Contiguous enlarged dental follicles with histologic features resembling the WHO type of odontogenic fibroma.

Defective odontogenesis and/or retarded eruption of teeth can be associated with histologic features akin to odontogenic fibroma in the dental follicles. Unerupted mandibular premolar and molar teeth of a 24-year-old man were surgically exposed, yet the teeth failed to erupt. About a year and a half later, radiographs indicated further enlargement of the follicle of the premolar, and both teeth were subsequently surgically removed. Histologically, the follicles were composed of mature collagenous tissue among which epithelial islands and numerous clusters of calcified bodies were present. Indirect immunofluorescence showed positive staining for type I and type III collagen, which exhibited a sparse distribution, but not for the aminoterminal propeptide of type III procollagen. The hamartomatous nature of the lesions is discussed with emphasis on their histologic resemblance to the WHO type of odontogenic fibroma.