Ichthyosiform dermatosis in a Soft-Coated Wheaten Terrier

Abstract A Soft-Coated Wheaten Terrier with an ichthyosiform dermatosis is described. Patches of thick, scaly skin were apparent from birth and progressed in extent as the dog aged. At 3 months of age, the scaling was generalized and was accompanied by a greasy exudation which matted the haircoat. The skin was greasy and there was generalized scaling, but the skin of the head and pinnae of the ears was most affected. There was minimal involvement of the foot-pads. Microscopically, the skin had patchy áreas of ortho-and parakeratotic hyperkeratosis, follicular keratosis, superficial perivascular dermatitis, and variable hypergranulosis. Electron microscopical findings were consistent with proliferative hyperkeratosis. The dog did not respond to treatment with benzoyl peroxide shampoos, humectant sprays, and isotretinoin. Comparative features of skin diseases similar to this canine ichthyosiform dermatosis are discussed. Résumé— Une dermatose ichtyosiforme est observée sur un Soft-Coated Wheaten Terrier. Des zones cutanées squameuses et épaissies apparues dès la naissance s'étendent avec l'âge. A l'âge de 3 mois, l'état squameux est généralisé et associé avec une séborrhée grasse qui collent les poils entre eux. Les lésions sont généralisées avec toutefois un prédilection pour la face et les pavilions auriculaires. Les lésions podales sont peu importantes. Les lésions histopathologiques sont caractérisées par une hyperkératose orthokératosique et parakératosique, une kératose folliculaire, une dermite périvasculaire superficielle et une hypergranulose variable. La microscopic électronique montre une hyperkératose proliférative. Le chien n'a pas répondu aux shampooings au peroxyde de benzoyle, aux sprays hydratants et à risotrétinoi'ne. Les aspects comparés de cette dermatose ichtyosiforme sont discutées. [Helman, R. G., Rames, D. S., Chester, D. K. Ichtyosiform dermatosis in a Soft-Coated Wheaten Terrier. (Dermatose ichtyosiforme sur un Soft-Coated Wheaten Terrier.) Veterinary Dermatology 1997; 8 : 53–58.] Resumen Se describe una dermatosis ictiosiforme en un Soft Wheaten Terrier. Desde el nacimiento presentaba áreas de piel descamativa y engrosada que se extendieron con la edad. A los tres meses, la descamación era generalizada y se acompañaba de un exhudado oleoso que enmarañaba el pelo. La piel se encontraba oleosa y habia descamación generalizada, siendo la piel de la cabeza y pabellones auriculares la más afectada. Los cojinetes se encontraban poco afectados. Microscopicamente la piel presentaba áreas dispersas de hiperqueratosis orto-y paraqueratótica, queratosis folicular, dermatitis perivascular superficial e hipergranulosis variable. Los hallazgos ultraestructurales fueron compatibles con una hiperqueratosis proliferativa. El perro no respondió a un tratamiento con champú de peróxido de benzoilo, esprais humectantes e isotretinoina. Se discuten aspectos comparativos de enferemedades cutáneas similares a esta dermatosis ictiosiforme canina. [Helman, R. G., Rames, D. S., Chester, D. K. Ichthyosiform dermatosis in a Soft-Coated Wheaten Terrier. (Dermatosis ictiosiforme en un Soft Wheaten Terrier.) Veterinary Dermatology 1997; 8 : 53–58.] Zusammenfassung— Es wird eine ichthyosiforme Dermatose bei einem Soft Coated Wheaten Terrier beschrieben. Von Geburt an waren Bezirke mit dicker, schuppiger Haut sichtbar, die sich in der Ausdehnung mit zunehmendem Alter der Hundes vergrößerten. Im Alter von drei Monaten war die Schuppenbildung generalisiert und wurde von einer schmierigen Exsudation begleitet, die das Haarkleid verklebte. Die Haut war schmierig und das Schuppen generalisiert, jedoch war die Haut am Kopf und den Ohren am stärksten betroffen. Die Pfotenballen waren nur minimal miteinbezogen. Bei der mikroskopischen Untersuchung zeigte die Haut herdförmige Bezirke von ortho-und parakeratotischer Hyperkeratose, follikulärer Keratose, oberflächlicher perivaskulärer Dermatitis und variabler Hypergranulose. Die elektronenmikroskopischen Befunde gingen mit der proliferativen Hyperkeratose konform. Der Hund sprach auf die Behandlung mit Benzoylperoxid-Schampoos, feuchigkeitsspendenden Sprays und Isotretinoin nicht an. Vergleichbare Erscheinungen von Hauterkrankungen, die dieser caninen ichthyosiformen Dermatose ähneln, werden diskutiert. [Helman, R. G., Rames, D. S., Chester, D. K. Ichthyosiform dermatosis in a Soft-Coated Wheaten Terrier. (Ichthyosiforme Dermatose bei einem Soft Coated Wheaten Terrier.) Veterinary Dermatology 1997; 8 : 53–58.]     

