Canine osteosarcoma of the penile bone

A 13-year-old mixed breed dog was presented with difficulties to urinate, blood in the urine and a nodule at the root of the penis. The penis was completely resected, and an osteosarcoma of the penile bone was diagnosed. Radiographically, there was no evidence to suggest tumours in other bones or distant metastases. The dog was euthanized as a consequence of tumour recurrence after 2 months. This is believed to be the first reported case of a primary osteosarcoma of the penile bone.     

Priapism secondary to penile metastasis in a dog

A 4-year-old, male Newfoundland cross was presented for lethargy, anorexia, and dysuria. The main clinical finding was an enlarged and painful prostate gland. While the dog was hospitalized, priapism developed. Following euthanasia, microscopic examination revealed that a carcinoma involving both bladder and prostate gland had widely metastasized to the penile vasculature.     

Reduced birth weight,cleft palate and preputial abnormalities in a cloned dog

The aim of the present study was to report a novel developmental abnormality in a cloned dog. A fibroblast cell line was established from an 8-year-old male German shepherd dog. In vivo matured oocytes were retrieved from a large breed dog, and the nucleus was removed from each oocyte. A donor cell was injected into an enucleated oocyte, and the oocyte-cell couplet was fused electrically. After chemical activation, the resulting embryos were transferred into a naturally estrus-synchronized recipient dog, and two cloned pups were delivered by Cesarean section 60 days later. One cloned pup (Clone 1) was healthy, but the other (Clone 2) had a birth weight of only 320 g and cleft palate, failure of preputial closure at the ventral distal part, and persistent penile frenulum. Clone 2 was raised by stomach feeding until Day 40 after birth, where palatoplasty was performed. The abnormalities in external genitalia in Clone 2 resulted in persistent penile extrusion that was surgically corrected. This complex developmental abnormality has not been reported in dogs previously.     

Penile prolapse and urethral obstruction secondary to lymphosarcoma of the penis in a dog

A 5-year-old Chihuahua presented for clinical signs of dysuria and penile prolapse. Radiographic studies identified a urethral obstruction distal to the junction of the proximal and middle third of the os penis that appeared to be secondary to swelling of the penis. Penile resection combined with a scrotal urethrostomy was performed. Histopathological examinations of tissue samples of the body of the penis revealed lymphosarcoma. Lymphosarcoma of the penis is a rare finding in all species. It can occur as a primary tumor of the penis in dogs. Penile lymphosarcoma should be considered in the differential diagnosis of dogs affected with penile prolapse and dysuria.     

Outcome of a dog with urinary bladder osteosarcoma treated with a total cystectomy and ureterocutaneostomy

A 10-year-old, neutered female, French bulldog was presented with a history of dysuria, hematuria, stranguria, and pollakiuria. Diagnostic tests revealed a large mass at the neck of the bladder without any evidence of metastatic disease. Total cystectomy with bilateral cutaneous ureterostomy creation was elected. Histopathology of the bladder mass revealed extraskeletal osteosarcoma, which was resected completely. Neither recurrence nor metastasis had been detected as of 65 months after surgery. Extraskeletal osteosarcomas are typically malignant and carry a poor prognosis. This is the first report of bladder osteosarcoma in a dog treated by total cystectomy and ureterocutaneostomy with excellent long-term control.     

Osteosarcoma of the humeral head associated with osteochondritis dissecans in a dog

A 6-year-old, male Labrador retriever was presented for lameness of the right forelimb. The lameness occurred 5 years after the dog was surgically treated for osteochondritis dissecans (OCD) of the caudal right humeral head. Radiographs revealed an expansile, osteolytic lesion occupying the entire caudal half of the right humeral head, and biopsy confirmed the diagnosis of osteosarcoma. Forelimb amputation was performed. Histopathology of the lesion and associated articular cartilage revealed neoplastic osteoblasts extensively infiltrating the marrow space adjacent to scar tissue associated with the previous OCD lesion. This is the first report of an epiphyseal osteosarcoma in the area of a previous OCD lesion in a dog.     

