Ameloblastomas with pronounced desmoplasia

Abstract

Ameloblastomas are uncommon epithelial tumors of the jaws comprising approximately 1% of all odontogenic cysts and tumors.’ Although most are microscopically benign and lack cytologic atypia, they are generally considered to be locally aggressive and destructive, exhibiting a high rate of recurrence. In spite of its apparent rarity, several large series describing a thorough clinical statistical analysis have been reported.‘,2 Over 80% of all ameloblastomas occur in the mandible, the vast majority being located in the molar-ramus region. The average age of patients is approximately 39 years, and there is essentially no sex prediliction. Radiographically, the ameloblastoma may vary in size and configuration from a small, well-circumscribed unilocular radiolucency to a large multilocular radiolucency. Many are associated with unerupted teeth and resemble dentigerous cysts. The most common clinical finding is a nontender enlargement that, in spite of a relatively slow rate of growth, may reach enormous size.3 Microscopically, the classic ameloblastoma consists of islands, nests, and cords of odontogenic epithelium rimmed by columnar cells resembling ameloblasts. The center of these epithelial structures contains loosely arranged spindleor stellateshaped cells resembling the stellate reticulum of a developing tooth. The surrounding fibrous connective tissue stroma is composed of mature collagen.