Detection of squamous cell carcinoma of presumed pancreatic origin and its metastasis in a spotted seal (Phoca largha) using ultrasonography and computed tomography

A 21-year-old female spotted seal (Phoca largha), with a swollen abdomen, had a five-month history of anorexia and vomiting. Ultrasonography revealed an extended mass with central necrotic foci in the right cranial abdomen. Computed tomography revealed an abdominal mass with a low-density central lumen and a pulmonary nodular lesion. Cytology of an abdominal specimen collected through fine-needle aspiration indicated a malignant tumor with round, atypical cells with large nuclei. Three days after diagnosis, necropsy revealed a 10-cm large, solid, whitish mass in the pancreatic parenchyma and multiple small nodules in the liver, spleen, mesentery, lungs, and mediastinal lymph nodes. Histopathological analysis showed prolific neoplastic cells with marked atypia and occasional keratinization. Immunohistochemistry revealed that the neoplastic cells were positive for cytokeratin AE1/AE3 antibody. Thus, the seal was diagnosed with squamous cell carcinoma, of presumed pancreatic origin, which had metastasized to multiple organs.     

Renal Cystic Adenocarcinoma in a Flowerhorn Cichlid with Metastatic Involvement of the Spleen

Abstract

A 480-g flowerhorn cichlid (an ornamental hybrid) with severe bilateral abdominal swelling, bulla-like structures on the skin, bilateral exophthalmia, and a prolapsed intestine was presented. Radiographs showed compression of the posterior part of the swim bladder and abdominal distention. Ultrasonography of visceral organs revealed a heterogeneous mass with hypoechoic to anechoic polycystic parenchyma and free fluid in the abdominal cavity. At necropsy, free fluid in the abdominal cavity and a large polycystic mass originating from the posterior kidney were observed. Histologically, the mass was composed of more cystic growth of tubules. The renal architecture was replaced by tubules, often irregular in shape, lined by simple to lightly stratified layers of neoplastic and pleomorphic cuboidal to columnar epithelial cells and the absence of glomeruli. Birefringent crystals were observed with polarized light within the lumen of some tubules. The apical border of the neoplastic cells was periodic acid–Schiff positive. Immunohistochemically, the neoplastic cells were positive for cytokeratin AE1/AE3 and proliferating cell nuclear antigen and were negative for p53 (tumor suppressor protein). Microscopic metastasis was seen in the spleen. The metastatic tumor was classified as a cystic adenocarcinoma of the kidney, originating from the proximal tubules.

Received October 7, 2016; accepted June 18, 2017 Published online July 31, 2017     

MYELOID NEOPLASIA IN A DOG

A 4-year-old Scotch Collie bitch was presented for examination because of hyperthermia and anaemia. Haematological examination and bone marrow biopsy led to a diagnosis of myeloid neoplasia. At autopsy there was slight enlargement of the liver, spleen and some lymph nodes. Microscopic examination revealed extensive infiltration of these tissues by neoplastic myeloid cells.     

Extramedullary plasmacytoma in a horse with ptyalism and dysphagia.

A Clydesdale mare was examined for weight loss, inappetence, ptyalism, and dysphagia. The main abnormality revealed by serum biochemistry was a marked hyperglobulinemia, and protein electrophoresis revealed a monoclonal gammopathy in the gamma region. The urine was positive for Bence Jones proteins. These findings suggested a plasma cell tumor. The neoplasm could not be located with extensive antemortem examination. At postmortem, neoplastic cells morphologically compatible with plasma cells and positive for equine IgG with imunoperoxidase staining infiltrated the pericardium, mediastinal stromal tissues, adrenal glands, meninges, atrioventricular valves, aorta, abdominal and thoracic fat, and nerves, including the trigeminal nerve. The neoplastic cells invading the cranial nerves were responsible for many of the presenting signs.     

