|Ahead of print
Desmoplastic ameloblastoma of anterior maxilla - A case report
Madhur Manak1, Archana B Raina1, Jaishree Sharma2, Sita M Baddireddy2
1 Department of Periodontology, Dental Optima, MD Safe Hands C/O Vinod Raina
2 Department of Oral and Maxillofacial Pathology, Bhatnagar Dental Care
|Date of Submission||24-Jul-2021|
|Date of Decision||10-Nov-2021|
|Date of Acceptance||09-Dec-2021|
|Date of Web Publication||28-Oct-2022|
Department of Oral and Maxillofacial Pathology, Bhatnagar Dental Care
Source of Support: None, Conflict of Interest: None
The recently recognized desmoplastic ameloblastoma is considered a rare variant of central ameloblastoma. It has been included in the World Health Organization's histopathological typing of odontogenic tumors, similar to benign, locally invasive tumors with low recurrence rate and peculiar histological features, characterized by epithelial changes due to the pressure of stroma on epithelial tissue. The aim of this paper is to report a unique case of desmoplastic ameloblastoma in the mandible of a 21-year-old male with a painless swelling in the anterior region of the maxilla. To our knowledge, only a few cases of adult patients affected by desmoplastic ameloblastoma have been published.
Keywords: Ameloblastoma, desmoplastic ameloblastoma, odontogenic tumors
| » Introduction|| |
Ameloblastoma of the jaw is a neoplasm that accounts for approximately 1% of all cysts and tumors of the jaws. Desmoplastic ameloblastoma (DA) was included in the World Health Organization classification of head and neck tumors (WHO-2005) as a variant of ameloblastoma with specific clinical, image, and histological features. The follicular and plexiform varieties of ameloblastoma are the 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. DA was first described in 1984 by Eversole et al. as a tumor presenting extensive stromal desmoplasia with small nests, cords, and strands of tumoral odontogenic epithelium. Additionally, “hybrid” lesions showing some microscopic features of the desmoplastic variant together with typical areas of follicular or plexiform ameloblastoma have been described. Radiologically, the DA frequently presented as diffuse, mixed radiolucent–radiopaque lesion, apt to be misdiagnosed as fibro-osseous lesion. The purpose of this paper is to report a unique case of desmoplastic ameloblastoma in the maxilla of a 21-year-old male with a painless swelling in the anterior region of the maxilla.
| » Case History|| |
A 21-year-old male patient reported with a chief complaint of a swelling in the left upper front tooth region, which is now increasing in size significantly from the last 6–7 months. History of present illness revealed that swelling in the left upper labial vestibule was present since his childhood and the size of the swelling has increased since the last 6–7 months. The swelling was bony hard, with no associated pain or discharge. The swelling is present in association with 21, 22, 23, and 24 (FDI tooth numbering system). The patient reported no history of trauma/surgery. All the vital signs were within the normal range. On inspection, a swelling of approximately 5 cm × 5 cm was present with respect to 21, 22, 23, and 24 with normal overlying mucosa [Figure 1]. The swelling was present only on the labial side and not on the palatal side of the maxilla. On palpation, the swelling was bony hard in consistency with no associated pain or tenderness. Provisional diagnosis of adenoid odontogenic tumor was given with differential diagnosis of calcifying odontogenic cyst. Panoramic radiograph of the region concerned showed a diffuse ill-defined mixed radiolucent/radiopaque lesion extending from the mesial surface of the left lateral incisor to the mesial surface of the left first premolar, with an approximate size of 2 cm × 3 cm. The lesion caused a divergence of the root of 22 and 23 without any signs of root resorption. Small flecks of radiopacities were seen within the lesion. There was loss of lamina dura around the involved teeth. The floor of the maxillary sinus appeared radiographically intact [Figure 2]. The histopathological examination using H and E stain revealed irregular epithelial islands in a densely fibrous connective tissue stroma. The islands consist of peripheral cuboidal cells with central spindle cells arranged in a whorled pattern. Extensive desmoplasia was seen throughout the stroma. Moderately cellular connective tissue with thick collagen fiber bundles compressing the epithelial islands was also evident [Figure 3] and [Figure 4]. Odontogenic epithelial islands were positive for CD-138; positive immunohistochemical stain for type IV collagen suggests an inductive effect of the epithelium over the stroma, while the cytokeratins 18 and 19 were not expressed, which supports the benign biological behavior of this lesion [Figure 5] and [Figure 6].
