Pulmonary adenosquamous carcinoma in a dog

A mass that developed in the lung of a 10-year-old mixed-breed dog was pathologically examined. Histopathological examination showed papillary and tubular growth of glandular epithelium-like cells in some areas and growth of squamous cells arranged in nests in other areas, showing coexistence of adenocarcinoma and squamous cell carcinoma in a lung tumour. Immunohistochemical staining with anti-keratin-cytokeratin antibody was strongly positive for cytoplasms in both components. Electron microscopically, the neoplastic cells of the adenocarcinoma component had features of glandular cells, with microvilli, numerous free ribosomes, large round secretory granules and intercellular desmosomes. Non-keratinized squamous cells had tonofilaments and intercellular desmosomes. These findings led to the diagnosis of primary adenosquamous carcinoma, which demonstrates phenotypic profiles characteristic of both epidermal keratinocytes and glandular epithelium.     

Calvaria and orbital metastases of pulmonary adenosquamous carcinoma in a cat: a diagnostic challenge

An 11-year-old cat with a 4-month history of lethargy, inappetence, dysphagia, partial mandibular paralysis and weight loss, was euthanized due to the rapid deterioration of his condition. Post-mortem radiographic examination revealed severe bone lysis of the left zygomatic arch, temporal and parietal bones. Magnetic resonance imaging of the head showed a large isointense mass of the left side of the skull associated with extensive lysis of the parietal and temporal bones and destruction of the adjacent tympanic bulla. Gross and histological examinations revealed a pulmonary adenosquamous carcinoma of the left lung, with metastases to the spleen, liver, mesenteric lymph nodes, mesentery, diaphragm, abdominal aorta, left orbit and calvaria. No limb or digit metastases were detected.     

Hypertrophic osteopathy associated with pulmonary adenosquamous carcinoma in a dog

A six-year-old intact female Maltese dog weighing 3.8 kg presented with a history of mild lameness and swelling on both forelimbs. Radiographic and computed tomographic views revealed an extensive periosteal reaction in all four limbs and a large round mass on the right middle lung lobe. A total lobectomy was performed and pulmonary adenosquamous carcinoma was histologically confirmed. A diagnosis of hypertrophic osteopathy (HO) secondary to a lung tumor was made. Periosteal proliferation decreased significantly after surgery; however, there was evidence of dyspnea, mass recurrence, and periosteal reaction three months post-operatively. This is the first case report of pulmonary adenosquamous carcinoma with HO in a dog in which we describe clinical, imaging, surgical, and histological findings.     

Laryngeal carcinoma in a cat

Laryngeal neoplasia was diagnosed in a 5-year-old domestic shorthair cat examined for cough and gagging episodes. Resection of the mass revealed a squamous carcinoma which had invaded the deep floor of the larynx. Primary neoplasia of the feline larynx is a rare condition but needs to be distinguished from other obstructive laryngeal conditions, using radiography, laryngoscopy and biopsy.     

Anal sac gland carcinoma in a cat

A perianal mass in a 15-year-old domestic shorthair cat with a history of a firm, painful swelling in the left ventrolateral perianal region was surgically excised and submitted for light microscopic evaluation. Histologically, this was a poorly demarcated, unencapsulated, multilobulated neoplasm that invaded surrounding perirectal skeletal muscle bundles. Lobules were composed of sheets and acinar arrangements of cuboidal to round neoplastic epithelial cells with scant to moderate eosinophilic to amphophilic cytoplasm and a round or oval nucleus with coarse chromatin. Mitotic figures were 2 per 40 x objective field. Acinar lumina sometimes contained eosinophilic proteinaceous material or cell debris. These microscopic features are consistent with anal sac gland carcinoma. This is the second report of this neoplasm in a cat.     

