What is your diagnosis? Ventral neck mass in a dog

Abstract: A 14‐year‐old male Labrador Retriever was presented for lethargy and collapse. On physical examination, numerous abnormalities were found, including a large ventral neck mass (100 cm³) in the area of the thyroid gland. Fine‐needle aspirates revealed 2 apparent populations of cells: one suspected to be a well‐differentiated thyroid carcinoma, and the other consisting of large pleomorphic to spindloid cells suggestive of sarcoma. Two days later, the dog died at home. A full necropsy was not performed, but examination of the head and neck revealed a well‐encapsulated mass adjacent to the cranial trachea and larynx. A section of the mass was evaluated histologically and a diagnosis of anaplastic thyroid carcinoma was made. Immunohistochemical evaluation with antibodies to thyroglobulin, cytokeratin, and vimentin confirmed distinct populations of malignant epithelial and malignant mesenchymal cells, and the diagnosis was amended to thyroid carcinosarcoma. Thyroid carcinosarcoma is a rare neoplasm in dogs in which the cell type comprising the mesenchymal component can vary. Immunochemistry to demonstrate the 2 cell types may be necessary to differentiate thyroid carcinosarcoma from anaplastic thyroid carcinoma.     

Biliary cystadenoma in a Maltese dog: clinical and diagnostic findings

A 14-year-old Maltese dog presented for complete medical examination due to intermittent vomiting and diarrhea observed during the previous two days. A single, solitary, lobulated cystic mass was observed in the liver upon ultrasonographic and computed tomographic examination. After surgical hepatic resection to remove the mass, histological examination revealed a multilocular cyst lined by cuboidal to columnar epithelial cells, which is consistent with biliary cystadenoma. Here, we report the clinical, clinicopathological, histopathological, and diagnostic imaging findings of biliary cystadenoma in a dog.     

Esophageal duplication cyst in a dog

A cranial cervical mass was surgically removed from a dog. On histologic examination, the mass was consistent with an esophageal duplication cyst, a condition rare in humans and not reported in the dog.     

Canine bicavitary carcinomatosis with transient needle tract metastasis diagnosed by multiplex immunocytochemistry

A 6‐year‐old, male castrated, mixed‐breed dog was referred to the James L. Voss Veterinary Teaching Hospital at Colorado State University for bicavitary effusion. On examination, the dog was tachycardic and tachypneic with bilaterally decreased lung sounds. Thoracic and abdominal ultrasonic examination revealed pleural and peritoneal effusions, which were aspirated and submitted for fluid analysis and cytology. Both cavity fluids were classified as exudates with a large population of vacuolated mononuclear cells. Multiplex immunocytochemistry (ICC) for cytokeratin and vimentin demonstrated exclusively cytokeratin expression, indicating these cells were of epithelial origin. A full diagnostic evaluation was performed, including CBC, clinical chemistry, a pet‐side test for heartworm disease, ehrlichiosis, Lyme disease, and anaplasmosis, imaging modalities of thorax, abdomen, and heart, urinalysis, and fine‐needle aspirations of spleen, liver, and popliteal lymph nodes. The dog was diagnosed with pleural and peritoneal carcinoma with presumed carcinomatosis. A single dose of intracavitary carboplatin was administered before discharge, and over a period of 2 weeks, 5 thoracocenteses were performed. A subcutaneous mass was noted at a thoracocentesis site one week after initial presentation. Cytology of the mass was consistent with carcinoma, and neoplastic seeding of the tumor cells from the thoracocentesis was suspected. The dog was euthanized 15 days after the first visit, and a necropsy was performed. Findings were consistent with carcinomatosis secondary to anaplastic pulmonary carcinoma with transient subcutaneous seeding of neoplastic cells during routine thoracocentesis. This case demonstrates the utility of multiplex ICC in the clinical setting.     

Metastatic thyroid solid-follicular carcinoma in the cervical portion of the spine of a dog

A metastatic thyroid solid-follicular carcinoma in the cervical portion of the spine was responsible for severe tetraparesis in a dog. Myelography revealed an extradural compressive lesion dorsal and to the right of the midline of C3. Histologic examination was used to diagnose the mass as a solid-follicular thyroid carcinoma. The primary tumor was not evident on cervical palpation or radiography. A dorsal laminectomy centered over C3 was performed, and all visible tumor was removed from the spine. The owner declined any further treatment for the dog.     