Round cell variant of myxoid liposarcoma in a Japanese Macaque (Macaca fuscata)

A 5-year-old, female, Japanese Macaque (Macaca fuscata) was diagnosed with round cell variant of myxoid liposarcoma. At necropsy, multifocal to coalescing, reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum. Similar neoplastic nodules were also present in diaphragm, abdominal wall, and on hepatic capsule. Microscopically, neoplastic masses consisted of round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm. Ultrastructurally, the cytoplasm of the tumor cells was packed with occasional lipid vacuoles and numerous enlarged mitochondria. Immunohistochemistry revealed tumor cells were positive for vimentin, while negative to cytokeratin, actin, and Factor VIII-related antigen. To the authors' knowledge, this is the first report of round-cell variant of myxoid liposarcoma in nonhuman primate.     

Unilateral uterine torsion secondary to an inflammatory endometrial polyp in the bitch

A 9-year-old bitch was presented because of lethargy and abdominal distension. Abdominal ultrasound revealed an enlarged, fluid-filled uterus and associated mass. Subsequent exploratory laparotomy revealed unilateral uterine torsion involving the mass. Recovery following ovariohysterectomy was uneventful and the histopathological diagnosis was of a benign endometrial inflammatory polyp. Reports of uterine torsion in the English-language literature are reviewed to identify factors associated with the incidence of uterine torsion. The aetiology of the cystic endometrial hyperplasia/pyometra complex and its possible role in the development of inflammatory polypoid lesions in the bitch is also discussed.     

Lymphangiosarcoma in a 3.5-year-old Bullmastiff bitch with vaginal prolapse, primary lymph node fibrosis and other congenital defects

Lymphangiosarcoma is an extremely rare tumour in dogs with only 16 cases reported in the literature. Lymphoedema, which may be primary due to defects in the lymphatic system, or secondary to various other pathologies, often precedes malignancy. Of the 16 canine reports, only 1 dog was confirmed as having had prior primary lymphoedema due to aplasia of the popliteal lymph nodes. A case of lymphangiosarcoma is described in a 3.5-year-old purebred, Bullmastiff bitch which presented with vaginal blood 'spotting' for 3 weeks after cessation of oestrus, during which intromission by the male had been unsuccessful. During ovariohysterectomy a large multicystic, proliferative, spongy, fluid-filled, brownish-red mass surrounding the cervix and projecting into the abdominal space was removed with the cervix, and a diagnosis of lymphangiosarcoma made on histological and electron microscopic examination of the tissue. Ultrastructurally, no basement membrane or pericytes were found, only some of the neoplastic endothelial cells were linked by tight junctions while there were gaps between others, and neither micropinocytotic vesicles nor Weibel-Palade bodies occurred in the cells examined. Very few of the endothelial cells lining the many interlinking, tortuous maze of channels, stained slightly positive immunohistochemically for factor VIII-related antigen. The channels were filled mostly with serous fluid, and occasionally mixed leucocytes and some erythrocytes. The endothelium was often associated with underlying blocks of collagenous material, as well as loosely-arranged aggregates of lymphocytes, other mononuclear cells and occasional neutrophils in the connective tissue septae and more prominently perivascularly. The bitch was discharged on antibiotic treatment but returned 2 weeks later with apparent prolapsed vagina which failed to reduce over the next week. Laparotomy revealed the tumour to have spread extensively in the caudal abdomen to involve the broad ligament and the ventral rectal serosa, and the 'prolapsed' tissue was found to be expanded vaginal wall. The bitch was euthanased and necropsied, Histological examination confirmed lymphangiosarcomatous invasion of the submucosal and muscular layers of the retroperitoneal, traumatised, prolapsed part of the vagina, the urethra and the ventral rectal wall. The broad ligament was diffusely invaded with tumour which had proliferated into the caudal abdominal space, and 3 small intra-trabecular foci of tumour were found in the right popliteal lymph node near the hilus. Mitotic figures were generally scarce. There was mild subcutaneous oedema of the ventral trunk extending from the axillae to the inner proximal thighs, which had not been evident clinically, and the lymph nodes (peripheral more so than internal) microscopically showed marked trabecular and perivascular fibrosis especially in hilar regions. Other congenital defects were hepatic capsular and central venous fibrosis with lymphatic duplication and dilatation in all areas of connective tissue, ventrally-incongruous half-circular tracheal rings, and multifocal renal dysplasia affecting the right kidney. There was locally-extensive subacute pyelonephritis of the left kidney.     

