Desmoplastic ameloblastoma is a rare variant of ameloblastoma. Up until now, less than patients have been reported in the literature. We report a case of desmoplastic ameloblastoma in a year-old female with a painless swelling in the left anterior maxillary region. Fine needle aspiration yielded no fluid.
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Metrics details. The tumor resembles benign fibro-osseous lesion for being frequently occurring in the anterior region of jaws as a mixed radiopaque-radiolucent lesion. We present a case of DA in a year-old female with a painless swelling in the anterior region of mandible. No fluid was evident on fine needle aspiration. A mixed lesion with multilocular appearance was evident on both panoramic radiographs as well as computed tomography scan.
An incisional biopsy confirmed it to be a case of desmoplastic ameloblastoma. Segmental mandibulectomy was performed from teeth 35 to The patient is on routine follow-up and is currently free of ailment. The present case deserves emphasis because of its unfamiliar appearance, potentially aggressive nature and deceptive radiologic appearance maximizing the chances of misdiagnosis. Ameloblastoma is the second most common tumor, only next to odontoma, has its origin from the odontogenic epithelium.
The tumor is considered benign despite of its locally invasive nature. The follicular and plexiform varieties of ameloblastoma are most common, followed by the acanthomatous and granular cell types.
Less frequent cellular variants of ameloblastoma are desmoplastic ameloblastoma, clear cell ameloblastoma, basal cell ameloblastoma, keratoameloblastoma, and unicystic ameloblastoma [ 1 , 2 ].
Ameloblastomas of 0. Desmoplastic ameloblastoma differs from other variants of ameloblastoma in that it is more frequently seen in the anterior region of jaw and its mixed radiolucent radio-opaque appearance is often more representative of a fibro-osseous lesion [ 3 ]. Histologically, desmoplastic ameloblastoma is characterized by extensive stromal desmoplasia, dense collagenization with highly variable odontogenic epithelium islands and cords of various sizes.
Sun et al. The scattered data thereafter and literature review shows that about cases have been reported so far [ 5 — 15 ]. This report is an attempt to help the dental community in developing familiarity with the clinical presentation of desmoplastic ameloblastoma and at the same time emphasizing an index of suspicion in recognizing and treating the peculiar aspect of this unusual lesion.
The swelling had started 1 year previously and since then, there had been a gradual increase to its present size. She denied experiencing any bleeding, pain or sensory changes. She also denied any history of trauma and the past medical, dental and family history was insignificant. On physical examination, facial asymmetry due to swelling on the left side of the face was noticed. The swelling was oval in shape crossing the midline thereby obliterating the labiomental sulcus.
The swelling had smooth surface with normal overlying skin but stretched. It was non-tender on palpation. Buccal expansion of the mandibular left and right symphyseal and para-symphyseal region was evident.
The overlying mucosa appeared normal. There was labial displacement of 32 Fig. On palpation, the swelling was found to be firm, bony hard in consistency, non-tender, non-fluctuant, irreducible, non-compressible and non-pulsatile. The teeth in the vicinity were non-tender to percussion; there was slight mobility of 32 and On electric pulp vitality testing, all teeth in the affected area were vital except 32 and No lymphadenopathy or fistulae were present.
The lesion resulted in the displacement of the roots of 32 and 33 without any signs of root resorption. There was loss of periodontal ligament space on the involved teeth except lower right canine and lower left first premolar.
There was loss of lamina dura around the involved teeth. Areas of calcifications were present within the lesion giving it a soap bubble appearance. The lesion almost involved the lower border of the mandible. Panoramic radiograph showing mixed radiolucent radio-opacity with ill-defined borders extending from teeth 35 to A provisional diagnosis of a fibro-osseous lesion of the anterior mandible was made based on clinical and radiographic appearance.
The lesion was non-productive on aspiration. The final diagnosis was established through incisional biopsy performed under local anesthesia.
The histologic features were corroborating with those of desmoplastic ameloblastoma. A segmental resection of mandible from 44 to 35 was done under general anesthesia with proposed incision as shown in Figs. The surgical specimen consisted of a segment of mandible with the lesion and the associated teeth.
The frozen sections were found to be free of tumors. The post-operative period was uneventful. The incidence of desmoplastic ameloblastoma is low.
Although DAs are similar to conventional solid ameloblastomas regarding the age and gender distribution, tumors present a strong proclivity for the anterior region with equal incidences on either of the jaw [ 8 ]. DA occurs more commonly in the 4th or 5th decades of life, and has no preponderance towards either sex [ 18 ]. The mean age of occurrence is The majority of the cases has been reported particularly in Chinese residing in Malaysia and Hong Kong, Malaysians, Japanese and Afro-Caribbeans [ 20 ].
Reports from various geographical regions hint at relatively higher frequency of desmoplastic ameloblastoma in Asians [ 5 ]. However, more systematic studies on desmoplastic ameloblastoma is necessary to justify such suggestions. Coincidently, the present case of desmoplastic ameloblastoma is also seen in a chinese woman from northeast of china. According to Philipsen et al. The insidiousness of maxillary lesions to mandibular tumors are attributed to proximity to vital structures as well as the very thin cortical bone of the maxilla being a weak barrier favours the dissemination of tumors.
Therefore, maxillary ameloblastomas have potential to spread earlier and more rapidly than mandibular neoplasms. The extensive presentation of the desmoplastic ameloblastoma may be due to 1 relatively higher incidence in the maxilla leading to an early encroachment of adjacent vital structures 2 the ill-defined diffuse radiographic appearance.
Patient usually presents with a chief complain of painless swelling of the jaw bone. The tumor varies in size between 1. The patient described in this report also presented with painless swelling with no root resorption, but displacement of the adjacent teeth 32 and So far as the origin of DA is concerned, Kishino et al.
