass and to have metastasized to the liver, lungs, kidneys, adrenal glands, mammary glands and left mandibular lymph node. The neoplastic cells were labeled for vimentin, melanoma, and S100. The cutaneous mass in the thoracic area consisted of spindle shaped neoplastic epithelial cells and was diagnosed as trichoblastoma. Mammary gland adenoma was observed in the abdominal subcutaneous mass. This is the first report of primary three neoplasms of malignant melanoma, trichoblastoma and mammary gland adenoma in a Eurasian otter.

Pigmented viral plaque and basal cell tumor associated with canine papillomavirus infection in Pug dogs.

Pigmented viral plaque is most commonly seen in Pug dogs in association with canine papillomavirus (CPV). In the present study, nucleic acid sequence and localization of viral genes were examined in 4 cases of pigmented viral plaque in Pug dogs. The results of polymerase chain reaction and nucleic acid sequence analysis showed that the 3 cases with pigmented viral plaque were infected with CPV4, and 1 case with CPV18. In the case with CPV18-positive viral plaque, CPV18 gene was also detected in a lesion of cytokeratin-14- and P63-positive basal cell tumor that developed adjacent to a pigmented viral plaque. Moreover, CPV gene was detected in the squamous cells of pigmented viral plaques and the neoplastic cells of basal cell tumor by in situ hybridization. This is the first report of basal cell tumor associated with CPV18-infection in the dog. Infection of CPV18 may be associated with development of basal cell tumor.

Feline-type cystic basal cell tumor filled with abundant melanin pigment-rich fluid in a dog.

A 2-year-old castrated male mongrel dog presented with a well-demarcated fluctuant dermal mass, located on the back of the neck. Grossly along with cystic structures filled with a black greasy fluid, when cut open. Microscopically, the mass was multi-lobulated. The lobules consisted of neoplastic basaloid cells and showed central degeneration, forming multiple central cystic structures filled with dark melanin-pigmented materials. Immunohistochemically, the neoplastic cells were strongly positive for CK14 and partially positive for CK19, but negative for CK7, CK8/18, CD34, S-100, Melan-A and α-SMA. Based on the findings, the present case was diagnosed as a feline-type basal cell tumor characterized by cystic structures filled with abundant black fluid.

Comparative vaccine-specific and other injectable-specific risks of injection-site sarcomas in cats.

OBJECTIVE: To compare associations between vaccine types and other injectable drugs with development of injection-site sarcomas in cats. DESIGN: Case-control study. ANIMALS: 181 cats with soft tissue sarcomas (cases), 96 cats with tumors at non-vaccine regions (control group I), and 159 cats with basal cell tumors (control group II). PROCEDURES: Subjects were prospectively obtained from a large pathology database. Demographic, sarcoma location, basal cell tumor, and vaccine and other injectable history data were documented by use of a questionnaire and used to define case, control, and exposure status. Three control groups were included: cats with sarcomas at non-vaccine sites, cats with basal cell tumors, and a combined group of cats with sarcomas at non-vaccine sites and cats with basal cell tumors. χ(2) tests, marginal homogeneity tests, and exact logistic regression were performed. RESULTS: In the broad interscapular region, the frequency of administration of long-acting corticosteroid injections (dexamethasone, methylprednisolone, and triamcinolone) was significantly higher in cases than in controls. In the broad rear limb region, case cats were significantly less likely to have received recombinant vaccines than inactivated vaccines; ORs from logistic regression analyses equaled 0.1, with 95% confidence intervals ranging from 0 to 0.4 and 0 to 0.7, depending on control group and time period of exposure used. CONCLUSIONS AND CLINICAL RELEVANCE: This case-control study measuring temporal and spatial exposures efficiently detected associations between administrations of various types of vaccines (recombinant vs inactivated rabies) and other injectable products (ie, long-acting corticosteroids) with sarcoma development without the need to directly measure incidence. These findings nevertheless also indicated that no vaccines were risk free. The study is informative in allowing practitioners to weigh the relative merits and risks of commonly used pharmaceutical products.

Two cases of neoplasia of basal cell origin affecting the axillary region in anseriform species.