Orbital apex syndrome secondary to an orbital sarcoma in a dog

A 12-year-old castrated male cocker spaniel dog was presented with a 4-week history of left episcleral injection and pawing at the face. Clinical examination findings included left internal and external ophthalmoplegia, left dorsal strabismus, pain opening the mouth, and intermittent amaurosis. Imaging studies revealed a left orbital apex mass with adjacent sphenoid bone lysis and extension into the cranial cavity. A left exenteration was performed and histopathology confirmed an orbital soft tissue sarcoma.Key clinical message:This report describes an orbital tumor causing orbital apex syndrome. This condition should be differentiated from cavernous sinus syndrome as the latter does not course with optic neuropathy.     

Bronchogenic cyst in a German shepherd dog

Intermittent episodes of fever, severe dyspnoea and cyanosis were observed in a two-and-a-half-year-old male German shepherd dog. The clinical signs were of sudden onset but disappeared within eight hours, in five almost identical episodes over a period of 40 days. Radiological examination of the thorax revealed a large rounded area of radiolucency surrounded by a thin radiopaque structure. The lesion increased in volume between examinations, but otherwise remained similar in appearance. It could not be confirmed from the radiographs whether the structure was situated in lung tissue or mediastinum. Bronchoscopic examination revealed no abnormal findings and there was no bacterial growth from samples taken 30 days after the onset of symptoms. A large, vesicular structure, partly adherent to the mediastinum, was surgically removed from the left cranial lung lobe. The structure was 8 to 10 cm in diameter and partly filled with mucoid pink fluid. Histological examination revealed that the wall contained traces of bronchial epithelial cells. On bacteriological examination of the fluid, Gram-positive, mucus-forming bacteria were present. The definitive gross pathological and histopathological diagnosis was a bronchogenic cyst which had developed secondarily to bronchiectasis. Bronchitis and peribronchitis were also identified. The dog recovered well after surgery and, at the time of writing, was in active duty as a police dog, showing no signs of respiratory illness.     

Primary ureteral giant cell sarcoma in a Pomeranian

An 8-year-old male neutered Pomeranian dog was presented to the Veterinary Teaching Hospital at Oregon State University for surgical treatment of hydronephrosis of the left kidney and a left cranial abdominal mass. A primary ureteral mass was found during exploratory surgery, and the mass was resected and ureteral anastomosis was performed. Cytologic evaluation of the mass revealed 3 distinct cell populations, including a large number of multinucleated giant cells, a moderate number of thin spindle-shaped cells, and cohesive clusters of transitional epithelial cells. The cytologic diagnosis was giant cell sarcoma. The diagnosis was confirmed by histologic examination, and immunohistochemical staining was performed. The spindle-shaped cells and multinucleated giant cells were both immunoreactive for vimentin and spindle-shaped cells for S-100. Tumor cells did not express wide-spectrum cytokeratin, broad-spectrum muscle actin, smooth muscle actin, sarcomeric actin, desmin, BLA36, Mac 387, synaptophysin, neuron-specific enolase, glial fibrillary acid protein, or von Willebrand factor. These findings are most consistent with an anaplastic sarcoma with giant cells. This is the first case report of a primary ureteral giant cell sarcoma in a dog.     

Cervical teratoma in a dog

A young adult boxer dog was examined for a painless swelling in the left cranial cervical area that was refractory to antibiotic therapy. Ultrasound examination revealed a hypoechoic mass abutting the rostrolateral aspect of the left mandibular salivary gland. The cystic mass was excised and was found to extend through the capsule of the salivary gland and appeared to be confluent with the glandular tissue at this point. Histopathological examination of the excised tissue demonstrated tissue from all 3 germinal layers. There was no indication of malignancy and the mass was diagnosed as a benign cervical teratoma. Hypotheses regarding the origin of teratomas in general are discussed and the origin of the teratoma in this case is suggested.     

