Rhabdomyosarcoma of the urethra in a dog

This paper describes the clinical and pathological features of a case where a rhabdomyosarcoma developed in the pelvic urethra of a 12-month-old German Shepherd. The literature on rhabdomyosarcoma involving the canine urinary tract is reviewed.     

Dermoid cyst in the tongue of a dog

A German Shepherd Dog presented with recurrent intermandibular and intralingual swelling. Cytological and microbiological findings on fluid aspirated from the mass were consistent with an infected cyst lined by epithelium. The sinus was explored and an epithelium-lined cystic structure was extirpated from the frenulum and body of the tongue. This structure was diagnosed histologically as a dermoid cyst.     

Multifocal rhabdomyosarcomas within the tongue and oral cavity of a dog

A 10-year-old terrier crossbreed presented with a change in bark intonation of 3-4 month's duration and pronounced panting. Four variably sized masses were observed within the oral cavity. The largest mass was located within the parenchyma at the caudal region of the tongue. Others were located on the left arytenoid, within the soft palate, and in the oropharynx above the soft palate. Histopathologic specimens consisted of large round to polygonal cells occasionally containing multiple nuclei and rare faint cytoplasmic cross striations. Staining was weakly positive with periodic acid-Schiff. Immunocytochemistry was strongly diffusely positive for muscle-specific actin, myoglobin, and desmin and scattered positive for S-100 and vimentin. Phosphotungstic acid-hematoxylin staining enhanced cytoplasmic cross striations. The cytoplasm of all neoplastic cells was filled with mitochondria on electron microscopy. The final diagnosis was multifocal/metastatic rhabdomyosarcoma.     

Immunohistochemical study of a granular cell tumor on the tongue of a dog

Abstract: A granular cell tumor (GCT; myoblastoma) was diagnosed on the tongue of a 12-year-old English Pointer with clinical signs of mild oral dysphagia. The diagnosis was confirmed by histopathologic examination and immunohistochemistry. The tumor was positive for S-100 protein, but also was positive for desmin, and was only weakly positive for PAS, which is unusual for GCTs. An epithelioid type of leiomyoma (leiomyo-blastoma) was considered less likely on the basis of negative staining for smooth muscle actin. Treatment consisted of surgical resection of the tumor. The animal was in excellent clinical condition 1 year after surgery. Although GCT of the tongue has been reported previously in the dog, determining the cell of origin is still problematic. Immunohistochemistry is helpful for histogenetic classification and necessary for differentiation from leiomyoblastoma.     

Granular cell myoblastoma in the tongue of a dog: A case report

A granular cell myoblastoma was found in the dorsal side of the tongue of a 9‐year‐old female mongrel Pinscher. Macroscopically the tumour was white, well circumscribed, and 1½> cm in diameter. Microscopically the tumour cells were arranged in small compact nests or cords with delicate, poorly vascularized collagen bundles in between. A cinar structures were found, also a few mitotic figures were present. Cytoplasmic granules showed a positive periodic acid Schiff reaction. Ultrastructural features included indented nuclei and small‐sized vesicular cytoplasmic granules.

The histogenesis of the neoplasm remains uncertain.     

The management of total tongue avulsion in a dog: a case report

A 17-month old Dobermann Pinscher bitch was presented with a self-induced, total avulsion of the tongue. Clinical signs of haemorrhagic shock were present. An inability to swallow led to rapid and progressive dehydration and weight loss. Management was initially directed at the correction of haemorrhagic shock, and then at the maintenance of fluid and energy balance while the tongue root healed by secondary intention. Aggressive parenteral feeding and hydration via a pharyngostomy tube resulted in stabilization of body weight. The dog has since gained weight and can maintain adequate food and water intake. Solid food is taken into the mouth and swallowed with minimal difficulty, although drinking is accompanied by some spillage.     

