The mast is a rare feline neoplasia, representing three percent of all cutaneous neoplasia. The mast also has a visceral presentation with hemolymph or gastrointestinal involvement. There are two forms of this mast, the histiocytic and, the most common, mastocytic form. There is no sexual predisposing. All mast has to be considered potentially malignant. The biologic comportment and the location of the mast in cats are controversial, however, generally, dermoepidermal or subcutaneous mass, multiple or lonely affecting the head and the neck are observed. Felines with the mastocytic form generally presents more than four years-old, have lonely mass and no breed predisposing. On histiocytic form, the Siamese are the most affected breed with less than four years-old and with multiple miliary masses that can regress spontaneously. Anorexia, emesis, hematemesis and melena can be observed if gastroduodenal ulcer is present. The suspected diagnosis is based on anamnesis providing the evaluation time and growing speed, on physicals exams providing the location, the number of existing masses, and the presence of metastasis signals like the size of lymph nodes, splenomegaly and/or hepatomegaly. The definitive diagnosis usually is done with Fine Needle Aspiration Cytology (FNAC).

Surgical excision with wide safety margin is indicated on lonely mass cases without metastasis. There are controversies to the conservative treatment and the use of systemic or dermatologic intralesional chemotherapy and corticoids. Chemotherapy is recommended on spread mast cases. Two cases of feline mast were attended at the Veterinary Hospital "Professor Ricardo Alexandre Hippler" at the University Center of Vila Velha with one year of interval. The first was a mongrel, male, with two and a half years-old with the history of alopecia and pruritus nodes distributed on the head and the right pelvic member when the animal has 6 months of age. Well differentiated mastocytic mast was concluded at histopathology. Hydrocortisone intralesional was prescribed and after that the animal was routed to surgery. The second was a ten years-old male Siamese with alopecic dermoepidermal nodular lesion with 0.4cm of length and 0.3cm of width presenting gummy aspect on the proximal region of tail ventral face observed since one week ago to the consultation. Well differentiated mast was diagnosed at FNAC. Surgical removal and/or chemotherapy are not prescribed to the patient because he was a chronic renal failure patient. Until now both animals are in a good overall health.