Ultrasound is a poor predictor of early or overt liver or spleen metastasis in dogs with high‐risk mast cell tumours

Conflicting evidence exists regarding the importance of routine abdominal ultrasound (US) with hepatic and splenic fine needle aspiration (FNA) cytology during staging of canine mast cell tumours (MCT). The objective of this study was to correlate ultrasonographic and cytologic findings in dogs with strictly defined high‐risk MCTs and to determine the influence on outcome. Our hypothesis was that US poorly predicts visceral metastasis in high‐risk MCTs and that early metastasis is associated with improved outcome when compared to overt metastasis. US of liver and spleen correlated to cytologic results, categorized as no metastasis, early metastasis or overt metastasis. Of 82 dogs prospectively enrolled, 18% had early visceral metastasis and 7% had overt metastasis on cytology; 67% with visceral metastasis had regional LN metastasis. US was a poor predictor of metastasis with sensitivity, specificity, positive predictive value and negative predictive value for the spleen of 67%, 68%, 21% and 94%, respectively and for the liver of 29%, 93%, 56% and 82%, respectively. Median time to progression (TTP) for dogs with no metastasis, early metastasis and overt metastasis was not reached, 305 and 69 days, respectively (P < .001). Median survival time (MST) for the 3 groups were not reached, 322 and 81 days, respectively (P < .001). High Patnaik or Kiupel grade, early metastasis, overt metastasis and adequate local control were significantly associated with outcome. Early visceral metastasis was associated with poorer outcome compared to dogs without metastasis, however, a subset of dogs experienced long‐term control.     

Malignant histiocytosis in a domestic cat: cytomorphologic and immunohistochemical features

Malignant histiocytosis (MH) was diagnosed in a 13-year-old neutered male Domestic Shorthair cat on the basis of light microscopic and immunohistochemical findings. Thoracic fluid analysis showed a modified transudate which contained a very few atypical discrete cells. Cytologic and histologic evaluation of mediastinal and splenic masses revealed a pleomorphic population of large, discrete, round cells 10 to 30 micrometers in diameter with marked cellular atypia. Nuclei were oval to reniform, often with prominent, bizarre nucleoli. Multinucleated cells and mitotic figures were commonly seen. Erythro- and leucocytophagia were noted. Immunohistochemistry indicated a scattered positive staining pattern with the histiocytic antigenic marker Mac387 and a minor population of cells showing positive reactivity for lysozyme. This report describes the characterization of MH in a cat and emphasizes that MH should be considered as a differential diagnosis in proliferative disorders of discrete-cells in this species.     

Liposomal clodronate treatment for tumour macrophage depletion in dogs with soft‐tissue sarcoma

Increased numbers of tumour‐associated macrophages correlate with rapid tumour growth and metastasis in tumours. Thus, macrophage depletion has potential as a novel cancer therapy and positive responses have been reported in rodent tumour models. To investigate the effectiveness of this approach in dogs with cancer, we evaluated the effects of the macrophage‐depleting agent liposomal clodronate (LC) in dogs with soft‐tissue sarcoma (STS). To this end, we conducted a clinical trial of LC therapy in 13 dogs with STS. Repeated LC administration was well tolerated clinically. Preliminary examination of tumour biopsy sets from 5 of the 13 dogs demonstrated that the density of CD11b⁺ macrophages was significantly decreased after LC treatment. Circulating concentrations of interleukin‐8 were also significantly reduced. These preliminary studies are the first to suggest that LC can be used as a systemic macrophage‐depleting agent in dogs to reduce numbers of tumour‐associated macrophages.     

