Papilliferous keratoameloblastoma - A rare entity: A case report with a review of literature

Abstract

Ameloblastoma is the most common odontogenic tumor which presents with a variety of histopathological patterns. Among all, papilliferous keratoameloblastoma (PKA) is a very rare type which is characterized by multiple epithelial cysts of varying size, which are lined by non-keratinized papilliferous epithelium which is filled with necrotic desquamated epithelial cells. In this study, we reported PKA with characteristic ameloblastic features in a 65-year-old male patient who presented with a swelling in the right mandibular body region. This is the seventh case of PKA to be reported in the English literature till date. Present case showed multicystic areas in incision biopsy which lead to misdiagnosis as calcifying odontogenic cyst with adenomatoid odontogenic tumor, but in excision biopsy which turned out to be papilliferous keratoameloblastoma, further in this paper we had discussed all the areas which lead to misdiagnosis of calcifying odontogenic cyst with adenomatoid odontogenic tumor. In outlook, more cases will put an insight to the behavioral aspects of this rare histological type of ameloblastoma.

Keywords: Adenomatoid odontogenic tumor; ameloblastoma; calcifying odontogenic cyst; papilliferous keratoameloblastoma.

Figure 1

Clinical photograph showing diffuse swelling from midline to the right side of the mandible causing facial asymmetry

Figure 2

Clinical photograph showing diffuse swelling on the edentulous alveolar ridge extending from the distal aspect of 31 to the mesial aspect of 47

Figure 3

(a) Orthopantomograph showing multilocular radiolucency extending from 33 to 46 region, with intact lower border of mandible with root resorption of 31 and 32. (b) Occlusal radiograph showing buccal cortical expansion with internal multilocular radiolucency

Figure 4

(a) Photomicrograph showing cystic lining with ghost cells (black arrows) (H&E, ×10). (b) Photomicrograph of the same section showing duct like structures (black arrow) with focal rosette like pattern (red arrow) (H&E, ×10)

Figure 5

(a) Photomicrograph showing cystic space lined by a keratinized stratified squamous epithelium which is made up of 4–5 cells in thickness with papillary projections into the cystic lumen (red arrow) and into connective tissue (black arrow) (H&E, ×10). (b) Photomicrography showing abundant desquamated keratin bodies showing faint nuclear outline (H&E, ×40). (c-e) Photomicrography showing follicle with papillary projections into the lumen (red arrow) and into the connective tissue (black arrow) (H&E, ×20)

Figure 6

Photomicrography showing a plexiform appearance of papillary projection (black arrow) arising from the cystic lining extending into the connective tissue

Figure 7

Photomicrograph showing tumor islands with squamous metaplasia (H&E, ×20)

Figure 8

Photomicrograph showing tumor cells arranged in plexiform form pattern (H&E, ×20)