Tubular duplication of the cervical portion of the esophagus in a foal.

Tubular duplication of the cervical portion of the esophagus was diagnosed in a 10-day-old female Quarter Horse. The foal was examined because of the development of a 12- to 15-cm diameter mass at the caudal aspect of the mandible after suckling. The foal was dyspneic when in lateral recumbency. Radiography and ultrasonography revealed a fluid- and gas-filled mass. Endoscopy revealed a normal-appearing upper airway and esophagus. Complete surgical resection of the mass was successful. The mass had a 3-mm diameter communication with the esophageal lumen at the pharyngoesophageal oriface. Histologic examination revealed stratified squamous epithelium lining the cyst-like cavity. The wall of the mass had circumferential and longitudinal layers of smooth muscle with few submucosal glands. The clinical, gross pathologic, and histopathologic findings were consistent with tubular duplication of the cervical portion of the esophagus.     

Unilateral leiomyoma in the mesosalpinx of a dog

Routine ultrasonographic evaluation of the genital organs of a 3-year-old terrier bitch revealed a mass at the level of the left ovary. The mass was located next to the caudal pole of the left kidney and ventrocaudal to the left ovary. Ultrasonographically, the uterus was not enlarged and had no luminal contents. Exploratory laparotomy revealed a mass attached to the left ovarian bursa with a small and thin pedicle. The mass had smooth margins, was whitish in color, and was lobulated on cut surface. The histopathological diagnosis of the mass was leiomyoma associated with the mesosalpinx.     

Intestinal choristoma in the midcervical region of a dog

A 5-year-old, neutered male, mixed-breed dog was evaluated for a fluctuant mass in the right midcervical region. The mass recurred following aspiration of its contents and after removal of the right sublingual and mandibular salivary glands. The lateral midcervical location of the mass and the serous nature of the fluid within the mass were inconsistent with a salivary mucocele. Excisional biopsy was curative and revealed an intestinal choristoma.     

Testicular neoplasia in the retained testicles of an intersex male dog

This case describes the presentation and management of an 8 yr old phenotypically female intersex male dog presented for evaluation of a mass in the right inguinal region. The right inguinal space was surgically explored, and a large irregular mass resembling a fully developed testicle was identified in the right vaginal tunic. A second mass resembling an atrophied, but anatomically mature testicle, was identified in the left tunic. The larger mass was identified as a Sertoli cell tumor that had replaced all normal testicular tissue. The smaller mass was identified as a testicle that contained a small intratubular seminoma. The patient was diagnosed as having a phenotypic female sex, chromosomal male sex, and a gonadal male sex. Hormone assays completed before and after the gonadectomy and mass removal document an elevation of circulating progesterone presurgically that returned to baseline by 1 mo postsurgically. The source of the progesterone was identified to be the Leydig cells of the atrophied testicle.     

Spontaneous adenolipoma of the mammary gland in the male F344 rat

A 110-week-old male F344 rat from the high-dose group of a 104-week carcinogenicity study, exhibited a spontaneously occurring subcutaneous mass in the left axilla extending to the chest. Histologically, the mass was well-demarcated from the adjacent mammary tissue and slightly encapsulated without evidence of infiltration into the surrounding tissues. The mass contained both epithelial and adipose components. The epithelial component consisted of ductal structures of various sizes lined by a single layer of flattened to cuboidal epithelial cells with relatively clear or vacuolated cytoplasm. These ductal structures were well-intermingled with an adipose component that consisted of a uniform monomorphic cell population of mature adipocytes. Both cell types were well-differentiated and did not exhibit cellular atypia. Within the mass, fibrous connective tissue was found in the stroma with infiltration of numerous mast cells. Based on these findings, the mass was diagnosed as an adenolipoma of the mammary gland.     

Radiotherapy of a recurrent ossifying fibroma in the paranasal sinuses of a horse

A 7-year-old female Thoroughbred was admitted with a history of labored breathing, stridor, and exercise intolerance. Examination revealed a mass in the left paranasal sinuses that was determined to be an ossifying fibroma. Initial treatment consisted of surgical removal of the mass alone; however, the mass recurred 9 months after surgery. The mass was again removed, and adjunctive radiotherapy consisting of 3,000 cGy of cobalt radiation was administered. This time, the tumor did not recur for > 6 years. A third surgery was performed to remove the mass, and adjunctive radiotherapy consisting of 4,000 cGy of photon beam radiation from a linear accelerator was administered. The mass did not recur during the subsequent 3 years. Ossifying fibromas are uncommon tumors that frequently recur if incompletely excised. Results in this horse suggest that adjunctive radiotherapy may delay or prevent tumor recurrence in affected horses.     

