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.     

Spinal epidural empyema concurrent with sequestrum in a cat: a case report

A 5-month-old intact female mixed cat presented with repetitive paraplegia and drainage of pus from the back despite continuous antibiotic medication. Neurologic examination was consistent with below T3-L3 myelopathy. Computed tomography and magnetic resonance imaging revealed a contrast-enhanced mass in the L1-3 spinal canal, and bone fragments in the T13 and L1 spinal canal. Spinal epidural empyema was suspected, and hemilaminectomy was performed for T12-L2 on the right side and T11-12 on the left side. Bone fragments were diagnosed as sequestrum infected with Bacteroides sp. The cat recovered enough to ambulate next day. One month after surgery, there was no deficit in neurological function. This is the first report of spinal epidural empyema concurrent with sequestrum in a cat.     

Carcinocythemia: First report in a cat and literature review

A 6‐year‐old female neutered European Shorthair cat was presented with a 2‐day history of lethargy and hyporexia. On physical examination, the cat was slightly depressed and had a 2.5 cm nodule in the left 3^rd mammary gland. The hemogram revealed mild leukocytosis with mature neutrophilia and moderate thrombocytopenia. On blood smear evaluation, rare pleomorphic cells, possibly of epithelial origin, were observed mainly at the feathered edge. The animal died about 12 hours after presentation, and a necropsy was performed. On histopathology, the mammary nodule was diagnosed as a tubulopapillary adenocarcinoma with vascular invasion and widespread metastases. Immunocytochemical tests for cytokeratins (AE1/AE3) confirmed the epithelial phenotype of the neoplastic cells observed on the blood smear. The present report describes a feline mammary carcinoma with widespread metastases and the presence of malignant epithelial cells in the peripheral blood referred to as carcinocythemia. This condition has been previously described in people and dogs. To the author's knowledge, this is the first reported case of feline carcinocythemia. As in other species, the phenomenon was associated with a terminal phase of systemic malignancy.     

Canine ocular onchocerciasis in the United States: two new cases and a review of the literature

Since 1991, 53 cases of canine ocular onchocerciasis have been reported in the literature worldwide, 43 of these were from Greece, five from Hungary, and five from the western United States. Information on the histopathologic features of canine ocular onchocerciasis is limited. We describe the histopathologic features of canine ocular onchocerciasis in two dogs from California that presented clinically with firm episcleral nodules and uveitis unilaterally. Pertinent literature and pathogenesis are reviewed; recognizable clinical features and treatment are discussed. The cases presented were diagnosed via histopathology of the enucleated globes and episcleral granulomas at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Positive identification of adult Onchocerca within episcleral granulomas was made based on light-microscopy features. Histopathologic examination of both globes revealed episcleral parasites surrounded by granulomas containing few to moderate numbers of eosinophils. Other sequelae, in both cases, included lymphoplasmacytic uveitis, preiridal fibrovascular membranes, peripheral anterior synechiae, retinal degeneration, and optic nerve head cupping. Both male and female worms were present, as were in utero microfilariae in both cases. Worms in both cases were tentatively identified as Onchocerca lienalis. Ocular onchocerciasis should be a differential consideration in cases of canine conjunctival nodules or periorbital swelling, particularly in dogs from the western United States.     

Intestinal ganglioneuroma in a kitten–a case report and review of literature

An intestinal ganglioneuroma of a 6–week–old male kitten is described. The neoplasm was well circumscribed and involved a 6–5–cm segment of the jejunum, which was dilated and had a 6–10 mm thick wall. It was characterized histologically by irregularly–arranged bundles of nerve fibres, with Schwann cells and single or groups of round or angular ganglion cells. Some of the ganglion cells had satellite cells. Vessels with prominent endothelial cells, and islands of epithelial cells forming acini, were also seen. The age of the kitten and slow nature of growth of this tumour led the authors to believe that this is a case of congenital neoplasia. This is the first report of an intestinal ganglioneuroma in a cat.     

Cyclic hematopoiesis in a mixed-breed dog: case report and brief review

An 8-wk-old, male, mixed-breed puppy was adopted from a rescue organization. From the time of adoption, the puppy suffered episodes of illness affecting various organ systems, which resolved with supportive therapy but relapsed once medical therapy was discontinued. Review of the hematologic data revealed cyclic fluctuations in circulating blood cells. Cyclicity was most prominent in neutrophils, with recurrent severe neutropenia. Neutropenic episodes lasted 5–6 d, with regular cycles of 11–14 d between nadir neutrophil counts. Genetic testing determined that the patient was homozygous mutant for the frameshift mutation in the adaptor protein complex 3 β-subunit (AP3B1) gene, originally identified in gray collies with cyclic hematopoiesis (CH). Pedigree information was not available, but the patient’s features were phenotypically distinct from those of collies. We describe here a case of the AP3B1 mutation in a mixed-breed dog that did not resemble a collie, undescribed previously, to our knowledge. Our findings indicate that the AP3B1 mutation and CH are present within the general canine population and are not restricted to collies.     

