[Adenocarcinoma of the paranasal sinuses in sheep: First case description in Morocco].

INTRODUCTION
Small ruminant sinus adenocarcinoma (ENA) is a contagious disease caused by a beta retrovirus called Enzootic Nasal Tumor Virus or ENTV. The first cases were sporadically diagnosed in Morocco in 2018. However, in the last two years, ENTV has appeared enzootic in three herds of the Sardi breed. The annual incidence varied between 5 and 20 %. Most cases involved female animals aged 15 to 42 months. The disease developed within 2 to a maximum of 6 months. Diseased animals presented with progressive weight loss and increased mortality or needed to be slaughtered. The condition associated mainly with unilateral skull deformation, serous or seromucous nasal discharge with dyspnea, and in some individuals an exophthalmos. During pathology tumor-like masses were found in the paranasal sinuses, which showed the growth of an expansive and organized epithelial neoplasm on histopathology. After an overview of the differential diagnoses that can lead to confusion with ANE, the authors investigate why the disease occurs more frequently in Morocco and particularly in the Sardi breed.