Fibro‐osseous tumour of the second metacarpal bone in a Thoroughbred filly

A 7‐month‐old Thoroughbred filly was evaluated because of an enlarging mass present on the proximomedial aspect of the left metacarpus. The mass was first noticed at age 2 months and had continued to increase in size. The mass was firm, nonpainful to palpation, covered with normal haired skin and had never been associated with lameness. Radiographs obtained at ages 2 and 7 months revealed an enlarging and partially mineralised mass associated with the second metacarpal bone. Based on the clinical and radiographic progression, as well as the location of the mass, a poor prognosis for future athletic soundness was given and the filly was subjected to euthanasia. The mass had histological features of both an ossifying fibroma and osteoma.     

Infiltrative lipoma in the heart of a horse

An expansile, yellow, soft mass was observed in the free wall of the right ventricle of a 3-year-old, male, Morgan, horse at necropsy. The mass was composed of well differentiated adipocytes in solid sheets or infiltrating between muscle fibers with associated myofiber degeneration. The mass was interpreted to be an infiltrative lipoma of the heart.     

Leiomyoma of the third eyelid in a dog

A 14‐year‐old neutered male Dachshund presented for the evaluation of oculus dexter (OD) third eyelid elevation ongoing for approximately 2 months. Complete ophthalmic examination revealed a large, nonpainful, well‐demarcated, soft mass at the base of the right third eyelid causing elevation and mild hyperemia. The mass was freely moveable with the third eyelid, and no right globe deviation was noted. No other abnormalities were noted on physical examination, routine blood chemistry, complete blood count, serum T4, urinalysis, or urine cortisol/creatinine ratio. Ocular B‐mode ultrasonography showed an anechoic, well‐demarcated, homogenous, soft tissue mass at the base of the third eyelid with no orbital extension. A leiomyoma was diagnosed after multiple punch biopsies were obtained from the palpebral surface of the mass. The right third eyelid was excised surgically. Histopathology confirmed a completely excised, nodular, unencapsulated, expansile mass within the third eyelid. Positive smooth muscle actin and negative S‐100 immunohistochemistry confirmed a leiomyoma. Bundles of normal smooth muscle were also present adjacent to the mass. The mass was compressing the adjacent lacrimal gland and associated with moderate dacryoadenitis. Twelve months postoperatively, the right globe position and motility remain normal with no evidence of mass regrowth. To the author's knowledge, this is the first reported case of a leiomyoma of the third eyelid in any species. In this case, the mass was completely excised and no regrowth has occurred twelve months after surgery. This case along with independently reviewed canine third eyelids clearly demonstrates the presence of smooth muscle within the canine third eyelid.     

Ontogenetic Scaling of the Hindlimb Muscles of the Greater Rhea (Rhea americana)

The greater rhea (Rhea americana) is the largest South American bird. It is a cursorial, flightless species with long powerful legs and reduced forelimbs. The goal of this study was to explore how hindlimb muscles scale with body mass during postnatal growth and to analyze whether the specialized locomotion of this species affects the growth of muscle masses. The mass of 19 muscles and body mass were weighed in 21 specimens ranging from 1‐month‐old individuals to adults. Seventeen muscles scaled with positive allometry with respect to body mass, whereas two muscles scaled isometrically . The predominance of positive allometric growth in hindlimb muscles results in a limb with massive and powerful muscles specialized to support a large body mass and to attain relatively high running speeds. Analysis of muscle mass scaling is a simple and useful way to compare possible differences between locomotor styles, and it is valuable in studies that reconstruct the paleobiology of extinct taxa.     

Micronema granuloma in the gingiva of a horse

A well-circumscribed proliferative mass was protruding from the body of the mandible of a 4-year-old Appaloosa gelding. The mass was uniformly firm and was ulcerated on the dorsal surface. The horse was euthanatized due to extensive involvement of the jaw and difficulty in eating. Microscopically, the mass consisted of numerous discrete microgranulomas separated by bands of abundant fibrous connective tissue containing lymphocytes, plasma cells, and histiocytic macrophages. Numerous rhabditiform nematodes were in the microgranulomas as well as in the surrounding connective tissue. The nematodes were identified as Micronema species.     

Congenital Osteoma of the Frontal Bone in an Arabian Filly

Congenital frontal osteoma has not been previously described in horses. This report records—for the first time—a congenital osteoma of the frontal bone in a 4-month-old Arabian filly. The filly had a frontal hard mass that was present at birth and then showed a slow and continuous growth. This mass appeared as a solitary, painless, oval dense tumor of compact bone, about 2 cm in diameter and 3 cm in length. The tumor was asymptomatic, and the skin over the mass was normal. Radiography revealed a well-defined oval, radio-dense mass projecting from the surface of the right frontal bone with no local invasion. The tumor had a broad-based attachment to frontal bone with normal frontal sinus. The mass caused disfigurement; therefore, it was removed at the owner’s request. The mass was diagnosed histopathologically as osteoma. The surgical excision of the osteoma was successful without any complications, and the filly adapted remarkably well after surgery. No recurrence was reported 20 months after the surgery. In conclusion, osteoma should be listed during the differential diagnosis of the congenital craniofacial masses in horses. Early diagnosis of the frontal osteoma guarantees a successful surgical treatment and consequently prevents the future complications.     

