Primary leiomyosarcoma of the inferior vena cava in a pediatric case: a case report and literature review.

BACKGROUND: Leiomyosarcoma is classified as a soft tissue sarcoma. In adults, leiomyosarcoma is the most common malignancy affecting the vascular system; however, vascular leiomyosarcoma in children is extremely rare as most pediatric soft tissue tumors are rhabdomyosarcomas. The survival rate is very low, and incomplete resection is a poor prognostic factor. There is also a high rate of distant recurrence, with the lungs and liver being the most common sites of metastasis. There is no established effective chemotherapy, and complete surgical resection is the only potentially curative treatment for leiomyosarcoma. CASE PRESENTATION: A 15-year-old female patient with no significant medical history presented with severe upper abdominal pain and was admitted. Abdominal contrast-enhanced computed tomography and magnetic resonance imaging showed a large retroperitoneal tumor protruding into the lumen of the inferior vena cava behind the liver and multiple small nodules, and metastasis to the liver was suspected. The tumor was 6 × 4 × 5 cm in diameter, located just behind the hepatic hilar structures, and was suspected to infiltrate into the right portal vein. The tumor was diagnosed as a leiomyosarcoma through an open tumor biopsy. As the multiple liver metastases were located only in the right lobe of the liver on imaging, we performed tumor resection with right hepatectomy and replacement of the inferior vena cava (IVC). The postoperative course was uneventful; however, on postoperative day 51, distant metastatic recurrences were found in the remaining liver and right lung. The patient was immediately started on chemotherapy and trabectedin proved to be the most effective drug in the treatment regimen; however, severe side effects, such as hepatotoxicity, prevented timely administration, and the patient passed away 19 months after surgery. CONCLUSIONS: IVC resection and reconstruction combined with right hepatectomy were able to be safely performed even in a pediatric case. To improve the prognosis of leiomyosarcoma with multiple metastases, an effective treatment strategy combining surgical treatment and chemotherapy, including molecularly targeted drugs, should be established as early as possible.

New categories designated as healthcare-associated and community-associated methicillin-resistant Staphylococcus pseudintermedius in dogs.

The incidence of MRSP has been increasing, and treatment options in veterinary medicine are limited. Few previous studies of MRSP have described the relationships between the genotypes, phenotypes, and clinical backgrounds of the isolates. To gain insight into the associations between the microbiological and clinical characteristics of MRSP, we analyzed 282 Staphylococcus pseudintermedius isolates from dogs. A total of 195 (69.1%) strains were identified as mecA-positive MRSP and were classified into mainly two genotypes: SCCmec types III (II-III) (52.8%) and V (37.4%). SCCmec type III MRSP strains were significantly correlated with hospital admission and antimicrobial therapy of the dogs, and exhibited a homogeneous genotype similar to sequence type 71-MRSP, which is a globally endemic clone in dogs. In contrast, SCCmec type V MRSP strains were not highly correlated with hospital admission and antimicrobial therapy and exhibited genotypic and phenotypic heterogeneity. Properties of MRSP strains SCCmec types III and V were similar to those of HA- and CA-MRSA, respectively. Therefore, we designated these isolates carrying SCCmec types III and V as HA-MRSP and CA-MRSP, respectively. Discrimination between HA- and CA-MRSP by oxacillin MIC will provide useful information for treatment and infection control measures for canine MRSP infections.

A malignant and metastasizing feline cardiac ganglioneuroma.

In the current study, a case of a cardiac ganglioneuroma with systemic metastases in a cat is described. A 12-year-old male neutered Japanese domestic cat was brought to a veterinary hospital for dysorexia, coughing, vomiting, and diarrhea. Ultrasonography revealed a mass adjacent to the right atrium. The animal died of respiratory failure 1 month after the first visit to the hospital. At necropsy, an oval-shaped white mass 1.5 cm in diameter was observed within the right auricle. Diffusely, the right ventricle was infiltrated and thickened by the neoplastic lesion. Histologically, the mass was composed of 3 types of neoplastic cells: spindle cells, large polygonal cells, and small undifferentiated cells. Immunohistochemically, the neoplasia was positive for neuronal markers such as ßIII tubulin, S-100a, and protein gene product 9.5. Ultrastructurally, the large polygonal cells were characterized by abundant cytoplasm that included compressed Golgi cisternae and rough endoplasmic reticula and abundant intermediate filaments. A discontinuous basement membrane surrounded the spindle cells. Metastatic foci were found in the lungs, kidney, pancreas, urinary bladder, and adrenal glands. The morphological, immunohistochemical, and ultrastructural characteristics of the tumor cells were consistent with those of ganglioneuroma. The tumor was presumed to originate from the intramural parasympathetic ganglia in the right atrium.