Cervical chondroid chordoma in a standard dachshund: a case report

A ten-year-old male standard dachshund was presented with a history of neck pain and progressive gait disturbances. Following a neurological examination and diagnostic imaging, including CT, a neoplastic lesion involving the third and fourth cervical vertebrae was suspected. The lesion included an extradural mass on the right side of the spinal canal causing a local compression of the cervical cord. Surgery, using a modified dorsal laminectomy procedure, was performed in order to decompress the cervical spinal cord. Histopathological examination of the extradural mass indicated that the tumour was a chondroid chordoma. Following discharge, the quality of life for the dog was very good for a sustained period, but clinical signs recurred at 22 months. The dog was euthanased 25 months post-surgery. On post-mortem examination, a regrowth of neoplastic tissue was found to have infiltrated the bone and spinal cord at C3-C4. This is the first report to show that palliative surgery can offer successful long-lasting treatment of chondroid chordoma of the cervical spine in the dog.     

Clinical,cytologic, and histologic features of a mammary micropapillary carcinoma in a dog

Mammary invasive micropapillary carcinoma is a rare variant of mammary carcinoma that was recently recognized in dogs. The cytologic features and biologic behavior of such neoplasms in dogs have not yet been widely discussed in the veterinary literature. We report the clinical, cytologic, and histologic features of a canine micropapillary carcinoma in a 13‐year‐old female mongrel dog. The mammary region presented with extreme local pain, severe edema and erythema, and multifocal epidermal ulceration, which is typical for an inflammatory mammary carcinoma. Fine‐needle aspirates were highly cellular and consisted of individual cells and papillary cell clusters with characteristics of malignant epithelial cells. Histologic examination revealed neoplastic cells arranged in small papillae without fibrovascular cores, sometimes inside clear lymphatic spaces, indicating lymphovascular invasion. Regional lymph node evaluation revealed metastatic cells. Due to deteriorating clinical condition the dog was euthanatized 5 months after mastectomy. At necropsy, metastatic neoplastic mammary cells were found in popliteal and mediastinal lymph nodes, the right femoral biceps muscle, liver, heart, lungs, and urinary bladder.     

Primary mesenteric root osteosarcoma in a dog

Abstract: A 10‐year‐old spayed female Boxer‐mix was presented with a history of several weeks of soft stools, straining to defecate, inappetance, and lethargy and several days of hematochezia, melena, and dyschezia. Physical examination findings included mild tachycardia and tense cranial abdomen. CBC results indicated moderate mature neutrophilia. Ultrasonographic examination of the abdomen revealed a large mass with complex echogenicity in the cranial abdomen, likely associated with the intestines. Cytologic examination of a fine‐needle aspirate revealed a population of round, stellate, and spindle‐shaped cells arranged individually and in aggregates with occasional cells embedded in an eosinophilic extracellular matrix. The cytologic interpretation was malignant mesenchymal neoplasm with osteosarcoma being the primary differential. Surgical exploration of the abdomen revealed a 10‐cm‐diameter mass located at the intestinal mesenteric root. The mass occluded blood flow to portions of the gastrointestinal tract. The dog was euthanized due to the nonresectable nature of the tumor. Histopathologic examination revealed an expansile poorly demarcated mesenchymal neoplasm composed predominantly of spindloid and pyriform cells, occasionally embedded in a matrix compatible with osteoid. The diagnosis was extraskeletal osteosarcoma of the intestinal mesenteric root, only rarely reported in dogs.     

Intramedullary spinal cord metastasis of a primary lung tumour in a dog

A dog was presented with signs of subacute, progressive myelopathy. A tentative diagnosis of a diffuse intramedullary spinal cord mass was made using contrast radiography (myelography). At autopsy a solitary, large bronchoalveolar carcinoma was detected in a lung lobe. Histological examination of the cranial thoracic spinal cord revealed a tumour which was similar, but not identical, to the lung tumour. Immunohistochemistry helped to confirm that the spinal lesion was a metastasis of the lung tumour.     