Adenocarcinoma of the frontal sinus with extension to the brain in a horse.

A space-occupying intracranial mass was diagnosed in a horse. The clinical findings included blindness, circling to the right, apprehension, anorexia, weight loss, and leaning against the stall. On ophthalmoscopic examination, the most striking observation was complete bilateral devascularization of the retinas. The horse was euthanatized and necropsied. Necroscopy revealed the mass to occupy the olfactory and frontal areas of the left hemisphere of the brain and part of the left frontal sinus. Microscopically, the mass was an adenocarcinoma and probably arose from the lining epithelium of the sinus or from the subepithelial glands.     

Benign masses in the pericardium of two dogs

Two miniature Schnauzer dogs were treated for pericardial masses. In one dog the mass consisted of necrotic fat that was attached to the apex of the pericardium by a pedicle. No obvious communication with the abdomen was present. The second dog had a peritoneopericardial hernia associated with a chronic cystic haematoma. In each case the mass was presumed to have arisen following congenital displacement of the omentum into the pericardium. The pericardial mass was removed and subtotal pericardectomy performed in both dogs. Recovery was complete in each case.     

Malignant peripheral nerve sheath tumor of the diaphragm in a dog

An 11-year-old, castrated male greyhound was referred to the Michigan State University Veterinary Teaching Hospital for surgical removal of a thoracic mass. Thoracic radiographs revealed a smoothly marginated mass obscuring the diaphragm in the left caudal thorax. Ultrasonographic and computed tomographic imaging modalities demonstrated a mass originating from the left hemidiaphragm. The mass was surgically removed and submitted for histopathological evaluation. Histopathology and immunohistochemical staining confirmed a malignant peripheral nerve sheath tumor.     

Leiomyosarcoma of the canine urinary bladder, with metastases

An enlarged nodular mass, assumed to be the prostate gland because of location and consistency, was palpated in the pelvic region of a 10-year-old German Shepherd Dog. Castration was performed as a therapeutic procedure after an estrogenic hormone failed to reduce the size of the mass. A tumor identified histologically as a seminoma was in the right testicle. The dog died 1 month after castration, and generalized metastatic neoplasia was observed at necropsy. The mass that involved the neck of the bladder and the metastases were identified as leiomyosarcoma.     

Idiopathic osseous hyperplasia of the nasal turbinates in a Welsh terrier

A three-year-old Welsh terrier was presented with a 6-month history of progressive stertor, exercise intolerance and sneezing which was unresponsive to symptomatic treatment. A large calcified mass occupying the entire rostral right nasal cavity was defined with computed tomography. The mass was completely removed via a dorsal rhinotomy. Histopathological examination of the mass revealed osseous hyperplasia of the nasal turbinates. The excision led to complete resolution of clinical signs and there has been no recurrence 18 months after surgery.     

HPLC-DAD-MSn 法分析恩诺沙星在兔血浆中的代谢产物

采用HPLC-DAD-MSn法对兔肌注恩诺沙星给药后血浆中恩诺沙星和代谢产物的紫外光谱和质谱裂解行为进行分析,获得各化合物的光谱和多级质谱信息。比较给药前后兔血浆的DAD检测色谱图,发现6个可能的代谢产物M1……M6。根据化合物结构和质谱裂解途径及标准品的色谱保留时间,确定M3为环丙沙星,并推测M5可能为加氧恩诺沙星;M4获得一级质谱数据和紫外光谱数据;M1、M2和M6仅得到紫外光谱数据。推测恩诺沙星在兔体内的主要代谢反应是脱乙基反应和氧化反应。     

En block resection of a large hepatocellular carcinoma involving the caudal vena cava in a dog

A 13-year-old neutered female Shih Tzu was referred for investigation of a cranial abdominal mass. Investigations including conventional radiography, abdominal ultrasonography and computed tomography confirmed the mass in the caudate lobe of the liver. As a collateral vein originating from the caudal vena cava (CVC) communicated with the azygos vein, the CVC was ligated and transected cranial to the right renal vein and cranial to the mass under temporary occlusion of the thoracic descending aorta and posthepatic CVC. The mass combined with the CVC was excised. The mass was confirmed as hepatocellular carcinoma (HCC). This report describes the first case with successful en bloc resection of a large HCC involving the CVC in a dog.     

Nonossifying fibroma in the mandible of a goat

An 8-year-old male Nubian goat was presented with a peracute history of straining to urinate and unilateral mandibular swelling. At necropsy, the rostral half body of the left mandible was distorted by fusiform swelling that, on sagittal section, had marked medullary bone loss and replacement with a well-demarcated fibrous mass. Histologically, the mass comprised streaming spindloid cells with whorls and storiform patterns, interspersed with numerous multinucleated giant cells. Bone formation was not present in the neoplasm. The mandibular mass was diagnosed as nonossifying fibroma, a relatively common tumor in children but seldom reported in domestic animals.