Neoplasms of the skin are occasionally seen in domestic birds but are uncommon in nondomestic birds. An 8-year-old male hooded merganser (Lophodytes cucullatus) was presented with bilateral axillary ulcerative lesions that improved but did not resolve with empiric antibiotic and antifungal therapy. Skin biopsies were taken, and bilateral feather folliculomas were diagnosed on histopathologic examination. The duck was euthanatized because of the poor prognosis. A 9-year-old Indian runner duck (Anas platyrhynchos) was presented with an ulcerative lesion, with pseudomembrane and serocellular crust affecting the axillary region. This mass was diagnosed as a basosquamous carcinoma. The mass was surgically excised, and no recurrence was observed. Feather folliculomas are usually considered benign neoplasms in domestic birds and may be primarily ulcerative, exudative, bilateral, and symmetric in location. Basosquamous carcinoma may have a similar gross appearance. It is unknown if the axillary region may be an area with increased incidence of neoplasia in birds. This appears to be the first report of feather folliculoma and basosquamous carcinoma in Anseriforme species. Feather folliculomas and other neoplasms, such as basosquamous carcinoma, should be considered as a differential diagnosis in ulcerative or proliferative skin lesions in birds.

Carcinoma de células basais em periquito australiano(Melopsittacus undulatus): relato de caso / Basal cell carcinoma in budgerigars (Melopsittacus undulatus): case report

As neoplasias do sistema tegumentar são relativamente comuns em aves de cativeiro. Os tumores localizados na derme, emaves de estimação, podem ser de origem epitelial e mesenquimal, sendo que os carcinomas de células basais parecem serextremamente raros em aves. Um periquito macho adulto foi encaminhado a uma clínica particular apresentando uma massatumoral na epiderme, e localizada na região medial do úmero direito. Optou-se pela amputação da asa afetada e o diagnósticode carcinoma de células basais foi feito pela histopatologia.

Tumors of the integumentary system are relatively common in captive birds. Dermal tumors in pet birds can be epithelial andmesenchymal in origin. Basal cells carcinomas appear seem to be extremely rare in birds. An adult male budgerigar wasexamined exhibiting a tumor mass situated at the epidermis and in the medial region of the right humerus. The wing wasamputated and histopathology diagnosis identified basal cell carcinoma.

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.

Clear cell trichoblastomas in two dogs.

Two cases of clear cell trichoblastomas were diagnosed in young dogs. The tumour had ribbons of basaloid cells as seen in ribbon trichoblastomas, as well as differentiation to external root sheath of the hair follicle and few cells with sebaceous differentiation. This is the first report of clear cell trichoblastoma in dogs.

Multicenter case-control study of risk factors associated with development of vaccine-associated sarcomas in cats.

OBJECTIVE: To determine whether particular vaccine brands, other injectable medications, customary vaccination practices, or various host factors were associated with the formation of vaccine-associated sarcomas in cats. DESIGN: Prospective multicenter case-control study. ANIMALS: Cats in the United States and Canada with soft tissue sarcomas or basal cell tumors. PROCEDURE: Veterinarians submitting biopsy specimens from cats with a confirmed diagnosis of soft tissue sarcoma or basal cell tumor were contacted for patient medical history. Time window statistical analyses were used in conjunction with various assumptions about case definitions. RESULTS: No single vaccine brand or manufacturer within antigen class was found to be associated with sarcoma formation. Factors related to vaccine administration were also not associated with sarcoma development, with the possible exception of vaccine temperature prior to injection. Two injectable medications (long-acting penicillin and methyl prednisolone acetate) were administered to case cats more frequently than to control cats. CONCLUSIONS AND CLINICAL RELEVANCE: Findings do not support the hypotheses that specific brands or types of vaccine within antigen class, vaccine practices such as reuse of syringes, concomitant viral infection, history of trauma, or residence either increase or decrease the risk of vaccine-associated sarcoma formation in cats. There was evidence to suggest that certain long-acting injectable medications may also be associated with sarcoma formation.