Moreover, some others are of the opinion that desmoplastic ameloblastoma may have its origin from epithelial rests of Malassez in the periodontal membrane [ 22 ]. It was hypothesized that this may be due to the infiltrative nature of DA to involve the trabeculae. Three radiological presentations of DA are mentioned in the literature as follows: type I osteofibrosis type which has radiolucent as well as radiopaque appearance; type II radiolucent type which has a completely radiolucent appearance; and type III compound type which has radiolucent as well as radiopaque appearance combined with a large radiolucent change [ 3 ].
Radiographic features of our case showed mixed radiodensities which were consistent with that of osteofibrosis type type 1 which is the most common pattern; the compound type is the least common. The lesion is characterized by osseous metaplasia within the dense fibrous septa and this may be the cause for mixed radiographic appearance, it may not be due to mineralized product by the tumor. According to study by Savithri et al.
The present case, too, lacked typical radiographic findings of ameloblastoma and we experienced a little difficulty in diagnosing it correctly. We suspected fibro-osseous lesion or odontogenic myxoma based on the radiographic findings.
The final diagnosis of desmoplastic ameloblastoma is based on histopathological evaluation of biopsy specimens. The usual microscopic features are: 1 extensive stromal desmoplasia with abundance of collagen and moderate amount of cellular connective tissue, which is the most consistent and distinguishing feature Fig.
Formation of metaplastic osteoid trabecular osteoplasia may be present. The pallisading pattern of follicles as observed in conventional ameloblastoma is absent. Myxoid changes of the juxtaepithelial stroma are often found. A fibrous capsule is not present corresponding to the radiographically poorly defined tumor margin. Histologically, the possibility of misdiagnosis of DA as another odontogenic tumor is high if biopsy specimen is not sufficient enough to warrant the presence of characteristic palisading layer of ameloblastoma in all the epithelial clusters.
DA may resemble odontogenic fibroma if presence of only narrow strands of epithelial cells are evident within desmoplastic stroma. The epithelium-poor type of central odontogenic fibroma COF is a non-infiltrating lesion of connective tissue that mimics a dental follicle. It contains little cellular component with scattered delicate collagen fibres. The presence of significant quantity of ground substance gives a fibromyxoid appearance to the background in contrast to myxoid changes in the juxtaepithelial stroma in desmoplastic ameloblastoma.
Scattered remnants of inactive-looking odontogenic epithelium appear as small irregular islands and cords. Occasionally, variably formed calcifications occur. The epithelium rich type of odontogenic fibroma is composed of cellular, fibroblastic connective tissue that are intermingled with less cellular but vascularized areas.
Foci of calcified collageneous matrix mimicking dysplastic cementum, dentin or osteoid are often present. Islands or strands of inactive-looking odontogenic epithelium forms an essential component which may be sparse but are often obvious in contrast to stromal components compressing odontogenic epithelium making epithelial tumor islands very irregular or bizarre with pointed stellate appearance in case of desmoplastic ameloblastoma.
The correct diagnosis of these two tumors signifies the clinical behavior and approaches for their management. Ameloblastoma being potentially aggressive tumor requires en bloc resection whereas odontogenic fibroma being much less aggressive requires enucleation. Squamous odontogenic tumor also comes under differential diagnosis of DA.
DA resembles squamous odontogenic tumor if metaplasia of squamous epithelium is evident in some areas but palisading layer of tall columnar cells are not visualized [ 23 ].
The islands and strands of DA are often thin and compressed rather than rounded and broad based as seen in squamous odontogenic tumor SOT. Despite of the aggressive clinical course of some of the SOT, the presently preferred treatment is curettage following which few recurrences may occur.
Another differential diagnosis is sclerosing odontogenic carcinoma which is characterized by dense sclerotic stroma containing numerous infiltrating thin cords and small nests of cuboidal or polygonal epithelial cells. The epithelial cells primarily have eosinophilic cytoplasm although some areas of cytoplasmic clearing and a signet-ring may appear. In contrast, DA usually contains large epithelial nests with central spindle cells.
Their nuclei show hyperchromatism and slight atypia in contrast to occasional hyperchromastism and no cellular atypia in desmoplastic ameloblastoma. The malignant potential is characterized by encroachement of skeletal muscle and perineural spread. The identification of typical ameloblastic areas forms the basis for definitive diagnosis of DA which requires examination of adequate tissue or repeated biopsy.
Desmoplastic Ameloblastoma - A Review
Desmoplastic Ameloblastoma is a rare variant of ameloblastoma. We are presenting a rare case of desmoplastic ameloblastoma in the ramus region of mandible with regards to its clinical and radiographical viewpoints. Only one other case of desmoplastic ameloblastoma has been reported in the ramus region of mandible of the 90 cases that we have reviewed. Review of literature has revealed the tumour to most commonly occur in the 3rd to 5th decade of life with a high preponderance of Japanese males. The anterior region of either jaw was most commonly found to be affected. However our case differed from the reviewed cases as it was found to be a unilocular lesion with well defined borders. Histopathological findings of our case were consistent with the hisotpathological appearance of the reviewed cases and showed extensive stromal desmoplasia and small tumour nests of odontogenic epithelium scattered in stroma.
Desmoplastic Ameloblastoma: A Case Report
Among the ameloblastomas, the desmoplastic variation is rare. The desmoplastic ameloblastoma DA is characterized by specific clinical, imaging, and histological features. The here presented retrospective analysis investigated the clinicoradiographic features of an overall of DA-cases, having been reported in literature from to Sixty-two lesions occurred in the mandible and fifty-one lesions in the maxilla. Clinically, a painless swelling with buccal extension was the most common presentation being found in 48 cases. Radiologically, the lesion often presented multilocular