Feline mesothelioma: case report and review of cytologic,immunocytochemical, histopathologic,and immunohistochemical findings

Mesotheliomas are uncommon neoplasms that arise from mesothelial cells in either the abdominal or thoracic cavities and are rarely diagnosed in cats. A 10-y-old spayed female domestic shorthair cat was presented to the Louisiana State University oncology service for evaluation of a large amount of abdominal effusion. Abdominal ultrasound identified a large mesenteric mass with numerous ill-defined nodules. An abdominocentesis was performed with cytologic and immunocytochemical findings consistent with a neoplastic effusion, with large clusters of epithelioid cells that exhibited strong cytoplasmic expression of pancytokeratin, vimentin, and Wilms tumor 1 antigens. Further testing was declined, and meloxicam was prescribed until the cat died 23 d after initial presentation. Upon postmortem examination, the omentum was contracted into a firm mass adhered to multiple organs and accompanied by numerous small white nodules throughout the abdominal cavity. On histopathology and immunohistochemistry, neoplastic cells were found throughout the abdominal cavity; 60–95% exhibited moderate-to-strong cytoplasmic immunoreactivity for cytokeratin, vimentin, and Wilms tumor 1 protein. The final diagnosis was an epithelioid mesothelioma. Our case illustrates the utility of cytology, immunocytochemistry, and its relation to histology and immunohistochemistry. We also reviewed the reported cases of feline mesothelioma.     

Pericardial mesothelioma in a neonatal calf

We encountered an extremely rare tumor, a pericardial mesothelioma, in a neonatal calf. The patient calf showed severe abdominal distention, and died immediately after birth. The thoracic cavity was contained a huge heart with a large amount of pericardial fluid. A number of granular and cobblestone-like nodules were dispersed over the epicardium and pericardium. The nodules consisted of papillary proliferations of neoplastic cells, and the neoplasm occasionally showed mesenchymal proliferations. Immunohistochemistry revealed that they had the characteristics of mesothelial cells (cytokeratin-and vimentin-positive), and the neoplasm was diagnosed as mesothelioma.     

The lymph drainage of the neoplastic mammary glands in the bitch: a lymphographic study

The purpose of this investigation was to study the lymph drainage of the neoplastic mammary glands in the bitch using indirect lymphography. The main conclusions drawn from the study of 41 natural cases were as follows: the first or cranial thoracic and second or caudal thoracic neoplastic mammary glands usually drain into the ipsilateral axillary lymph nodes and rarely into the ipsilateral axillary and sternal lymph nodes, simultaneously. The third or cranial abdominal neoplastic mammary gland usually drains into the ipsilateral axillary and superficial inguinal lymph nodes simultaneously, but sometimes only cranially into the ipsilateral axillary lymph nodes. Rarely, it drains only caudally into the ipsilateral superficial inguinal and medial iliac lymph nodes, simultaneously. The fourth or caudal abdominal neoplastic mammary gland usually drains only caudally into the ipsilateral superficial inguinal lymph nodes. Rarely, it drains into the ipsilateral axillary and superficial inguinal lymph nodes simultaneously. The fifth or inguinal neoplastic mammary gland usually drains into the ipsilateral superficial inguinal lymph nodes but rarely, does it also drain into the ipsilateral popliteal lymph node and into a lymphatic plexus at the medial aspect of the ipsilateral thigh. Lymphatic connections between the neoplastic and adjacent normal mammary glands were demonstrated in only one case. The lymph drainage pattern of the neoplastic mammary glands is slightly different to that described in normal glands using the same radiographic method.     

