Comparative analysis of primer sets for the assessment of clonality in feline lymphomas.

Introduction: Lymphomas are among the most important and common malignant tumors in cats. Differentiating lymphomas from reactive lymphoid proliferations can be challenging, so additional tools such as clonality assessment by PCR are important in diagnosis finding. Several PCR assays have been developed to assess clonality in feline lymphomas. For T-cell lymphomas TRG (T-cell receptor gamma) genes are the preferred target whereas for B-cell lymphomas most primer sets target immunoglobulin heavy chain (IGH) genes. Here we compare commonly used diagnostic primer sets for the assessment of clonality in feline lymphomas under controlled conditions (i.e., identical sample set, PCR setup, amplicon detection system). Methods: Formalin-fixed and paraffin-embedded samples from 31 feline T-cell lymphomas, 29 B-cell lymphomas, and 11 non-neoplastic controls were analyzed by PCR combined with capillary electrophoresis. Results and discussion: We show that the combination of the primer sets published by Weiss et al. and Mochizuki et al. provided the best results for T-cell clonality, i.e., correctly assigns most populations as clonal or polyclonal. For B-cell clonality, the combination of the primer sets by Mochizuki et al. and Rout et al. gave the best results when omitting the Kde gene rearrangement due to its low specificity. This study rigorously evaluated various primer sets under uniform experimental conditions to improve accuracy of lymphoma diagnostic and provides a recommendation for achieving the highest diagnostic precision in lymphoma clonality analysis.

[Myxosarcoma in the cervical region in a teddy bear hamster (Mesocricetus auratus)]. / Myxosarkom in der Halsregion eines Teddy-Hamsters (Mesocricetus auratus).

This case report describes a rare case of a myxosarcoma in a 1-year-old teddy bear hamster presenting with a mass in the cervical region. The fine-needle aspiration cytology revealed high numbers of pleomorphic spindle-shaped cells found in a viscous mucinous background. The presumptive cytological diagnosis was malignant spindle cell neoplasia based on marked criteria of malignancy of the mesenchymal cell population. The abundant matrix in the background was suggestive of a myxosarcoma. The hamster died during surgery and a necropsy was performed. Histopathology was in complete agreement with the cytological report. Immunohistochemistry revealed the tumour to be vimentin positive with alcian-blue positive matrix and confirmed the presumptive diagnosis of a myxosarcoma. This case shows that fine-needle aspiration cytology can be utilized as a minimally invasive diagnostic tool in small mammals to classify mass lesions. However, so far little is known about the biological behaviour of myxosarcoma in the hamster as case descriptions are rare.

Histological and Immunohistochemical Characterization of Vascular Alterations in Meninges of Cats Infected with Gurltia paralysans.

Gurltia paralysans, a metastrongyloid nematode, parasitizes in meningeal vessels in the thoracolumbar spinal cord of cats in South America and causes progressive paraparesis. Recently, the first report outside of South America described gurltiosis in a cat in Spain. As this parasitic disease has so far been largely neglected, especially outside of South America, the aim of the present case study was to add knowledge to the histologic and immunohistochemical characterization of central nervous lesions. To this purpose, formalin-fixed and paraffin-embedded (FFPE) tissue samples from the spinal cord and brain of five cats affected by clinical signs caused by Gurltia paralysans and of three control cats without CNS lesions were histopathologically examined using hematoxylin and eosin stain (HE), Elastica van Gieson stain, as well as periodic acid-Schiff (PAS) reaction. Moreover, immuno- histochemistry for alpha smooth muscle actin and Factor VIII-related antigen were performed to characterize vascular lesions. Lesions were consistent with previous descriptions and were mainly located in the spinal cord and consisted of chronic suppurative or lymphoplasmahistiocytic meningi tis as well as suppurative vasculitis, congestion and varicosis of meningeal veins. In view of the recent detection of this parasite in Europe and the increasing inner-European transport of rescued domestic cats, veterinarians in Europe should be aware of the clinical and pathomorphological presentation of this disease.