Radiographic diagnosis of an expansile bone lesion in a dog

An old dog had an expansile lesion affecting the ulnar diaphysis. The lesion had clinical and radiographic features typical of a bone cyst; however, computed X-ray tomography indicated that the lesion had a tissue content incompatible with a true cyst. The histological diagnosis was osteosarcoma. This report emphasises the highly variable radiological appearance of canine osteosarcoma; biopsy is required to establish the diagnosis because the radiological signs may mimic a lesion of different aetiology.     

Contemporary use of acepromazine in the anaesthetic management of male horses and ponies: a retrospective study and opinion poll

Reason for performing study: Current use of acepromazine in the anaesthetic management of male horses and ponies and associated risks are largely unknown. Objectives: To explore anaesthetic acepromazine use and related adverse effects in the male horse. Methods: Of 8533 anaesthetised horses and ponies medical records of male animals treated perianaesthetically with acepromazine were reviewed. Demographic data, time and dose of acepromazine administration, co‐administered drugs, quality of induction and recovery from anaesthesia, arterial blood pressures, and occurrence of penile dysfunction were recorded. Practising ACVA and ECVAA diplomates were polled on the use of acepromazine and its effects on blood pressure and penile dysfunction in the equine. Results: Of all animals, 12% females and 11% males (n = 575 including 42% stallions) received perianaesthetic acepromazine, predominantly for premedication. Anaesthetic induction was smooth in 566 animals. Lowest mean arterial pressures averaged 65 ± 9 mmHg. Recovery was good or very good in 70% of all animals and 74% stood after 1–2 attempts. In 14 horses (2.4%; 7 stallions, 7 geldings), penile prolapse occurred for 0.5–4 h and in one stallion (0.2%) for >12 but <18 h post recovery. Most surveyed anaesthesiologists use acepromazine in stallions (occasionally 63%; frequently 17%) but more frequently in geldings (occasionally 34%; frequently 59%) and mares (occasionally 38%; frequently 59%), primarily for premedication with other sedatives and analgesics. Persistent intraoperative hypotension was not frequently reported. Only 5% of surveyed anaesthesiologists recall penile prolapse post acepromazine administration lasting for >12 h and only one recalls 3 cases of irreversible penile prolapse in 20 years of anaesthesia practice. Conclusions and potential relevance: The extremely low risk of permanent penile dysfunction (≤1 in 10,000 cases) does not justify more restricted use of acepromazine in the intact male vs. geldings and mares.     

SCINTIGRAPHIC DETECTION OF SUBCUTANEOUS METASTASIS IN A DOG WITH APPENDICULAR OSTEOSARCOMA

This report describes the detection of subclinical soft tissue metastasis of an appendicular osteosarcoma in a dog using bone scintigraphy. A 7-year-old spayed female Rottweiler was presented with a biopsy confirmed diagnosis of osteosarcoma. Initial radiographs revealed an aggressive bone lesion of the left distal radius. At presentation, there was no clinical or radiographic evidence of metastasis; however, a nuclear bone scan showed the primary bone lesion of the distal left radius and numerous soft tissue lesions consistent with diffuse soft tissue metastases. A left foreleg amputation was performed and cisplatin chemotherapy was given post-operatively. A second bone scan performed one month following initial presentation showed progression in size and number of soft tissue masses. Many of the lesions had become apparent on physical exam and survey radiographs. Excisional biopsy was performed on one of the soft tissue masses and a diagnosis of metastatic osteosarcoma was made. The dog was euthanized 2 months after initial presentation at the owners request due to deterioration of the animals physical condition.     

Hemothorax associated with telangiectatic osteosarcoma in a dog

Hemothorax in a dog was attributed to bleeding from an intrathoracic mass attached to the sixth through the tenth ribs. The mass contained numerous cavernous, blood-filled spaces as well as bands of osteoid and occasional foci of osseous tissue. The diagnosis was telangiectatic osteosarcoma. Telangiectatic osteosarcoma is an uncommon variant of osteosarcoma. Cavernous, blood-filled spaces and paucity of bone are important histologic features. Metastasis was described in one of the seven telangiectatic osteosarcomas reported in dogs, and none was found in this case.     

