A Case of Scrotal Leiomyosarcoma in a Dog

Abstract

A CASE OF SCROTAL LEIOMYOSARCOMA IN A DOG E. Laloy, S. Chateau-Joubert, M. El Mrini, F. Rakotovao, M. Carlus, E. Reyes-Gomez, V. Delfosse and N. Cordonnier National Veterinary School of Alfort, France Introduction: Scrotal smooth muscle tumours are uncommon in man. They arise from the tunica dartos of the scrotum. They have not been reported in animals. Materials and Methods: A 6-year-old male shar pei dog presented with a single 1-cm diameter mass arising from the left scrotum. Surgical excision was performed and the nodule was fixed in 10% neutral buffered formalin, processed routinely and embedded in paraffin wax. Sections were stained with haematoxylin and eosin. Several sections were subjected to immunohistochemistry. Results: The neoplasm was well circumscribed, but unencapsulated. It showed multifocal contiguity with the dartos smooth muscle bundles. It comprised of short interlacing bundles of plump spindle cells within minimal collagenous stroma. The neoplastic cells had abundant eosinophilic cytoplasm and oval to elongated nuclei. Moderate anisokaryosis and anisocytosis were seen. There were seven mitotic figures per 10 high-power fields ( 40). Small focal areas of necrosis were present. The neoplastic cells were positive for vimentin and smooth muscle actin, while they were negative for melan A, glial fibrillary acidic protein (GFAP) and S100. A few cells were positive for desmin. Conclusions: The histological and immunohistochemical findings were most consistent with a scrotal leiomyosarcoma. This is the first report of scrotal leiomyosarcoma in a dog. MESOTELIOMA OF THE TUNICA VAGINALIS OF THE TESTIS IN THE DOG: AN UNCOMMON NEOPLASM WITH MALIGNANT BEHAVIOUR G.A. Ram irez*, A. Su arez-Bonnet y, A. Espinosa-de-los-Monteros y, J. Altimira* and M. Vilafranca* *HISTOVET Laboratory and yLas Palmas de Gran Canaria University, Spain Introduction: Mesotheliomas of the tunica vaginalis testis are extremely rare. The aim of this work is to describe the clinical, histological and immunohistochemical features as well as the clinical outcome of this neoplasm in the dog. Materials and Methods: Our records were reviewed for dogs with a diagnosis of testicular mesothelioma made between 1995 and 2011. Clinical histories and follow-up information were obtained from referring clinicians. Diagnoses were confirmed by re-review of paraffin wax-embedded specimens. Immunohistochemistry was also performed with a panel of antibodies including cytokeratins, vimentin and CEA. Results: Cases were presented as swelling of the scrotum. Ultrasonography revealed heterogeneous and irregular masses with a mixed echogenicity; anechoic effusion surrounding the affected testicles (hydrocele) was also common. Gross examination often revealed firm, polypoid or papillary, yellow to white masses with a solid cut surface. The tunica vaginalis was thickened, studded with nodules of varying size, and diffusely calcified in one case. Invasion of the spermatic cord was common. Microscopically, the tumours had epithelial features with papillary, tubulopapillary or solid patterns and consistently expressed cytokeratins and vimentin. Post-operative recovery was always uneventful, but worsening of general health was reported in a period of!7 months. Necropsy examination, when performed, confirmed abdominal metastatic disease. Conclusions: Mesothelioma of the tunica vaginalis testis in the dog is a rare malignant neoplasm with an aggressive behaviour and poor outcome.