Rhabdomyosarcoma in a Silver Carp

Rhabdomyosarcoma is a primitive neoplasm that originates from skeletal muscle progenitor cells. In a routine inspection of a cyprinid farm in southwestern Iran, an approximately 2-year-old female Silver Carp was observed to have a raised mass located on the dorsolateral surface just caudal to the head. Macroscopic examination revealed a firm irregular fleshy pink mass (5 × 4 cm, depth = 3 cm) that appeared to arise from the subcutaneous musculature. Histologic sections were prepared using routine methods and separate sections were stained with hematoxylin-eosin and Massons’ trichrome. Microscopically, the tumor mass was composed of spindle cells that were densely packed and arranged in long interwoven bundles. The nuclei were vesicular and oval to elongated or cigar-shaped. Nuclear pleomorphism and multinucleate tumor giant cells were clearly evident. The neoplastic cell cytoplasm was eosinophilic with indistinct cell margins, and clear cross striations were observed in fibrils. The striated fibrils stained diffusely red with Masson’s trichrome. This account represents the first reported occurrence of rhabdomyosarcoma in Silver Carp Hypophthalmichthys molitrix.

Received July 10, 2015; accepted February 4, 2016     

Tongue rotation for reconstruction after rostral hemiglossectomy for excision of a liposarcoma of the rostral quadrant of the tongue in a dog

A 15-year-old female beagle dog was presented for a lingual liposarcoma. Full staging of the disease did not show any evidence of metastasis. A tongue rotation for reconstruction after rostral hemiglossectomy was performed after removal of the mass. This surgical technique may be useful in tongue reconstruction after trauma or tumor excision.     

Rhabdomyosarcoma in 8 horses

This multi-institutional report describes 8 cases of rhabdomyosarcoma in horses. Four neoplasms were in the tongue and other areas of the mouth or head, 2 were in the abdominal wall, and 1 each was in right shoulder muscles and heart. Four rhabdomyosarcomas that were less than 10 cm in diameter were treated by surgical excision or radiation with no recurrence. Two neoplasms greater than 10 cm in diameter in the abdominal wall and the right shoulder were considered inoperable and led to decisions to euthanize the horses. Two neoplasms were incidental findings at necropsy. All the neoplasms were classified as embryonal except for 1 pleomorphic rhabdomyosarcoma. These 8 cases were evaluated with 9 published case reports of equine rhabdomyosarcoma. For all cases, the most common sites were limb muscles (5/17) and tongue (4/17). Metastasis was reported in 4 of the previously published cases; none was found in this study.     

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.     

Rhabdomyosarcoma (botryoid sarcoma) of the urinary bladder in a Maltese

A urinary bladder tumour was diagnosed in a two-year-old female Maltese with haematuria and pollakiuria on the basis of ultrasonography and pneumocystography findings. The mass was resected, and the bladder was preserved at surgery. Histological and immunohistochemical examination confirmed the tumour to be a rhabdomyosarcoma, which has rarely been reported in small breeds of dog. There was no recurrence of the tumour at the original site in the urinary bladder two months later, when the dog died due to metastasis to the liver. This is believed to be the first report of bladder rhabdomyosarcoma in a Maltese.     

Rhabdomyosarcoma in a ferret (Mustela putorius furo)

A 5-year-old spayed male ferret showed a subcutaneous mass in the right lateral thoracic wall. Microscopic examination revealed that the neoplasm had proliferated in the subcutis with infiltration into the surrounding tissues. A packed bundle of large polymorphic neoplastic cells, containing abundant eosinophilic cytoplasm and a round to ovoid, occasionally bizarre nucleus, were arranged interwoven. The neoplasm had metastasized to the right axillary lymph node. The neoplastic cells were intensively positive for vimentin, desmin and myoglobin. Skeletal muscle type creatine phosphokinase-positive granules were detected in the cytoplasm. Ultrastructurally, various amounts of disorganized myofibrils with focal density resembling the Z-band were shown in the cytoplasm of the neoplastic cells. The neoplasia was diagnosed as rhabdomyosarcoma.     

Vascular hamartoma in the tongue of a horse

Hamartoma is defined as a benign tumor-like nodule composed of an overgrowth of mature cells and tissues that normally occur in the affected part but with disorganization. Vascular hamartomas are defined as disorganized and excessive proliferations of vascular tissue. Most vascular hamartomas are present at birth or during early infancy and are considered developmental lesions rather than true neoplasms. Vascular hamartomas are rarely described in horses, and reports have been limited to the dorsal carpal region, the ovary, and the face. In this report, we describe a vascular hamartoma arising from the tongue of a 2-year-old Quarter Horse.