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.     

Multinodular Malignant Cutaneous Mast Cell Tumor in a Horse With Generalized Pruritus and Reactive Fibrosis: A Case Report

Mast cell tumor (MCT) has long been considered as an uncommon neoplasm in horses. Cytological and behavioral evidence of its malignancy is usually lacking, and only a few reports have described MCT displaying malignant behavior. An 18-year-old Friesian stallion presented with a one-year history of intermittent and progressive skin lesions on the left forelimb associated with intense, generalized pruritus and apathy temporarily responsive to glucocorticoids and antibiotics. The horse was alert and responsive with poor body condition and marked generalized pruritus. The left forelimb was markedly enlarged and surrounded by numerous firm 2- to 20-cm masses that were ulcerated and focally necrotic. A 7-cm round firm mass was observed on the left dorsal neck. Dermatological examination revealed generalized moth-eaten alopecia and scaling with erosions and ulcers secondary to pruritus. A direct skin smear from the affected leg showed severe eosinophilic inflammation and neutrophilic inflammation with pleomorphic bacteria. Histopathology of the skin and biopsies of the underlying tissues revealed an abundant population of atypical mast cells consistent with a malignant MCT. The horse was euthanized and necropsy revealed a marked fibrous reaction on longitudinal sections of the affected limb, and the tumor could be detected on only a few histological slides. Diagnosis of equine MCT can be challenging because of the massive accompanying fibrous reaction. Mast cell tumor should be suspected in the presence of eosinophilic infiltration of the affected tissue and in cases of generalized pruritus not attributable to other causes.     

Ossifying fibroma in a llama.

A 4.5-year-old llama was admitted for evaluation of a firm mass rostral and ventral to the medial canthus of the left eye. Mucopurulent nasal discharge and absence of airflow through the left nostril were noted. Radiographs of the skull revealed a sharply demarcated soft tissue mass with faint mineralization. Endoscopy of the nasal passages revealed a mucosa-covered mass originating in the area of the second premolar, extending to the edge of the soft palate, and obstructing the airway. Examination of the oral cavity revealed a missing second molar and a mass protruding 2-cm from the empty alveolus. An ossifying fibroma, a previously unreported tumor in llamas, was diagnosed at postmortem examination.     

Retroperitoneal hemangiosarcoma causing chronic hindlimb lameness in a dog.

The clinical, radiographic, ultrasonographic, computed tomographic, surgical and histopathological findings in a Boxer dog with retroperitoneal hemangiosarcoma are described in this study. A seven-year-old, male, castrated Boxer dog was referred for evaluation of chronic hindlimb lameness. The physical examination revealed muscle atrophy and sciatic nerve deficits. Radiography and ultrasonography revealed a caudodorsal abdominal mass. Computed tomography revealed that the mass involved the left margin of the L7 vertebra, lumbosacral canal, and lumbosacral plexus. At surgery, a large retroperitoneal haematoma was removed. Histopathology of amorphous tissue found near the haematoma was consistent with haemangiosarcoma. The owner declined any further treatment. Ten weeks after discharge, the dog was euthanatized due to collapse and haemo-abdomen.     

Use of x-ray-computed tomography as an aid in localization of adrenal masses in the dog

Four dogs with clinical evidence of hyperadrenocorticism were evaluated by use of x-ray-computed tomography (CT). Adrenal masses were identified accurately and localized. Unilateral adrenal masses were diagnosed accurately in dogs 1, 2, and 3 and were removed surgically via a paracostal retroperitoneal approach to the adrenal gland. Using CT and IV contrast medium, the adrenal mass in dog 3 also was accurately diagnosed as being highly vascular. The histopathologic diagnosis was adrenal adenoma in dogs 1, 2, and 3. In dog 4, the CT-roentgen diagnosis was asymmetric bilateral adrenal enlargement. Necropsy examination of dog 4 indicated moderate enlargement of the left adrenal gland and severe enlargement of the right adrenal gland. Results of microscopic examination indicated chronic inflammation of the left adrenal gland and adenocarcinoma of the right adrenal gland. Use of CT facilitated localization of adrenal masses and fulfilled the needs of a localizing technique. A unilateral mass can be removed surgically via a limited exposure, retroperitoneal incision on the affected side of the animal instead of removal via abdominal laparotomy, which is more invasive. Advantages of CT can reduce the needs of other imaging modalities for the localization of adrenal masses.     

Retroperitoneal teratoma in a skunk (Mephitis mephitis).

A 4-yr-old striped skunk (Mephitis mephitis) developed an 11- x 7- x 7-cm retroperitoneal mass caudal to the left kidney. The mass was surgically excised and, on the basis of histology and immunohistochemistry, diagnosed as a benign teratoma. Six months later, a second histologically similar neoplasm was excised from the same location and was considered to represent local tumor recurrence. The skunk died 16 mo later without recurrence. Complete excision of the tumor appeared curative in this case and supported the benign diagnosis. An extragonadal teratoma should be considered as a differential diagnosis for an abdominal mass in a skunk.     