A dose‐finding study with a novel water‐soluble formulation of paclitaxel for the treatment of malignant high‐grade solid tumours in dogs

A new formulation of water‐soluble paclitaxel (Paccal® Vet) has been developed for canine cancer patients, without the need for pre‐medication (traditionally required in non‐water‐soluble paclitaxel formulations). The objective of the study was to determine a clinically safe and efficacious dose of Paccal Vet and to estimate progression‐free and overall survival and to evaluate single‐dose pharmacokinetics in tumour‐bearing dogs. A positive risk:benefit ratio was established for Paccal Vet administered at 150 mg m^–2 intravenous (IV) for three or more treatment cycles. Preliminary efficacy was demonstrated by best objective response rate (86%), median time to response (14 days) and median progression‐free survival (131 days). Paccal Vet was associated with expected adverse events (AE) (e.g. myelosuppression), however the majority were transient, clinically silent and manageable. This is the first clinical report of a water‐soluble formulation of paclitaxel suggesting successful administration and being safely used without pre‐medication in dogs.     

Reference intervals for transthoracic echocardiography in the American Staffordshire Terrier

This study reports the echocardiographic reference intervals in the American Staffordshire Terrier (AST). The echocardiographic variables obtained in 57 healthy adult AST were compared with published data from the general canine population and other breeds. In the AST, the left ventricular volumes were lower than values reported in Boxers and Dobermans (P<0.0001), but higher than in small breeds (P<0.0001). The left ventricular ejection fraction was higher than Boxers and Dobermans (P<0.0001), but lower than small breed dogs (P=0.027). The aortic peak velocity values were similar to Boxers (P=0.55) but higher than the general canine population (P<0.0001). The reference intervals presented in this study are clinically useful for an accurate echocardiographic interpretation and screening in the AST.     

Malignant teratoid medulloepithelioma with brain and kidney involvement in a dog

ANIMAL STUDIED: A tumor of the left eye with involvement of the brain and kidney was diagnosed in a 4-year-old Neapolitan mastiff. PROCEDURE: The dog presented with acute glaucoma of the left eye. Peripheral corneal vascularization and severe corneal edema obscured examination of deeper structures. Because of concurrent progressive neurologic signs the dog was euthanized and a postmortem examination was performed. The eyes, brain and samples from the lung, heart, liver and kidneys were fixed in 4% neutral buffered formalin and embedded in paraffin wax. Sections were examined by light microscopy including histochemical and immunohistochemical staining. RESULTS: The ocular tumor originated from the ciliary body and was composed of small islets and cords of poorly differentiated, oval to polyhedral cells surrounded by abundant ground substance. Areas with chondroid differentiation were observed. Rosettes were not found. Metastases with the same morphology were present in the brain and in one kidney. CONCLUSION: An intraocular malignant teratoid medulloepithelioma with metastases to the brain and kidney is presented.     

Effects of low‐dose cyclophosphamide with piroxicam on tumour neovascularization in a canine oral malignant melanoma‐xenografted mouse model

Low‐dose cyclophosphamide (CyLD) has shown promise in the treatment of several cancers; however, the effect of CyLD on canine oral malignant melanoma has never been explored. In this study, we investigated the effects of CyLD with or without piroxicam (Px) on tumour neovascularization and vascular normalization in a canine oral malignant melanoma‐xenografted mice model. After treatment with CyLD, Px or a combination of both (CyPx), the growth of the tumour in the treatment groups was significantly suppressed compared to the control group at 30 days of treatment. Proliferation index was also significantly reduced by all treatments, only CyPx significantly lowered microvessel density and vascular endothelial growth factor (VEGF) levels. Additionally, CyLD significantly reduced the proportion of normal vessels and caused an imbalance between VEGF and thrombospondin‐1. These results suggested that CyPx has potent anti‐angiogenic effects in terms of both the number and quality of blood vessels in xenografted canine oral malignant melanoma.     

Spontaneous Malignant T Cell Lymphoma in a Young Male Common Marmoset (Callithrix jacchus)

We histopathologically and immunohistochemically investigated a case of malignant lymphoma that spontaneously developed in a male common marmoset at two years of age. Beginning at two years four months of age, the animal had an enlargement of the submandibular and inguinal lymph nodes, small subcutaneous nodules near the right breast and an approximately fivefold increase in peripheral lymphocyte count compared with the previous examination value. The postmortem findings at two years eight months of age showed lymphadenopathy with enlargement of the thymus and spleen. Small- to intermediate-sized neoplastic lymphocytes had diffusely proliferated in the enlarged nodes. The neoplastic cells were pleomorphic and had irregularly shaped nuclei. The nuclear chromatin staining revealed hyperchromatism in the small-sized cells, and the intermediate-sized cells exhibited vesicular staining. An immunohistochemical examination indicated that the neoplastic lymphocytes were positive for CD3 and negative for CD20, thus suggesting that they had originated from T cells. In addition, the proliferation of high endothelial venules and reactive epithelioid histiocytes was observed. Scattered tingible body-laden macrophages were infrequently detected. Neoplastic lymphocytes were also observed in the thymus, spleen, heart, lungs, liver, kidneys, adrenal glands and femoral and sternal bone marrow. This malignant lymphoma in a young male common marmoset was considered to fit the category of “peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS)” according to the new WHO system of classification.     

