Huge myxosarcoma arising from the greater omentum in a dog

Bilateral testicular myxosarcoma in a cryptorchid dog

Myxosarcoma is a rare malignant mesenchymal neoplasm of soft tissues originating from fibroblasts. This report describes a case of bilateral myxosarcoma in a three-year-old cryptorchid dog. The animal was referred to the veterinary clinic because of the absence of testicles in the scrotum. Ultrasonography revealed two masses in the abdominal cavity with testicular echotexture. Exploratory laparotomy revealed the presence of cryptorchid testicles, and orchiectomy was recommended to treat the animal. Testicles were gray and reddish in color and enlarged with firm consistency. For histopathological analysis, testis fragments were fixed in 10% formalin and stained with hematoxylin and eosin and Alcian blue. Immunohistochemistry was performed using the following primary antibodies:1A4, HHF35, desmin, glial fibrillary acidic protein, CD31, S-100, vimentin, and Ki-67. Histopathological evaluation revealed the proliferation of fusiform and round cells associated with extensive areas of myxoid matrix. Neoplasms featured multinucleated giant cells, pleomorphism, karyomegaly, nuclear hyperchromasia, anisokaryosis, mitoses, and necrosis, with coarse chromatin and prominent nucleoli. Immunohistochemical analysis of vimentin- and the Alcian blue-positive cells confirmed the diagnosis of myxosarcoma. A high mitotic count and Ki-67 proliferative index suggests this myxosarcoma had a high degree of malignancy. To the best of our knowledge, this is the first case report of bilateral testicular myxosarcoma in a cryptorchid animal.

Metronomic chemotherapy: bridging theory to clinical application in canine and feline oncology

Veterinary oncology has experienced significant evolution over the last few decades, with chemotherapy being currently applied to several neoplasms with therapeutic success. Traditionally, chemotherapy protocols are based on classic cytostatic drugs under the concept of maximum tolerated dose (MTD), which has been associated with a greater risk of toxicity and resistance. Thus, new therapeutic alternatives have emerged, such as metronomic chemotherapy (MC), introducing a new paradigm in cancer treatment. MC consists of administering low doses of chemotherapy drugs continuously over a long period of time, modulating the tumour microenvironment (TME) due to the combination of cytotoxic, antiangiogenic and immunomodulatory effects. This multi-targeted therapy has been described as a treatment option in several canine and feline cancers since 2007, with positive results already published in the literature, particularly in mammary carcinomas and soft tissue sarcomas in dogs. The aim of this review article is to describe the current knowledge about the use of MC in small animal oncology, with emphasis on its mechanisms of action, the most commonly used drugs and clinical outcome.

Retroperitoneal myxosarcoma in a cat

This report details a retroperitoneal myxosarcoma in a cat that exhibited extremely aggressive biological behavior. An exploratory midline celiotomy revealed a left-sided retroperitoneal mass firmly adhered to the hypaxial musculature. Histopathological evaluation identified the mass as a myxosarcoma. Following surgical excision, the mass rapidly recurred within 6 weeks after surgery.

Computed tomographic appearance of sialoceles in 12 dogs

Published findings on the computed tomographic (CT) appearance of sialoceles are limited to brief descriptions from reported cases in eight dogs and one cat. The authors have seen sialoceles with CT characteristics that are not consistent with these previous reports. The purpose of this multicenter, retrospective, descriptive, case series study was to provide more detailed descriptions of the CT appearance of confirmed sialoceles in dogs. Dogs over a 10-year period with cytologically or histologically confirmed sialoceles and pre- and postcontrast CT studies of the head were included. Multiple qualitative and quantitative features were described for each sialocele with histological correlation. Twelve dogs with a total of 13 sialoceles were identified, including: seven cervical sialoceles, three complex (combined cervical and sublingual) sialoceles, two sublingual sialoceles, and one zygomatic sialocele. All sialoceles were characterized by fluid attenuating, non-contrast enhancing contents (median 18.5 HU) and soft tissue attenuating, contrast-enhancing walls. The external margins of all sialocele walls were smooth; however, the internal margins in six sialoceles were irregular with poorly defined nodular to frond-like protrusions. Mineralized foci of variable size (range < 1 mm to 4.8 mm) and attenuation (range 119 to 1253 HU) were present in seven sialoceles and histologically identified as sialoliths (three sialoceles) and osseous metaplasia (two sialoceles). A unique finding in the sialoceles in this study was the presence of intraluminal nodular to frond-like protrusions arising from the wall. This study also reports the CT appearance of cervical and complex sialoceles and sialocele mineralizations.