Primary Paranasal Maxillary Hematoma: Clinical Characteristics, Diagnosis and Surgical Treatment
Authors: De Oliveira e Oliveira Natalia Franco , Martinez Matheus Murilo , Jaramilo Fernando Mosquera , Bittar Maurício José , Guilarde Pacheco José Carlos , Correia da Silva Luís Cláudio Lopes , Do Valle de Zoppa André Luis , Corrêa Rodrigo Romero 
Published: July 2019

Background: The equine paranasal sinus have a complex anatomy and large compartiments. For this reason, deseases that affect these structures may develop for long periods before the animal show any clinical signs, making it difficult to stablish a definitive diagnosis and institute an adequate treatment.  Usually, maxillary hematomas reports come from progression of ethmoidal hematomas, and the descriptions of primary maxillary hematomas are rare. This study aims to report the clinical features, diagnosis and treatment of a case of a maxillary hematoma not associated with ethmoidal turbinates.Case: An 8-year-old male horse, Mangalarga Paulista, was referred to the Centro de Apoio ao Ensino e Pesquisa FMVZ-USP with history of nasal bleeding for over a year. The animal presented deformity on the right side of the face, with significant volume increase on the maxillary bone region and dull sound at percussion, in addition to great painfull sensibility when palpated. The right nare had no airflow, suggesting complete obstruction of the right nasal cavity. In order to better evaluate, endoscopic and radiographic exams were performed. At the radiographic exam, in ventrodorsal projection, it was observed an increase of volume and radiopacity, occupying the right antimer of the nasal cavity, with left nasal septum deviation. In the right dorsoventral oblique projection, it was observed the filling of the rostral and caudal maxillary sinus with the content radiopacity as previously described. At endoscopy exam of the right nasal cavity, it was observed a rounded greenish structure on the middle meatus The diagnosis of maxillary paranasal sinus cist was suggested and surgical removal, through maxillary sinusotomy was recommended. During the surgical procedure, it was noted that the structure previously observed, was not a cavitary organization filled with liquid, but a deorganized, dark and friable mass, like a hematoma.   A fragment was sent to histopathological evaluation, which revealed the presence of intact eythrocytes interspersed by fibrilar eosinophilic material (fibrin). There were no indications of an infectious or neoplastic process. The diagnosis of maxillary hematoma was concluded. Forty days after admission, the patient had no surgical complications and showed adequate respiratory flow, at which point the animal was discharged.Discussion: Primary maxillary hematomas are rare on equines. Although benign, it has destructives and expansives characteristics, and for this reason, it can be confused with malignant tumor formation. It has unknown ethiology, and the clinical signs observed are diverse and non specific, which makes it hard to stablish a definitive diagnosis based only on the clinical manifestations of the animal. In this particular case presented, the diagnosis was defined from the hitophatological examination. Initially the image exams (radiography and endoscopy) were usefull to stablish differential diagnosis, as well as the extention of the sinus mass. The surgery was performed with the animal on quadrupedal position, under sedation and local anethesia, in order to dimish haemorrhage occurance during the procedure. This paper describes a primary maxillary hematoma on a horse, characterizing it as to the clinical and pathological manifestations, as well as its surgical treatment. Although rare descriptions and with non specific clinical signs, it is suggested that its occurrence is superior to that described in the literature.