Cytopathological and ultrasonographic findings of mastocytoma in a scrotal pouch in a dog

Abstract

Mast cell tumors are the most common skin cancer in dogs. They are characterized by excessive proliferation of neoplastic mast cells. The areas of higher incidence are posterior region of the animal body, scrotum and flank. The diagnosis of mastocytoma is may have the aid of imaging tests such as ultrasonography, but it is essentially based on cytology. A dog was admitted to VETCLINIC for ultrasonographic and cytological examination of the scrotal region, because it was enlarged after orchiectomy procedure. Ultrasonographic examination revealed a heterogeneous echogenic image measuring 3.93 cm by 2.76 cm, showing regular and defined contours and with evident internal vascularity in Doppler mode suggestive of inflammatory process. In cytology, the sample of low cellularity consists of individualized round cells. Round to oval nucleus presenting coarse chromatin and sometimes evident nucleoli (1-2). Moderate to large cytoplasm with intense presence of granules of pink coloration. Intense anisocytosis and anisocariasis. Background of hemorrhagic blade with marked presence of granules, being the suggestive report, being the findings compatible with mastocytoma.