High-grade surface osteosarcoma in a dog

A case of a high-grade surface osteosarcoma in the thoracic limb of a dog is reported. Radiographically, there was no bone involvement but there was increased soft tissue opacity. An aggressive osteosarcoma was diagnosed on the basis of early metastatic disease and histopathological examination. Previously reported surface osteosarcomas in the dog have been periosteal and parosteal osteosarcomas which are generally considered to have a low to intermediate biological activity. The tumour described here had radiographical, gross pathological, histopathological and biological features consistent with human high-grade surface osteosarcoma. The characteristics of surface osteosarcomas are briefly reviewed.     

Extraskeletal osteosarcoma associated with retained surgical sponge in a dog.

Retained surgical sponges are usually discovered in the abdominal cavity, sometimes years after the surgical procedure, and the typical reaction is formation of a foreign-body granuloma, often called gossypiboma or textiloma. In this instance, an extraskeletal osteosarcoma, associated with the granulomatous reaction to a retained surgical sponge adjacent to the stifle, was diagnosed in an 11-year-old Labrador Retriever 9 years after repair of a ruptured cranial cruciate ligament. Radiographic detection of linear foreign material in the soft tissue mass was the basis for a diagnosis of gossypiboma. The mass was surgically excised. Histologically, fibers consistent with those of cotton gauze were associated with the granulomatous inflammation and the osteosarcoma. Amputation or radiation therapy was declined; the dog was treated conservatively with doxycycline and deracoxib. Three months after surgical excision, the dog was euthanized because of local recurrence of the mass along with lameness and decreased appetite.     

OSTEOSARCOMA OF THE PATELLA WITH PULMONARY METASTASES IN A DOG

A 6-year-old neutered male Rottweiler was examined for a progressive right pelvic limb lameness. In radiographs of the right stifle, there was an osteolytic lesion with irregular new bone formation along the cranial aspect of the patella consistent with an aggressive bone lesion. In thoracic radiographs, there were multiple soft tissue nodular opacities throughout the lung fields, consistent with pulmonary metastases. Microscopically, fine needle aspirate samples from the right patella contained pleomorphic spindle cells with cytologic features of osteosarcoma. The presence of pulmonary metastases at the time of initial diagnosis in the dog described herein suggests that osteosarcoma of the patella has the potential for similar aggressive biologic behavior as that seen in dogs with appendicular osteosarcoma.     

Mandibular ossifying fibroma in a dog

An aged mongrel dog was admitted for hemimandibulectomy as treatment for a mandibular mass that had been diagnosed as osteosarcoma. The fibro-osseous mass that surrounded the first molar tooth and replaced alveolar and cortical bone was reclassified as ossifying fibroma on the basis of anatomic location and histologic features. The tumor was composed of isomorphic fusiform cells with few mitotic figures. Tumoral stroma contained trabeculae of woven bone that were bordered by a single layer of osteoblasts. Excision was deemed complete with no evidence of extension or metastasis by computed tomography of the skull or thoracic and abdominal radiography. The dog was reportedly healthy 6 months after initial presentation. Though far less common than osteosarcoma as a primary canine bone tumor, ossifying fibroma should be included in the differential diagnosis for fibro-osseous proliferations, especially those of the jaw. Although benign, en bloc excision may be necessary for surgical cure.     

Primary osteosarcoma of the synovium in a dog

An eight-year-old, spayed female Labrador retriever was presented for evaluation of left thoracic limb lameness. Radiographs of the left elbow revealed mineralization of the soft tissues surrounding the joint, with no evidence of periarticular bony lysis. Biopsy of the synovial tissues of the left radiohumeral joint yielded a diagnosis of osteosarcoma (OSA). The dog was treated with palliative radiotherapy, piroxicam, and carboplatin chemotherapy, which resulted in excellent pain control for approximately eight months. Amputation of the affected limb was then performed. Six months later, the dog developed multiple subcutaneous OSA metastases, and the dog was euthanized 15 months after diagnosis due to refractory vomiting. This report documents the first known case of primary OSA of the synovium in any species.     

PAROSTEAL OSTEOSARCOMA OF THE CERVICAL VERTEBRA IN A DOG

A 12-year-old Maltese terrier was evaluated for progressive tetraparesis and neck pain. On radiographs, there was a periosteal reaction involving the fourth cervical vertebra. Myelographically, there was extradural compression of the spinal cord associated with the lesion. The dog was euthanized and necropsied. Histopathologic diagnosis was parosteal osteosarcoma of the vertebra.     