Choroid plexus carcinoma cells in the cerebrospinal fluid of a Staffordshire Bull Terrier

An 11-year-old female intact Staffordshire Bull Terrier was referred to the Queen's Veterinary School Hospital at the University of Cambridge with sudden onset of episodic behavioral changes, a mammary mass, and papilledema in the right eye. On physical examination the dog appeared depressed and had a head tilt to the right with anisocoria. Using magnetic resonance imaging, a broad-based lesion that obliterated the fourth ventricle was detected in the right brainstem. There was no evidence of pulmonary metastasis. Cerebrospinal fluid (CSF) was then obtained; fluid analysis showed an increased cell count (165 cells/μL, reference interval 0-7 cells/μL) and total protein (0.30 g/L, reference value <0.25 g/L). Cytologic evaluation revealed a population of atypical epithelial cells arranged in cohesive rafts and characterized by moderate to occasionally marked anisocytosis and anisokaryosis. The appearance was highly suspicious of a malignant epithelial neoplasm. The dog was euthanized and on postmortem examination an asymmetrical nonencapsulated cerebellar mass was found within the choroid plexus of the fourth ventricle with local extension into the cerebellopontine angle. Histologic sections of the cerebellar mass contained arborizing papillary structures covered by a single layer of atypical epithelial cells that showed local infiltration into the adjacent neuropil. The diagnosis was choroid plexus carcinoma. The atypical epithelial cells were negative for pancytokeratin and strongly positive for vimentin. The finding of clusters of choroid plexus epithelial cells in the CSF demonstrates the value of utilizing a relatively noninvasive diagnostic technique for diagnosis of choroid plexus tumors.     

Hypercalcaemia associated with a retroperitoneal apocrine gland adenocarcinoma in a dog

A seven-year-old, entire female golden retriever was presented with a history of polyuria/polydipsia and progressive dysuria. Clinical examination, radiography and ultrasonography demonstrated urinary retention due to a large soft tissue mass in the retroperitoneal space. Laboratory findings revealed paraneoplastic hypercalcaemia. Fine-needle aspiration cytology of the mass suggested an epithelial tumour, resembling an apocrine gland carcinoma of the anal sac. Following euthanasia and necropsy, the histopathological diagnosis of the retroperitoneal mass was apocrine gland adenocarcinoma. Despite ante- and postmortem examination, no perineal or anal sac tumour was found. The retroperitoneal tumour in this case could be a very large lymph node metastasis from an occult primary apocrine carcinoma of the anal sacs, or it could represent the first case of an ectopic apocrine gland carcinoma of the retroperitoneal space in a dog.     

Urethral haemangiosarcoma in a boxer

A seven-year-old, entire female boxer presented with a history of restless behaviour and inappetence. Physical examination revealed that the dog was listless and had a hunched gait. Neurological examination was normal. Abdominal ultrasonography revealed a 4 cm x 4 cm mass in the cranial pelvic canal. Neurological abnormalities were detected three days after presentation, and progressed from proprioceptive deficits to loss of deep pain sensation in the pelvic limbs over a two-day period. The dog was euthanased and postmortem examination revealed that the pelvic mass was a urethral haemangiosarcoma with metastasis to the second lumbar vertebra. This case is unusual as urethral tumours are usually transitional cell carcinomas and frequently present with signs of dysuria.     

Primary pulmonary osteosarcoma in a dog

An 11-year-old mixed breed dog was referred because of coughing and painful swelling of the distal extremities which had not resolved with antibiotic treatment. A consolidated left cranial lung lobe and hypertrophic osteopathy were identified by radiographs. A unique feature of this report is the marked, rapid reduction in pain and lameness associated with hypertrophic osteopathy after treatment with corticosteroids. Histological examination of an 8 cm diameter, spherical mass found in the excised cranial lung lobe revealed osteosarcoma. No evidence of local or distant metastases was present. The dog survived one year after diagnosis.     

Surgical removal of an intramedullary spinal cord foreign body granuloma in a dog

A 2-year-old, spayed female, mixed-breed dog was presented for evaluation of a progressive asymmetric tetraparesis and cranial nerve deficits with a 3-week duration. Computed tomography showed a contrast-enhancing lesion along the left side of the junction of the medulla and the cervical spinal cord. An exploratory surgery determined the presence of an intramedullary lesion of the first cervical spinal cord segment. The mass was removed through a dorsal midline myelotomy. Microscopic examination identified a foreign body granuloma that contained a dense, anisotropic outer wall, supporting the conclusion that the foreign body was of plant origin. The dog recovered to a more improved ambulatory status than prior to surgery.