Olfactory ganglioneuroblastoma in a dog: case report and literature review

A 7-y-old, intact male Alaskan Malamute was presented with a 3-mo history of stertor and epistaxis. Computed tomography of the skull revealed generalized loss of gas throughout both nasal passages with replacement by a soft tissue mass that traversed the cribriform plate. Histopathology revealed neoplastic neuroblast cells arranged in anastomosing cords, as well as separately located aggregates of ganglion cells. Both neoplastic cell populations demonstrated immunoreactivity to MAP-2, TuJ-1, and synaptophysin. Neuroblastic cells additionally exhibited punctate immunoreactivity to MCK and CK8/18. We document here both the positive neural immunohistochemical markers for this neoplasm, as well as propose possible histomorphologic variants.     

Everted third eyelid cartilage in a cat: a case report and literature review

An 8-year-old neutered female British Blue cat was presented with a presumed diagnosis of a prolapsed nictitans gland and associated ocular irritation and epiphora. However, during surgery, the apparent nictitans gland protrusion was determined to be an everted cartilage of the nictitating membrane. The scrolled portion of the cartilage was removed through an incision through the conjunctiva on the bulbar aspect of the third eyelid, as previously described in the dog. This operation resolved the ocular irritation occurring, and the third eyelid returned to its anatomically correct position.     

Cutaneous leiomyosarcoma with visceral metastases in a White Carneau pigeon and literature review

Cutaneous leiomyosarcomas are malignant mesenchymal tumors of smooth muscle origin and are reported occasionally in avian species. A 14-y-old male laboratory White Carneau pigeon (Columba livia) was presented for surgical excision of a cervical soft tissue mass. Ultrasonography with color flow Doppler imaging revealed multiple cavitations of mixed echogenicity within the mass and vascularization. Histologically, the dermis and subcutis were expanded by a densely cellular multinodular mass comprised of fusiform cells forming haphazardly arranged broad streams and short interwoven bundles, often surrounding blood vessels and variably sized cavitations. Neoplastic cells were strongly immunopositive for desmin and α–smooth muscle actin, and negative for pancytokeratin, S100, and von Willebrand factor. Based on histopathology and IHC findings, the cutaneous mass was diagnosed as leiomyosarcoma (LMS). The pigeon died 312 d post-operatively. Postmortem examination revealed masses infiltrating the left and right pulmonary airways and one hepatic nodule, but no regrowth at the surgical site. Histologic and IHC evaluation of the pulmonary and hepatic masses were consistent with LMS, representing metastatic foci from the primary cutaneous LMS. Our case highlights the malignant behavior and histomorphologic features of cutaneous LMS in an avian species.     

Chalastospora gossypii in a Maine Coon cat: case report and literature review

A 15-y-old castrated male Maine Coon cat was evaluated for an ulcerated soft tissue mass on the right hindlimb that had been observed for 4 mo and had grown rapidly. A 3 × 3 cm soft, raised, amorphous, and ulcerated subcutaneous mass was observed on the lateral right metatarsus. In-house cytology via fine-needle aspiration was nondiagnostic. Incisional biopsy of the mass and further staging was declined, and amputation was elected. The amputated limb was submitted for histopathology, which revealed severe chronic nodular granulomatous dermatitis and multifocal granulomatous popliteal lymphadenitis with large numbers of intralesional fungal hyphae. Fungal PCR and sequencing on formalin-fixed, paraffin-embedded tissue identified Chalastospora gossypii. No adjunctive therapy was elected at the time. The patient has done well clinically 1 y post-operatively. C. gossypii is a rare microfungus found worldwide and is considered a minor pathogen of several plants. To our knowledge, infection by this fungus has not been reported previously in veterinary species. Features in our case are comparable to other mycotic infections. Nodular granulomatous mycotic dermatitis and cellulitis, although uncommon, should be a differential for soft tissue masses in veterinary species; C. gossypii is a novel isolate.     

Rickets in a Thoroughbred-cross foal: case report and review of the literature

Rickets is a metabolic bone disease associated with failure of endochondral ossification and impaired osteoid mineralization in growing animals. As a consequence, affected individuals can develop gross and microscopic bone malformations. The most common causes of rickets in domestic species include vitamin D and phosphorus deficiency. Rickets has been described in multiple species; however, comprehensive postmortem characterizations with confirmatory histopathology in equids have not been published. A 6-mo-old, Thoroughbred-cross foal was diagnosed with rickets based on gross autopsy findings and microscopic examination of the ribs and long bones. Grossly, all costochondral junctions of the ribs were enlarged with a “rachitic rosary” appearance, and there were multiple fracture calluses in the rib bodies. Epiphyses and metaphyses of the long bones appeared widened on sagittal section, and their physes were irregularly thickened. Histologically, there were poorly organized columns of hypertrophic chondrocytes within the physes of affected bones, islands of chondrocytes embedded within the primary and secondary spongiosa, and faintly eosinophilic seams of poorly mineralized osteoid within the bone trabeculae. Areas of focally increased osteoclastic activity were observed in some of the sections, perhaps pointing to a more complex metabolic bone disease in a growing animal. Low serum concentrations of calcium and 25-hydroxyvitamin D were detected in an antemortem sample. The pathogenesis of these imbalances was not definitively established, but lack of sunlight exposure, low concentration of vitamin D precursors in the diet (perhaps secondary to malnutrition), or both, were suspected; a genetic basis cannot be ruled out.     

