Papilliferous Keratoameloblastoma: An Extremely Rare Case Report

Odontogenic tumors develop in the jaw bones from the odontogenic tissue-oral epithelium in tooth germ, enamel organ, dental papilla, reduced enamel epithelium, remnants of Hertwig’s root sheath or dental lamina, and so forth. Hence, a bewildering variety of tumors are encountered in the maxilla and mandible. Ameloblastoma is the second most common odontogenic neoplasm after odontomes, and it has numerous clinical and histologic variants. We report a very rare histologic variant: the papilliferous keratoameloblastoma which is the fifth reported case in the English literature. 1. Introduction Ameloblastoma is a true neoplasm of enamel organ-type, tissue which does not undergo differentiation to the point of enamel formation. It has been described very aptly by Robinson as being a tumor that is usually “unicentric, nonfunctional, intermittent in growth, anatomically benign, and clinically persistent” [1]. Ameloblastoma is the most common odontogenic epithelial tumor of the jaw bones [2], and it is characterized by a substantial number of histologic subtypes [3]. Recognition of the various histomorphic patterns is thus only of diagnostic significance and is especially important for histopathologists, despite the fact that they are generally considered to be locally aggressive and destructive, exhibiting various rates of recurrences. Variations of ameloblastoma that exhibit keratinization in their parenchyma are the Acanthomatous ameloblastoma, Keratoameloblastoma (KA), and Papilliferous Keratoameloblastoma (PKA). Of these, Keratoameloblastoma and Papilliferous Keratoameloblastoma are extremely rare tumors, and despite the similarity of the names, Keratoameloblastoma and Papilliferous Keratoameloblastoma are distinct morphologically [4]. Pindborg [5] first proposed the term “Keratoameloblastoma” for use as a diagnostic entity. In his 1970 report, Pindborg described a histologic variant of ameloblastoma, which he termed Papilliferous Keratoameloblastoma. Subsequently, 3 additional cases of ameloblastoma with a Papilliferous component were reported in 1991 [3], 1994 [6], and 2002 [7], bringing the number of case reports of PKA in the English Language literature to four. We report a case of Papilliferous Keratoameloblastoma which is the 5th case to document in the English literature. 2. Case Report A 46-year male patient reported to the dental hospital with the complaint of swelling in the right side of the lower jaw since 1 year. The swelling progressed slowly to the present side with no history of toothache, and the past medical history is noncontributory. On