Keratoameloblastoma: Report of a rare variant with review of literature

Abstract

Ameloblastoma has intrigued clinicians as well as pathologists due to its diverse clinical behavior and histomorphologic presentations. Keratoameloblastoma is a rare histologic sub type, characterized by extensive keratin formation within ameloblastic epithelium, with only a handful number of cases described in the literature. Here, we report a case of this uncommon sub type of ameloblastoma in a young female patient presenting as an extensive lesion in mandibular ramus area. The radiological and fine needle aspiration findings suggested of a keratinizing cystic lesion and incisional biopsy showed features of ameloblastoma. Patient underwent segmental mandibulectomy and histological examination of excisional specimen revealed features of ameloblastoma with abundant keratinization leading to a diagnosis of keratoameloblastoma. The diagnostic pitfalls related with the lesion have been discussed along with a short review of the literature.

Keywords: Ameloblastoma; fine needle aspiration; keratoameloblastoma; odontogenic keratocyst; papilliferous keratoameloblastoma.

Figure 1

Clinical photograph showing diffuse swelling of the right side of the face causing facial asymmetry

Figure 2

Orthopantomograph showing large unilocular radiolucent lesion on the right mandibular ramus involving the coronoid process. Well-defined sclerotic margins and sparing of the condylar process can be noted

Figure 3

Photomicrograph showing fine needle aspiration cytology from the lesion revealing epithelial squames along with numerous nucleated and anucleate keratin flakes in a background of necrosis and debris (PAP, ×400)

Figure 4

Photomicrograph showing proliferation of odontogenic epithelium in sheets and broad ribbons. Note the scanty loose stroma with cystic degeneration (H and E, ×100)

Figure 5

Photomicrograph showing areas of squamous metaplasia and keratin pearl formation (H and E, ×200)

Figure 6

Photomicrograph showing central cystic degeneration in ameloblastic follicle leading to the formation of keratin filled cyst (H and E, ×200)

Figure 7

Photomicrograph showing keratin arranged in concentric lamellated flakes resembling Pacinian corpuscles (H and E, ×400)