Les lésions du complexe fibrosarcome félin : étude histopathologique et immunohistochimique

L'étude histologique et immunohistochimique de 300 néoformations du complexe fibrosarcome félin (CFF) révèle une grande diversité lésionnelle tumorale (type tumoral, degré de différenciation, nature des cellules géantes multinucléées parfois présentes et expression des marqueurs Ki-67 et p53), l'association fréquente de tumeurs et de lésions non tumorales (panniculite, fibromatose) et l'existence d'une progression de certaines lésions non tumorales vers la tumorisation. La notion de CFF pourrait être reconsidérée et inclure d'autres tumeurs que les sarcomes à cellules fusiformes. Par ailleurs, l'homogénéisation du diagnostic histologique des lésions du CFF, mentionnant nature, localisation et taille de la tumeur, degré d'infiltration, critères histologiques, cytologiques et immunohistochimiques de différenciation, nature des cellules géantes, lésions associées, index de prolifération, expression de p53 et examen des marges, semble indispensable pour toute étude ultérieure à visée comparative

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

Background: Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions. Results: A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Conclusions: The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine

Les lésions du complexe fibrosarcome félin (étude histopathologique et immunohistochimique)

L'étude histologique et immunohistochimique de 300 néoformations du complexe fibrosarcome félin (CFF) révèle une grande diversité lésionnelle tumorale (type tumoral, degré de différenciation, nature des cellules géantes multinucléées parfois présentes et expression des marqueurs Ki-67 et p53), l'association fréquente de tumeurs et de lésions non tumorales (panniculite, fibromatose) et l'existence d'une progression de certaines lésions non tumorales vers la tumorisation. La notion de CFF pourrait être reconsidérée et inclure d'autres tumeurs que les sarcomes à cellules fusiformes. Par ailleurs, l'homogénéisation du diagnostic histologique des lésions du CFF, mentionnant nature, localisation et taille de la tumeur, degré d'infiltration, critères histologiques, cytologiques et immunohistochimiques de différenciation, nature des cellules géantes, lésions associées, index de prolifération, expression de p53 et examen des marges, semble indispensable pour toute étude ultérieure à visée comparative.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

Multinodular Malignant Cutaneous Mast Cell Tumor in a Horse With Generalized Pruritus and Reactive Fibrosis: A Case Report

International audienceMast cell tumor (MCT) has long been considered as an uncommon neoplasm in horses. Cytological and behavioral evidence of its malignancy is usually lacking, and only a few reports have described MCT displaying malignant behavior. An 18-year-old Friesian stallion presented with a one-year history of intermittent and progressive skin lesions on the left forelimb associated with intense, generalized pruritus and apathy temporarily responsive to glucocorticoids and antibiotics. The horse was alert and responsive with poor body condition and marked generalized pruritus. The left forelimb was markedly enlarged and surrounded by numerous firm 2- to 20-cm masses that were ulcerated and focally necrotic. A 7-cm round firm mass was observed on the left dorsal neck. Dermatological examination revealed generalized moth-eaten alopecia and scaling with erosions and ulcers secondary to pruritus. A direct skin smear from the affected leg showed severe eosinophilic inflammation and neutrophilic inflammation with pleomorphic bacteria. Histopathology of the skin and biopsies of the underlying tissues revealed an abundant population of atypical mast cells consistent with a malignant MCT. The horse was euthanized and necropsy revealed a marked fibrous reaction on longitudinal sections of the affected limb, and the tumor could be detected on only a few histological slides. Diagnosis of equine MCT can be challenging because of the massive accompanying fibrous reaction. Mast cell tumor should be suspected in the presence of eosinophilic infiltration of the affected tissue and in cases of generalized pruritus not attributable to other causes