Histologically ameloblastoma showed various forms of metaplastic changes. Evidence of mucous cells is a rare finding and only 9 cases were reported. We present a case of 80 year old male suffered from mandibular swelling for five years duration diagnosed as mucous ameloblastoma. Histopathological examination revealed a lot of mucous pools within the growth, a thin fibrous capsule surrounding the mass and a direct connection between growth islands and oral mucosa. This case highlights the features of rare type of ameloblastoma.2014) seeking help and treatment because the mass became larger and start to interfere with eating and speaking. On the presentation, the patient had extensive right side mandibular expansion; measuring 7X5 cm ( Figure 1A). There was no paresthesia of the mandibular nerve and no trismus. The swelling exhibited diffuse margins and was painless and do not adhere to the overlying skin.Intra orally, there was diffused swelling extending in an edentulous area from the distal surface of the mandibular right canine to the ramus anterio-posteriorly obliterating the right buccal vestibule. The central area of the overlying mucosa showed large deep necrosis, the remaining mucosa stretched and erythematous ( Figure 1E). There was no lymph node palpable in the neck.Orthopantomography and CT examination revealed a large, welldefined unilocular radiolucency with a scalloped border and central septa. It extends from mandibular right edentulous premolar area to the ramus ( Figure 1B and 1C).A diagnosis of ameloblastoma was considered depending on the clinical, radiographic, and previous histopathological report of the lesion. Subsequently, it was removed by surgical excision as an en bloc resection (hemi mandibulectomy, Figure 1D), and the surgical specimen submitted for histologic examination.Macroscopically, the surgical specimen is the right half of the mandible (from midline to the condyle). Only anterior teeth were present. The specimen measured 12X9 cm, (including the condyle head). The mass was grayish-white in color, rubbery with a smooth surface and was well separated from the bone at posterior border, fixed in formalin. The specimen sliced, and several samples were taken for histologic examination (one from the anterior bony margins). The cut surface showed nodular white-yellowish areas and numerous focal cystic spaces of variable sizes oozing thick mucinous material. The mass was well capsulated by thin smooth continues wall ( Figure 1F).
Microscopic examination revealed numerous odontogenic