Synovial fluid eosinophilia: a case report in a dog and review of the literature

The first known report of synovial fluid eosinophilia in a dog is described here. The occurrence of eosinophils in joint fluid is rare. Sporadic cases have been recorded in humans and most can be related to immunemediated reactions, both parasitic and non- parasitic. The dog in this case report had 20-52% eosinophils in multiple joints, as well as hemarthrosis and marked mononuclear cell reactivity. An intense peripheral eosinophilia was demonstrated one week later. The associated lameness resolved with non-steroidal anti-inflammatory therapy. Lack of remarkable history or other clinical symptoms led to a diagnosis of idiopathic, eosinophilic, polyarthritis, likely immune-mediated.     

Meningoencephalomyelitis in domestic cats: 3 cases of Pasteurella multocida infection and literature review

Neurologic diseases are common in domestic cats, and infectious agents are suspected to be the primary cause in 30–45% of cases. Among infectious etiologies, those of bacterial origin are only sporadically characterized in the literature, with few of these reports correlating gross and histologic findings with confirmatory bacteriologic identification. Here, we describe bacterial meningitis and meningoencephalomyelitis associated with Pasteurella multocida in 3 domestic cats. Purulent exudate expanding the cerebral meninges was grossly evident in 2 of the cases. In all 3 cases, histologic changes included multifocal suppurative-to-necrosuppurative meningitis and/or meningoencephalomyelitis of variable severity. Intralesional colonies of gram-negative, short rod-shaped to coccobacillary bacteria were evident histologically in only 1 case. P. multocida was confirmed by routine bacteriologic culture in all cases. Based on our cases, we hypothesize that the upper respiratory system serves as the main portal of entry for P. multocida, leading to invasion of the central nervous system and possible systemic hematogenous dissemination. A case series of meningoencephalomyelitis associated with P. multocida infection in cats has not been reported previously, to our knowledge. We also review briefly other causes of meningoencephalomyelitis in cats.     

Granular variant of a histiocytic tumor on the toe of a cat: Case report and literature review

A 16-year-old female spayed domestic shorthaired cat was examined for lameness and a mass on the fourth digit of the right hindlimb. Cytologic examination of an aspirate of the mass revealed large discrete cells admixed with low numbers of well-granulated mast cells. The discrete cells contained single to many variably sized light pink to purple granules in their cytoplasm and had pleomorphic nuclei, with intranuclear cytoplasmic inclusions. Karyomegalic, binucleated and multinucleated cells were seen. Histologic examination of formalin-fixed sections of the excised mass showed a mildly infiltrative, unencapsulated, multinodular dermal mass that extended into the subcutis and consisted of similar discrete cells. On immunohistochemical staining, the tumor cells expressed ionized calcium-binding adapter molecule 1 (Iba1) and CD18. The tumor cells did not express CD3, CD20, CD117, pancytokeratin (AE1/AE3), melanoma antigen (Melan-A), multiple myeloma oncogene-1 (MUM1), melanoma-associated antigen (PNL-2), and S-100. Low numbers of tumor cells expressed CD204 and protein gene product 9.5 (PGP9.5). Granules were variably positive for Periodic-acid Schiff (PAS) and Alcian blue. On transmission electron microscopy, the cells contained filopodia, abundant endoplasmic reticulum, and moderate numbers of low-density membrane-bound granules. This case documents a previously undescribed granular variant of a histiocytic tumor in a cat.     

Malignant thymoma with widespread metastases in a dog: case report and brief literature review

A malignant thymoma of epithelial type with metastases to the liver, spleen and bone marrow in a 16 year old female Cocker Spaniel dog is described. Lesions were considered to be incidental findings at necropsy.     

Ectopic brain tissue in the retina of a beagle dog: a case report and literature review

Isolated ectopic brain tissue within the orbit is an extremely rare finding and has never been reported in dogs or other domestic species. In this case, a focal choristoma of ectopic grey matter-like tissue was present within the retina of a mature female beagle dog, and consisted of neurons and astrocytes as demonstrated respectively by microtubule-associated protein 2 and glial fibrillary acidic protein immunohistochemistry. The lesion was located within the optic fundus adjacent to the optic disk and surrounded by dysplastic retina. The case is presented with a review of literature on this rare entity.