Caracterización de las Regiones Organizadoras Nucleolares coloreadas con Plata (AgNORs) en tumores cutáneos caninos / Nucleolar organized regions in canine cutaneos tumors

Se utiliza una técnica de coloración con plata para visualizar las Regiones Organizadoras Nucleolares (AgNORs). La evaluación cuantitativa y cualitativa de estas regiones representa en la actualidad un marcador de actividad proliferativa en células tumorales. El presente estudio tuvo como objetivo caracterizar las AgNORs en algunos tipos de tumores cutáneos caninos, para lo cual se evaluaron 28 mastocitomas, 18 carcinomas espinocelulares y siete epiteliomas basocelulares, procedentes del archivo de Patología Animal y del Consultorio Veterinario de la Universidad de Antioquia, y de otros consultorios de la ciudad de Medellín, Colombia. Las muestras bloqueadas en parafina se cortaron a cuatro micras, y se colorearon con Hematoxilina-Eosina y Giemsa paradiagnosticar y clasificar los mastocitomas. Se utilizó otra serie de cortes coloreados con plata para evaluar morfométricamente las AgNORs utilizando un Sistema Automático Analizador de Imágenes (SAAI). Se evaluaron los parámetros: área nuclear, área AgNORs/célula, número de AgNORs/ célula, y distribución AgNORs en la célula. Para determinar el número de células a evaluar se utilizó el estudio de variación de la inestabilidad de los valores medios, con relación al tamaño de la muestra;se obtuvo un mínimo representativo de 20 células por caso para los mastocitomas y los carcinomas espinocelulares, y de 30 células por caso, para los tumores basocelulares. Los datos fueron analizadosestadísticamente mediante el análisis de varianza (ANOVA) y se compararon las medias por el test de Fischer (F) empleando un nivel de significancia de p<0.05. La coloración AgNORs fue factible en lostumores evaluados para lo cual se necesitaron de 30 minutos en el período de incubación. El análisis estadístico mostró que los mastocitomas grado II poseen un área nuclear menor estadísticamentesignificativa (p<0.05). Existe además, diferencia estadística significativa (p<0.05) en el número y en el área de las AgNORs entre los tres grados hi...

Bax/bcl-2: cellular modulator of apoptosis in feline skin and basal cell tumours.

Bcl-2 and bax are two members of the BCL-2 gene family that play a prominent role in the regulation of apoptosis. Bax and bcl-2 expression were examined immunohistochemically in normal (healthy) feline skin and in 24 benign feline cutaneous basal cell tumours. The tumours were also examined for cellular proliferation by measurement of reactivity for the proliferation marker Ki-67, and for apoptosis by in-situ labelling for fragmented DNA. Bcl-2 was detected in normal basal epithelium and in 23 of 24 basal cell tumours. Bax was detected in both basal and suprabasal epithelium, but in only seven of 24 tumours. For tumours that expressed both bax and bcl-2, the bax:bcl-2 ratio was low. Neither bax nor bcl-2 expression was detected in 14 feline cutaneous squamous cell carcinomas. Basal cell tumours showed modest cellular proliferation (median, 17.5% Ki-67- reactive cells), but few (less than 1%) apoptotic cells. The slow, indolent growth of feline cutaneous basal cells in these benign skin tumours may be a response, at least in part, to opposing regulatory expressions of bcl-2 and bax.

Equine basal cell tumors: 6 cases (1985-1999).

Basal cell tumors are rare benign tumors in horses. Over a 15-year period, 6 horses were diagnosed with basal cell tumors. The tumors were well-circumscribed. freely moveable, firm, raised papules, nodules, or masses that ranged from 0.6 to 5 cm in diameter. Five of the 6 tumors were ulcerated. Based on gross appearance, the tumors were diagnosed as sarcoids, and 1 was diagnosed as a melanoma. The range of age of affected horses was 6-26 years. The tumors were identified clinically 1 week to 3 years before excision. In 4 horses for which information was available, complete surgical excision was curative with no recurrence 4 months to 2 years after removal.

Immunohistochemical analysis of cyclin A, cyclin D1 and P53 in mammary tumors, squamous cell carcinomas and basal cell tumors of dogs and cats.