Lymphangiosarcoma with bone formation of the auricle in a dog

A 12-year-old mixed-breed neutered female dog was referred with cutaneous tumors at the left auricle. Histologically, the cutaneous tumor located in the dermis comprised numerous clefts and cavernous channels lined by neoplastic endothelial cells with no erythrocytes. Bone tissue without direct contact with neoplastic cells was seen in the well-developed stromal connective tissue. The neoplastic endothelial cells exhibited mild to moderate atypia. Immunohistochemically, neoplastic cells were positive for vimentin and negative for cytokeratin and factor VIII-related antigen. Basement membrane around the neoplastic lumens was positive for laminin in a linear or granular pattern. Ultrastructural examination revealed discontinuous basement membrane beneath the tumor cells. Histopathological features of this case were consistent with lymphangiosarcoma, and stromal ossification was characteristic.     

Lymphosarcoma and associated immune-mediated hemolytic anemia and thrombocytopenia in horses

Three horses with equine lymphosarcoma were examined because of clinical signs including chronic weight loss, respiratory distress, peripheral edema, and chronic colic. Clinicopathologic findings included evidence of an immune-mediated hemolytic anemia. Immune-mediated thrombocytopenia also was diagnosed in 1 of the horses and suspected in another. One horse died in spite of treatment, 1 died 5 hours after surgical removal of a tumor encircling the jejunum, and 1 was euthanatized because of deteriorating condition. Necropsy of each horse revealed extensive neoplastic infiltration of peripheral lymph nodes and abdominal or thoracic viscera with neoplastic lymphocytes.     

A huge ovarian cyst in a hysterectomized bitch

A 11-year-old, spayed, female mixed breed-dog was presented with an abdominal mass that was detected 1 month ago. Upon abdominal palpation a large, firm, oval shaped, movable mass was found in the mid-abdominal region. Survey radiograph of the abdomen demonstrated an oval soft tissue dense mass located on the right side of the abdominal cavity. A large, heteregenous and cystic mass with solid components occupying the majority of the abdomen and a small, cystic mass with solid components caudal to the left kidney were identified by transabdominal ultrasonography. Computed tomography scans revealed bilateral ovarian masses, and a small volume of retroperitoneal fluid on the right side. A cystic, but otherwise solid mass located in the right ovary and small retained left ovary encapsulated in the ovarian bursa were excised surgically by midline laparotomy. Histopathological examination of the excised mass from the right side revealed a large cystic structure consistent with an ovarian cyst and multiple corpora lutea and follicles at different maturational stages were detected in the left ovary. The precise origin of the ovarian cyst could not be determined by morphological appearance. Immunohistochemical staining suggested a cyst of surface epithelial origin. At re-examination 6 months after the surgery, the bitch appeared healthy and the clinical findings were all normal. To our knowledge, the cyst described here is the largest reported in an incompletely ovariohysterectomized bitch.     

Rhabdomyosarcoma in the abdominal cavity of a 12-month-old female donryu rat

Neoplasms of skeletal muscle origin are very rare in the rat. Recently, we experienced a case of rhabdomyosarcoma as a white mass involving the junction of the esophagus and stomach in the abdominal cavity of a 12-month-old female Donryu rat. Histopathologically, the neoplastic cells composing the mass invasively spreaded from the lamina propia to the tunica serosa in the stomach as well as the esophagus. Although the neoplastic cells varied in appearance, pleomorphic atypical cells with abundant eosinophilic cytoplasm were prominent. Some tumor cells were stained blue with phosphotungstic acid hematoxylin. The nuclei of spindle-shaped neoplastic cells were arranged longitudinally like beads. Multinucleate giant cells and mitotic figures were also frequently observed. Immunohistochemically, these neoplastic cells were positive for desmin and myoglobin, whereas they were negative for alpha-smooth muscle actin. Taken together these findings, this tumor was diagnosed as a pleomorphic rhabdomyosarcoma, probably derived from the muscle layer of the lower part of the esophagus. This is the first report of rhabdomyosarcoma in a Donryu rat.     