Cystic lymphangioma in a colt.

A 6-month-old Morgan colt was examined because of preputial edema and multiple nodular masses in the left inguinal region. A tentative diagnosis of lymphatic hamartoma was made on the basis of initial biopsy findings. The prognosis for surgical excision was poor due to the progressive expansile growth of the tumor. Secondary infectious complications developed, and the colt was euthanatized at the owner's request. An abdominal and retroperitoneal mass was seen at postmortem examination. The mass was adherent to the left lumbar musculature, the craniodorsal aspect of the pelvic inlet, the midjejunum, the left testicle, and the left kidney. The mass extended through the left inguinal and femoral canals into the deep intermuscular fascia of the hindlimb. Histologic examination of the mass indicated that it was a cystic lymphangioma.     

Ovarian adenocarcinoma with metastases in a white rhinoceros

A 36-y-old white rhinoceros (Ceratotherium simum) was presented with respiratory distress, sanguineous vaginal exudate, and anorexia. The clinical signs progressed over 40 d, and the rhinoceros died. Autopsy revealed significant ascites; a unilateral, 12.5-cm diameter, polypoid mass in the left ovary; a white, firm transmural mass in the right uterine horn; a white, friable mass in the lung; and white-to-tan, friable small nodules in the diaphragm. Histologic examination revealed similar neoplastic cells in the masses in all 4 locations, composed predominantly of epithelial cells proliferating in a tubulopapillary pattern with significant nuclear atypia and numerous atypical mitotic figures (18–42 per 2.37 mm²). Immunohistochemistry for CK7 (cytokeratin 7) and CK20 (cytokeratin 20) suggest that the ovarian, pulmonary, and diaphragmatic lesions were of ovarian origin and that the ovary was the primary tumor site.     

Sarcoids in two captive tapirs (Tapirus bairdii): clinical, pathological and molecular study

This case report describes for the first time sarcoids in tapirs (Tapirus bairdii), namely, a 2-year-old male and a 3.6-year-old female born and housed at the same facility. The male presented with a 3-cm nodular, red, pedunculated, hairless, ulcerated mass on the inner surface of the left pinna. No recurrence or additional growths were present during the 3 years following surgical excision of the mass. The female presented with a similar 2-cm mass on the inner surface of the right pinna, which recurred 2 months following surgical excision, but was subsequently successfully treated locally with liquid nitrogen with no further recurrence during a 2-year follow-up period. Histologically, these two masses closely resembled equine sarcoids. Similarly, an association with bovine papillomavirus 1 was demonstrated using polymerase chain reaction and in situ hybridization.     

Malignant melanoma of the horn base in a Pygora goat.

A case of malignant melanoma, originating at the base of the left horn, was diagnosed in a white 11-year-old Pygora doe. At necropsy, the goat had an ulcerated, black-pigmented, 2.5-cm mass at the base of the left horn. Firm masses diffusely black on the cut surface were present at the left horn base, subcutaneously over the frontal bones, and infiltrating into the frontal sinuses, the submandibular lymph node, and left parotid salivary gland. The left maxillary premolars and molars were loosened from the periodontia. Multiple black foci of metastasis were observed in the liver. Histologically, the masses consisted predominantly of moderately pleomorphic, polyhedral to spindle cells that contained variable amounts of dark brown intracytoplasmic pigment granules. The tumor cells were positive for Melan A by immunohistochemical staining.     

Computed tomography in the diagnosis of canine hyperadrenocorticism not suppressible by dexamethasone

Computed tomography (CT) was performed in 10 dogs with hyperadrenocorticism not suppressible by dexamethasone. In 6 of these dogs, a unilateral adrenal mass was found on CT images. Specimens of the masses were obtained via retroperitoneal laparotomy; histologic examination revealed 4 carcinomas, 1 adenoma, and 1 nodular hyperplasia. In the 4 other dogs, CT revealed symmetric bilateral adrenal gland enlargement. In 2 of these dogs, contrast-enhanced CT revealed a mass in the pituitary fossa, which could be identified at necropsy as a pituitary tumor. The other 2 dogs were successfully treated with mitotane.     

Ectopic pregnancy with uterine horn encapsulation in a cat

A 4 x 7-cm free-floating cylindrical mass was found in the abdomen of a 2 1/2-year-old domestic short-hair cat at ovariohysterectomy. The left uterine horn was absent. The mass contained 2 necrotic fetuses surrounded by tissue with the histologic appearance of uterine wall.     

Sciatic perineal hernia in two dogs

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.     