The involvement of cyclin A, cyclin D1 and p53 proteins in canine and feline tumorigenesis was analyzed immunohistochemically. In the present study, a total of 176 cases were examined, among which there were 108 canine cases (75 mammary lesions, 16 squamous cell carcinomas and 17 basal cell tumors) and 68 feline cases (43 mammary lesions, 20 squamous cell carcinomas and 5 basal cell tumors). Speckled nuclear staining for cyclin A was observed in 19/38 (50%) canine malignant mammary tumors and 18/37 (48.6%) feline mammary carcinomas, while this was not seen in benign mammary tumors of either dogs or cats. Marked intense nuclear cyclin A staining was seen in 7/16 (43.8%) canine squamous cell carcinomas and 18/20 (90.0%) feline squamous cell carcinomas. Only 3/17 (17.6%) canine basal cell tumors showed slight and scattered staining for cyclin A. Expression of cyclin D1 was very rare in both canine and feline tumors. Nuclear staining of p53 was found in 7/37 (18.9%) feline mammary carcinomas. Intense immunoreactivity for p53 was found in 6/16 (37.5%) canine squamous cell carcinomas and 8/20 (40%) feline squamous cell carcinomas. These results suggest that cyclin A may have a role in the proliferation of canine malignant mammary tumors, feline mammary carcinomas and squamous cell carcinomas of dogs and cats, and p53 may associate with the tumorigenesis of feline mammary carcinomas and squamous cell carcinomas of dogs and cats.

Simultaneous seminoma and interstitial cell tumour in a rabbit with a previous cutaneous basal cell tumour.

The development of spontaneous multiple tumours is a rare event in domestic rabbits. The diagnosis of a cutaneous basal cell tumour and the successive development of simultaneous bilateral testicular tumours with dissimilar histology (a seminoma and an interstitial cell tumour) are described in a vasectomized, crossbred dwarf rabbit, aged 6 years. Two cases of basalioma associated with uterine adenocarcinoma have been previously described in rabbits. A similar association between basal cell neoplasia and development of tumours (e.g., testicular and breast cancer) at cutaneous and non-cutaneous sites has been reported in man.

Malignant basal cell tumor in a Djungarian hamster.

A malignant basal cell tumor was found in the skin of the abdomen of a female Djungarian hamster of unknown age and weighing 40 g. Histologically, the tumor mass was composed of cells resembling the basal cells of the epidermis, and these cells exhibited solid type proliferation. In the tumor tissue and necrotic foci, horn cysts were observed. Immunohistochemically, cytokeratin was present in the tumor cells and horncysts. By electron microscopic examination, the tumor cells had scanty cell organelles and a few desmozomes. This paper describes a rare malignant basal cell tumor in a Djungarian hamster.

Tumors of the skin and associated structures.

Because of the location of skin tumors, afflicted dogs and cats are frequently presented to veterinarians for examination. The location also facilitates the use of radiation therapy for patients with skin tumors. Few animals treated with radiation therapy for skin tumors experience significant toxicity. Animals with a variety of skin tumors can benefit from treatment with radiation therapy. These tumors include mast cell tumors, squamous cell carcinoma, tumors of the digit, tumors of the ear canal, tumors of the cutaneous adnexa, mammary gland tumors, plasma cell tumors, cutaneous melanoma, cutaneous hemangiosarcoma, and transmissible venereal tumors. The prognosis for individual patients varies with the tumor type and, in some cases, with the stage of the disease.

Mitotic phase distribution, mitotic activity and apoptosis in basal cell tumours of canine skin.

This study evaluates the mitotic phase distribution, mitotic activity and apoptosis in 17 basal cell tumours of canine skin. The number of mitotic and apoptotic cell/mm2 of neoplastic epithelium is counted and the volume corrected mitotic and apoptotic index, respectively, are obtained (M/V and A/V index). Transmission electron microscopy is performed on selected cases to confirm the typical features of apoptosis. The M/V index ranges from 9 to 45/mm2 of neoplastic epithelium, while the A/V index ranges from 5 to 111/mm2 of neoplastic epithelium. Even if the number of apoptotic cells is slightly higher than that of mitotic cells and vice versa, the mean values of the two parameters (mean M/ V = 20.76 +/- 10.86, mean A/V = 31.41 +/- 24.53) tend to be equal. In fact, apoptotic and mitotic index are not statistically different (P = 0.11). Furthermore, in all the samples examined, an increased proportion of metaphases (46.82%) is observed. These findings suggest that the discrepancy between apparent mitotic activity and tumour growth may be mainly due to the increased duration of the entire cell cycle rather than to the high incidence of apoptosis.