BONE SCINTIGRAPHY FOR METASTASIS DETECTION IN CANINE OSTEOSARCOMA

The purpose of this study was to assess the usefulness of serial bone scintigraphy in the detection of skeletal and extraskeletal metastases in dogs with appendicular osteosarcoma. Twenty-six dogs with primary, appendicular osteosarcoma were entered into a limb-sparing protocol. Bone scintigraphy was performed upon presentation, after neoadjuvant therapy but prior to surgery and at selective intervals after limb-sparing surgery to evaluate for the presence of metastasis. Thoracic radiographs, and radiographs of other sites, were also made at the time of each bone scan. All dogs had a complete necropsy. No dog had bone or lung metastases detected prior to treatment. The bone scans, medical records, and radiographs of each dog were reviewed retrospectively. All but one dog developed metastatic disease. Bone metastatic sites were confirmed at necropsy in 12 of the 26 dogs. Seven of these 12 dogs had bone metastatic sites which were not producing clinical signs, i.e. an occult metastasis. In five of the seven dogs, the occult site was the first metastatic site detected. Extraskeletal metastases were identified scintigraphically in six of the 26 dogs, but these were clinically apparent prior to bone scintigraphy in each dog. Suspected malignant scintigraphic lesions were proven benign in six dogs. In five dogs with malignant bone lesions at necropsy the last bone scan prior to euthanasia was normal. The time interval between scintigraphy and necropsy was variable in these five dogs. All dogs without bone metastases at necropsy had normal bone scans. This study validates the usefulness of bone scintigraphy for detection of occult bone metastasis and improved ability for tumor staging in dogs with appendicular osteosarcoma.     

Functional urethral obstruction in 3 dogs: clinical and urethral pressure profile findings

Three dogs with dysuria and urine retention caused by excessive functional urethral resistance are described. All dogs had clinical histories and urologic signs that previously would have been classified as detrusor-urethral dyssynergia. Diagnosis of functional urinary obstruction was established by exclusion of anatomic urinary obstruction and confirmed by urethral pressure profilometry. In 2 cases, multiple pressure deflections recorded in the urethral pressure profile suggested spasm of urethral musculature, whereas in a 3rd dog, abnormally high pressures were recorded along a portion of the proximal urethra. Functional urinary obstruction was associated with prostatitis in 1 dog and with a history of urethral calculi in 1 dog, and no underlying disorder could be identified in the remaining dog. All 3 dogs improved with medical treatments that included alpha adrenergic antagonists. The etiology, diagnosis, and pharmacologic management of functional urinary obstruction are discussed.     

OSTEOSARCOMA WITH A PATHOLOGIC FRACTURE IN A SIX-MONTH-OLD DOG

This case history report describes the clinical, radiographic, and histopathologic features of an osteosarcoma with an associated pathologic fracture in a 6-month-old dog. A 6-month-old intact male Bloodhound was presented with a primary complaint of a right forelimb lameness of one month's duration. In radiographs, a minimally displaced transverse fracture of the proximal humeral metaphysis was seen. There was extensive cortical bone destruction at the fracture site and minimal periosteal new bone suggestive of a primary bone tumor with a pathologic fracture. Biopsy specimens demonstrated neoplastic mesenchymal cells producing osteoid compatible with a diagnosis of osteosarcoma. This case history report constitutes the youngest reported canine osteosarcoma.     

Zoledronic acid for the treatment of appendicular osteosarcoma in a dog

A 10-year-old male intact Corso dog was referred for lameness and for a large neoplasm affecting the right foreleg. Physical examination of the patient revealed a 5 × 5 × 3 cm mass in the distal right foreleg. Histopathology was consistent with a diagnosis of appendicular osteosarcoma. The staging process found no evidence of metastasis. Because of the large size of the patient, the owners elected to treat their dog with antiresorptive therapy. The patient was treated with an infusion of zoledronic acid every 28 days. The tumour remained stable for 16 months and the lameness of the dog greatly improved. At that time, the patient returned for evaluation of a large rapidly growing prescapular mass. Biopsy confirmed lymph node metastasis and the dog was euthanased. Zoledronic acid showed remarkable palliation in our patient and possibly anti-tumour action and warrants further investigation.