Large anaplastic spinal B‐cell lymphoma in a cat

Abstract: A 5‐year‐old female spayed domestic shorthair cat was presented for evaluation of tetraparesis. The neurologic lesion was localized to the cervical spinal segment (C1–C6). A left axillary mass was identified, and the results of fine needle aspiration cytology indicated malignant round cell neoplasia of possible histiocytic origin. The cells were large, had marked anisocytosis and anisokaryosis, occasional bi‐ and multinucleation, and cytoplasmic vacuolation. Euthanasia was performed due to the poor prognosis associated with severe, progressive neurologic signs and a malignant neoplasm. Postmortem examination revealed spinal cord compression and an extradural mass at the C1–C2 spinal segment, with neoplastic cells in the adjacent vertebral bodies, surrounding skeletal muscle, left axillary lymph node, and bone marrow from the right femur. The initial histologic diagnosis was anaplastic sarcoma, but immunohistochemical results indicated the cells were CD20+ and CD45R+ and CD3?, compatible with a diagnosis of B‐cell lymphoma. CD79a staining was nonspecific and uninterpretable. Weak to moderate CD18 positivity and E‐cadherin positivity were also observed. Clonality of the B‐cell population could not be demonstrated using PCR testing for antigen receptor gene rearrangement. To the authors' knowledge, this is the first reported case of a feline spinal anaplastic B‐cell lymphoma exhibiting bi‐ and multinucleated cells. The prognostic significance of this cell morphology and immunophenotype is unknown.     

Uveal schwannoma in a brown‐eyed dog

An eleven‐year‐old, female spayed Boxer dog was diagnosed with a uveal schwannoma (formerly known as the spindle cell tumor of the blue‐eyed dog or SCTBED) despite having a uniformly brown iris. The patient presented to emergency for ocular discomfort, and the right globe was subsequently enucleated due to glaucoma and submitted for histopathology. Upon histopathologic evaluation, a uveal schwannoma was diagnosed and confirmed with immunohistochemical staining. Complete metastatic evaluation 1 and 6 months after initial presentation did not reveal evidence of metastasis, and the dog remains systemically healthy. This case represents a unique variant of uveal schwannoma and is relevant because although the vast majority of these tumors occur in blue‐eyed dogs, clinicians should not completely rule out this tumor as a differential based on the iris color.     

Concurrent multiple myeloma and mast cell neoplasia in a 13‐year‐old castrated male Maine Coon cat

A 13‐year‐old, castrated male Maine Coon cat was presented to Oklahoma State University Boren Veterinary Medical Teaching Hospital for yearly echocardiographic examination monitoring hypertrophic cardiomyopathy (HCM) diagnosed in 2003. Physical examination revealed a heart murmur and premature beats, likely related to HCM, but was otherwise unremarkable. A biochemistry profile revealed a hyperglobulinemia (6.3 g/dL). Cytologic examination of fine‐needle aspirates from liver and spleen revealed increased numbers of plasma cells and mast cells, confirmed with subsequent histologic examination. Immunohistochemistry (IHC) for c‐kit in the spleen and liver showed mast cells predominantly exhibiting type I staining pattern, with moderate numbers exhibiting type II pattern in spleen, and scattered cells exhibiting type II and III patterns in liver. Bone marrow cytology and core biopsy documented approximately 22% plasma cells. Cutaneous masses on the cat's left shoulder and right carpus were cytologically confirmed mast cell tumors. Serum protein electrophoresis with immunofixation confirmed an IgG monoclonal gammopathy. This is an example of 2 hematologic neoplasms occurring simultaneously in a cat. Concurrent pathologies may be overlooked if a single disease is diagnosed and suspected of causing all clinical signs. Both neoplasms were well differentiated, and neoplastic cells could have easily been interpreted as a reactive population had a full workup not been performed. Missing either diagnosis could result in a potentially lethal outcome. Eleven months after diagnoses, the cat was clinically doing well following a splenectomy and oral prednisolone and chlorambucil chemotherapy. Globulins decreased to 4.9 g/dL.     

