Fibroma, Dermis and Subcutis, Rat

Fibromas are described as well-circumscribed, firm, grayish-white, dermal or subcutaneous masses with a whorled appearance on cut section. They are usually focal, flat or raised masses and can vary from less than 1 cm to several centimeters in size. Some of the fibromas may become ulcerated and/or infected. They are usually mobile in relation to the epidermis and underlying tissue. Fibromas and fibrosarcomas can occur within the same animal (Bogovski 1979; Greaves and Faccini 1984; Stannard and Pulley 1978; Zackheim 1973).