Partial hepatectomy in two dogs

A 10-year-old Jack Russell terrier bitch and a nine-year-old standard dachshund bitch were presented with abdominal enlargement and weight increase; neither had a history of ill health. In each case an extensive soft tissue mass was clearly palpable in the abdomen and following an exploratory laparotomy a partial hepatectomy was performed. Both bitches made a good postoperative recovery followed by a normal active life. In each case the survival time was six months before renewed tumour development lead to a sudden and rapid decline; case 1 was euthanased and case 2 died peacefully.     

Polyostotic hyperostosis associated with oviductal tumor in a cockatiel

A 10-year-old female cockatiel in a thin and depressed condition and with a 1 X 2-cm soft abdominal swelling was hospitalized. Radiography revealed a well-circumscribed mass containing punctate areas of mineralization, displacing the gizzard cranially in the caudodorsal portion of the abdomen. There was bilateral, symmetric, generalized, increased medullary opacity of the radius, ulna, carpometacarpus, femur, tibiotarsus, and tarsometatarsus. These findings were compatible with polyostotic hyperostosis secondary to an estrogen-secreting tumor. Euthanasia and necropsy were requested. A small area of neoplastic cells in the oviduct was identified histologically, but most of the tissue mass consisted of necrotic cellular debris. There was no metastasis. Sagittal secretions of decalcified radiopaque bones revealed up to 60% filling of medullary cavities with bone spicules. Although clinical and radiographic findings were compatible with an estrogen-secreting tumor, osteopetrosis, metastatic neoplasia, hypertrophic osteopathy, and metabolic bone disease were included in the initial differential diagnosis. The absence of metastasis and the confinement of the tumor within the oviduct would have made surgical removal a possible approach to treatment.     

Sertoli cell tumor associated with polyomavirus infection in a Gouldian finch (Erythrura gouldiae)

A 3-yr-old male Gouldian finch (Erythrura gouldiae) died after 2 wk of lethargy, emaciation, feather loss, and abdominal distension. The bird was housed in an aviary for breeding, but it had shown loss of fertility in the previous breeding season. Necropsy revealed a gross, firm, and yellow mass involving the left testis. Histologically, the mass was a mixed form, intratubular and diffuse, Sertoli cell tumor. Some neoplastic cells had intranuclear inclusion bodies that immunoelectron microscopy proved to be polyomavirus particle aggregates. There were no viral inclusions in other tissues. The possible role of infection in the pathogenesis of the tumor is discussed.     

Pelvic limb lameness due to malignant melanoma in a horse

Malignant melanoma in a 21-year-old, gray, Arabian gelding was manifested by rapidly deteriorating lameness of the right pelvic limb. A melanotic, cutaneous mass of small dimensions was identified in the left jugular furrow. Exploratory laparoscopy revealed widespread infiltration of melanotic masses into the structures of the abdominal cavity. Necropsy indicated the lameness to have resulted from infiltration of neoplastic cells into the sacral nerves, dorsal root ganglia, proximal ischiatic nerve, and gluteal muscle fibers. The primary tumor could not be identified.     

Comparative genomic hybridization in detection of DNA changes in canine lymphomas

In this study, chromosomal imbalances in tumor tissues (lymphomas) and nucleotide changes in tumor suppressor TP53 were studied in a Bernese Mountain dog bitch and a cross breed bitch. Using comparative genomic hybridization, numerous chromosomal rearrangements were detected, which indicated the heterogeneity in tumor growth: in the cross breed bitch, a deletion on the chromosome 9, and duplications on chromosomes 5, 8 and 17 have been found. In the Bernese Mountain Dog bitch, losses on chromosomes 1, 5, 8, 12, 18, 22, 27, 29 and gains on chromosomes 1, 2, 9, 11, 15, 16, 18, 20, 23, 24, 25, 28, 29, 30, 34, 36, 37 and 38 were identified. With the sequencing of the TP53 gene, one silent mutation, transition A/G at position 138 in exon 5 was detected, without changing the amino acid.