Post-traumatic paraureteral urinoma in a cat

A retroperitoneal urinoma (uriniferous pseudocyst) was diagnosed in a domestic shorthair cat exhibiting a sublumbar swelling two weeks after a road traffic accident. Plain radiography revealed a soft tissue opacity in the left retroperitoneal space. Intravenous urography and fine-needle aspiration were diagnostic. Contrast was seen pooling in the dilated ipsilateral renal pelvis and proximal ureter. Fluid aspirated from the retroperitoneal space had a creatinine level five times that of serum. Surgical drainage followed by nephrectomy and omentalisation of the pseudocyst was curative.     

Pleural effusion secondary to metastasis of an ovarian adenocarcinoma in a horse

An 11-year-old Quarter Horse mare was presented with ventral edema and pleural effusion, secondary to a disseminated ovarian adenocarcinoma. Bilateral thoracocentesis yielded 30 L of thin, blood-tinged fluid, which was a modified transudate. Cytologic examination of the fluid revealed large atypical cells, suggestive of carcinomatous neoplasia. Similar cells were found in the peritoneal fluid. The mare was euthanatized. Necropsy revealed a 35-cm diameter mass in the cranial mediastinum, ventral to the trachea. The left ovary was 25 cm in diameter and most of the parenchyma was replaced by red or brown friable tissue, containing numerous 1-to 3-mm cysts. Papillary adenocarcinoma of the ovary was diagnosed, based on the appearance and arrangement of tumor cells in the ovary, sublumbar and tracheobronchial lymph nodes, and mediastinal mass. Ovarian neoplasia should be considered in the differential diagnosis of pleural effusion in the horse.     

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.     

Genitourinary rhabdomyosarcoma with systemic metastasis in a young dog

A 2-year-old intact female Golden Retriever presented due to rapidly progressing depression, ascites, dysuria, abdominal pain, and severe vaginal bleeding. At necropsy, the retroperitoneal space was expanded by multiple coalescing neoplastic nodules and the uterine wall was thickened with poorly defined neoplastic infiltrates. The urinary bladder was markedly thickened due to botryoid nodules exhibiting exophytic growth into the lumen. Metastases to lung, liver, kidney, and abdominal and thoracic lymph nodes were also noted. Microscopically, the genital tract and retroperitoneal masses were consistent with the alveolar subtype of rhabdomysarcoma, while the urinary bladder mass had characteristics of the embryonal subtype. Immunohistochemically, the neoplastic cells in all these tissue sites were intensely positive for desmin, sacromeric actin, and vimentin, while they were uniformly negative for cytokeratin and smooth muscle actin. Phosphotungstic acid hematoxylin stain revealed cross-striations in the cytoplasm of scattered neoplastic cells. Based on the gross findings, histopathology, and immunohistochemistry, genitourinary rhabdomyosarcoma with multisystemic metastases was made.     

Thoracic, Abdominal and Vertebral Actinomycosis

The clinical, laboratory, radiographic, and histologic features and the response to therapy in three dogs with actinomycosis are reported. One dog (dog 1) had a 12-cm nonresectable mass extending from the ventrolateral chest wall into the left ventricular myocardium. Another dog (dog 2) had a diffuse peritonitis with "sulfur granules" and two large masses. One of these masses was nonresectable involving adjacent abdominal structures. A third dog (dog 3) had a subvertebral mass at T1-3 producing quadraplegia. Two dogs had periosteal reactions involving adjacent sternebrae (dog 1) or ribs and vertebral bodies (dog 3) that are characteristic of Actinomyces spp infections. In dogs 1 and 2 the diagnosis was based on the morphologic and tinctorial properties of free sulfur granules and/or tissue granules. Culture results were variable. Tissue from dog 1 yielded no growth, while polymicrobial infections, which included Actinomyces spp, were identified in dogs 2 and 3. Actinomyces odontolyticus was isolated from dog 3. Although the actinomycotic granulomas were either not excised or only partially excised from dogs 1 and 2, both animals were cured by the oral administration of high doses of penicillin G for 19 and 6 months, respectively. Dog 3 responded dramatically to the same antibiotic therapy given for 5 months. However, within 4 months of discontinuing treatment an abscess and draining fistulous tracts developed in the left axillary region. Two surgical fistulectomies and additional penicillin therapy were required to cure this animal. These cases and the current veterinary and human literature on actinomycosis are used to propose a rational approach to the treatment of actinomycosis in the dog.     

Cardiac hemangioma in a corn snake (Pantherophis guttatus)

A 3-yr-old female corn snake, Pantherophis guttatus guttatus, was presented for clinical examination of anorexia and a coelomic mass. Radiographs and ultrasound demonstrated a fluid-filled mass in the cardiac region. Surgical exploration revealed an approximately 1.2-cm, round, multilobulated, fluid-filled, nodular lesion firmly attached to the left atrial wall. Resection was attempted but proved unsuccessful and the animal was euthanized. Histopathological examination of the lesion revealed a large cystic structure associated with a cluster of variably sized, vascular channels lined by a one-cell-thick layer of endothelium, consistent with a cardiac hemangioma of the left atrium. This, to the best of the authors' knowledge, is the first report of such an occurrence in a snake.