Nasal acinic cell carcinoma in a cat

This case report describes the clinical, magnetic resonance imaging (MRI)-related, and pathologic features of a nasal acinic cell carcinoma in a cat. A 16-year-old, castrated male, oriental shorthaired cat, weighing 3.8 kg, was presented with history of sneezing, coughing, and nasal discharge persisting several months. Evaluation by MRI revealed an heterogeneous, space-occupying lesion that filled the left nasal cavity and was diagnosed by histopathologic examination as an acinic cell carcinoma arising from a minor salivary gland of the nasal cavity. Acinic cell carcinoma is a rare tumor in veterinary medicine. The tumor is composed mainly of cells resembling serous cells of salivary glands and originates from major or minor salivary glands. Clinicians and pathologists should be aware of the occurrence of acinic cell carcinoma in the sinonasal tract and include the tumor in the differential diagnosis of feline nasal diseases.     

Urethral transitional cell carcinoma in a cat

A 15-year-old, male neutered cat was referred for investigation of dysuria. A retrograde urethrography was performed which showed two space-occupying masses within the lumen of the mid-to-proximal urethra. Exploratory coeliotomy revealed two urethral masses. Segmental urethrectomy was performed to resect the mass, and the lower urinary tract was reconstructed by vesico-urethral anastomosis. Histopathology showed the mass to be a transitional cell carcinoma with incomplete surgical margins. Tumour regrowth was suspected when dysuria was found approximately 318 days after surgery. Clinical signs were palliated by radiation using weekly fractions of 6 Gy for three weeks. The cat died of unknown causes 386 days postoperatively.     

Hepatocellular carcinoma with secondary abscessation in a cat

A 16-year-old castrated male domestic shorthair cat was presented for investigation of weight loss, lethargy, inappetence and polydypsia. On serum biochemical analysis there was evidence of severe hepatocellular damage and cholestasis. Abdominal ultrasonographic examination revealed an irregular lesion of mixed echogenicity in a left hepatic lobe. It was compromised of a hypoechoic periphery surrounding an anechoic central area containing highly echogenic densities with distal acoustic shadowing suggestive of gas formation. On necropsy, the only gross abnormality was a solitary 5 cm x 3 cm x 3 cm multilobulated mass in the left lateral hepatic lobe, containing foul-smelling purulent fluid within a thick fibrous wall. Cytological examination of the fluid revealed numerous degenerate neutrophils and large numbers of Gram-positive spore-forming rods. The histopathological diagnosis was hepatocellular carcinoma with secondary abscessation. The bacterial morphology was consistent with Clostridia sp. Both hepatocellular carcinoma and focal hepatic abscessation are rare in cats. Hepatic abscesses should be included in the differential diagnosis of cats with non-specific signs, even in the absence of biochemical evidence of a hepatopathy.     

Transitional cell carcinoma forming a perirenal cyst in a cat

An eight-year-old, neutered male Burmese cat presented with five days vomiting and anorexia. Physical examination, clinical pathology and diagnostic imaging findings suggested a perirenal pseudocyst. After partial resection of the perirenal capsule clinical signs temporarily resolved, but the cat was euthanased 34 days postoperatively as a result of seizures and recurrence of vomiting. Postoperative histopathology showed neoplastic transitional cells within and lining the resected perirenal capsule; a diagnosis of transitional cell carcinoma was confirmed post-mortem. To the authors' knowledge, this is the first report of this presentation of transitional cell carcinoma. Transitional cell carcinoma should be a differential diagnosis for the aetiology of perirenal pseudocyst.     

Lipid-rich carcinoma of the mammary gland in a cat

A 1.5-year-old female, intact, clinically healthy cat presented for a subcutaneous mass of the ventral abdomen. Surgical excision and microscopic examination of the mass were performed. Histologically, this was a discrete, unencapsulated, multilobular, expansile mass, which compressed the surrounding normal mammary tissue. Lobules were composed of tubuloacinar structures formed by atypical round to polygonal cells, which contained foamy to microvacuolated cytoplasm and variably sized, intracytoplasmic, distinct vacuoles causing nuclear peripheralization. Neoplastic cells demonstrated intense and diffuse immunoreactivity for cytokeratin and lacked immunoreactivity for vimentin. The vacuolar contents stained positively with Oil RedO and negatively with periodic acid-Schiff and Alcian blue stains. Histomorphologic, histochemical, and immunohistochemial analysis support a diagnosis of lipid-rich mammary carcinoma. This is the first report of a cat with a lipid-rich variant of mammary carcinoma.