|Figure 1: Clinical presentation showing swelling in the anterior region of the maxilla|
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|Figure 2: Panoramic radiograph showing mixed radio densities and tooth displacement of 22 and 23|
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|Figure 3: H and E stained photomicrograph showing small irregular islands and cords of odontogenic epithelium in a dense collagenous stroma (4×)|
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|Figure 4: The H and E stained photomicrograph showing compressed epithelium surrounded by desmoplastic stroma (10×)|
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|Figure 6: Positive expression of type IV collagen in the basal lamina of peripheral desmoplastic ameloblastoma|
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| » Discussion|| |
Desmoplastic ameloblastoma (DA) is a rare variant that accounts for approximately 4%–13% of ameloblastoma, displaying significant differences in the anatomical site, imaging, and histologic appearance. It has been included in the WHO classification of head and neck tumors (WHO-2005) as a variant of ameloblastoma. The tumor resembles a benign fibro-osseous lesion for being frequently occurring in the anterior region of jaws as a mixed radiopaque radiolucent lesion. Waldron introduced the term “hybrid lesions” and El-Mofty reported a condition in which desmoplastic ameloblastoma was present in close proximity to follicular or plexiform ameloblastoma. DA is a tumor with specific clinical, image, and histological features. In addition, DA is a rare form of tumor and has been described in 117 cases in English literature. DA exhibits a more aggressive behavior than other types of ameloblastoma. This aggressiveness may be due to 1) the potential to grow, 2) common location in the maxilla leading to an early invasion of adjacent structures, 3) diffuse radiographic appearance, or 4) histologic finding of bone invasion. Concerning the biological behavior of DA, it is mentioned in the WHO classification of odontogenic tumors that DA, like unicystic ameloblastoma and peripheral ameloblastomas, possibly have a lower recurrence rate than other ameloblastomas. The majority of the cases have been reported particularly in Chinese residing in Malaysia and Hong Kong, Malaysians, Japanese, and Afro-Caribbean. However, more systematic studies on desmoplastic ameloblastoma are necessary to justify such suggestions. So far as the origin of DA is concerned, Kishino et al. assumed that the desmoplastic ameloblastomas might have originated from the periodontal membrane as oxytalan fibers identified in the stromal tissue were stained by potassium monopersulfate-aldehyde fuchsin. Radiologically, there is not any agreement among DA reviews as to whether it deals with a radiolucent or mixed radiolucent–radiopaque lesion. The radiological presentations of DA are mentioned in the literature as follows: osteofibrosis type 1, which has radiolucent as well as radiopaque appearance; radiolucent type II, which has a completely radiolucent appearance; and compound type III, which has radiolucent as well as radiopaque appearance combined with a large radiolucent change. Our case showed mixed radio densities, which were consistent with that of osteofibrosis type 1, which is the most common pattern; compound type 3 is the least common. Histopathology is the gold standard for diagnosing such lesions. However, the possibility of misdiagnosis of DA as another odontogenic tumor is high if the biopsy specimen is not sufficient to warrant the presence of a characteristic palisading layer of ameloblastoma in all the epithelial clusters.
The DA is considered a rare lesion, but evidence suggests that it can be considered a distinct lesion. Not all ameloblastomas behave this aggressively; therefore, it is important to distinguish between clinical types of ameloblastoma to deliver qualitative treatment to patients.
It is an attempt to help the dental community in developing familiarity with the clinical as well as histopathological presentation and at the same time supporting to develop a high index of notion in diagnosing such cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]