Treatment of canine oral papillary squamous cell carcinoma using definitive‐intent radiation as a monotherapy—a case series

Canine oral papillary squamous cell carcinoma (COPSCC) is a rare neoplasm and although locally invasive it carries a favourable prognosis following wide surgical excision. Radiotherapy has been reported to be effective as an adjunct treatment to surgery. However, limited information is available on the role of radiotherapy as single treatment. This single‐institution retrospective study describes a series of 10 dogs diagnosed with macroscopic COPSCC that were treated with definitive‐intent radiotherapy (DRT) as a monotherapy. These dogs had a median age of 4 years (range: 0.4‐9.6 years). The tumour was located in the rostral oral cavity in all cases with a median tumour size of 2.5 cm (range: 0.8‐6.8 cm). No local or distant metastases were identified. All dogs were treated with electron beam DRT (>32Gy, 10‐16 daily fractions of 3.2Gy). The median follow‐up time was 961 days (range: 333‐3.498 days) with nine dogs achieving a complete response and one dog a partial response. The dog with the partial response developed disease progression at 228 days after initiation of radiotherapy. Two dogs died from non‐tumour‐related causes. The remaining seven dogs were still alive and in complete remission at the time of last follow‐up. Median progression‐free survival time and median survival time were not reached. DRT was generally well tolerated, but all dogs experienced self‐limiting acute radiation mucositis (grade 2‐3) and/or dermatitis (grade 1). No late radiation toxicity was observed. Macroscopic COPSCC appears to be a radiosensitive tumour that can be successfully treated with DRT eliminating the need for aggressive surgery in advanced cases.     

Diet‐associated hepatic failure and immune‐mediated hemolytic anemia in a Weimaraner

Objective: To describe the medical and nutritional management of a 4‐year‐old Weimaraner with acute hepatic failure and immune‐mediated hemolytic anemia (IMHA) associated with consuming a commercial dog food. Case summary: A 4‐year‐old male castrated Weimaraner developed signs of IMHA, hepatic failure, disseminated intravascular coagulopathy, and malnutrition after consuming a commercial dog food. During the course of hospitalization, medical management included immunosuppressive therapy and supportive care. Nutritional support consisted of both enteral and parenteral nutrition. The dog was discharged after 19 days of hospitalization and fully recovered by 6 months. An investigation by the Food and Drug Administration was not able to determine the exact cause of the acute hepatic failure and IMHA. New information provided: This is the first case report documenting the medical and nutritional management of a critically ill animal associated with ingestion of this commercial dog food.     

Budd–Chiari-like syndrome in a dog with a chondrosarcoma of the thoracic wall

Objective: To describe a dog with Budd–Chiari‐like syndrome secondary to caudal vena cava compression from a thoracic wall chondrosarcoma. Case summary: A 9‐year‐old spayed female Shetland Sheepdog cross with a recent history of non‐productive cough developed severe abdominal distension and dyspnea. Marked ascites and enlarged hepatic veins were identified with ultrasonography. At surgery, a right thoracic wall mass was found to be compressing the caudal vena cava. Fluid analysis of the ascites revealed a modified transudate with elevated protein concentration, consistent with Budd–Chiari‐like syndrome. Clinical signs resolved following thoracotomy and complete resection of the mass. New or unique information provided: Obstruction of venous blood flow can result from compression exerted by a space‐occupying thoracic wall mass on the caudal vena cava. Clinical resolution can be achieved with return of adequate venous circulation by removal of the mass and alleviation of the external pressure.     

Non‐immunosuppressive FTY720‐derivative OSU‐2S mediates reactive oxygen species‐mediated cytotoxicity in canine B‐cell lymphoma

OSU‐2S is a FTY720 (Fingolimod) derivative that lacks immunosuppressive properties but exhibits strong anti‐tumour activity in several haematological and solid tumour models. We have recently shown OSU‐2S to mediate potent cytotoxicity in human mantle cell lymphoma cell lines and primary cells. We report here the pre‐clinical activity of OSU‐2S in spontaneous B‐cell lymphoma of dogs which shares many characteristics of human lymphoma. OSU‐2S mediated apoptosis in canine B‐cell lines and primary B‐cell lymphoma cells obtained from spontaneous lymphoma bearing dogs. OSU‐2S induced reactive oxygen species (ROS) in canine lymphoma cells and inhibition of ROS partially rescued OSU‐2S‐mediated cell death. These studies provide a rational basis for the use of spontaneous lymphoma in pet dogs as a preclinical large animal model for the development of OSU‐2S as small molecule for treating people and dogs with lymphoma.