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 Table of Contents  
CASE REPORT
Year : 2019  |  Volume : 14  |  Issue : 1  |  Page : 42-44

Plexiform unicystic ameloblastoma with adenoid differentiation: An unusual finding


1 Department of Oral Pathology, People's College of Dental Science and Research Centre, Peoples Campus, Bhopal, Madhya Pradesh, India
2 Department of Dentistry, Indira Gandhi Government Medical College and Hospital, Nagpur, Maharashtra, India
3 Department of Oral Medicine and Radiology, Government Dental College, Nagpur, Maharashtra, India

Date of Web Publication21-May-2019

Correspondence Address:
Dr. Amol Ramchandra Gadbail
Department of Dentistry, Indira Gandhi Government Medical College and Hospital, Nagpur, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jdmimsu.jdmimsu_53_18

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  Abstract 


Unicystic ameloblastoma (UA) shows clinical and radiologic characteristics of an odontogenic cyst, but histologically shows a typical ameloblastomatous epithelial lining part of the cyst cavity, with or without luminal and/or mural tumor proliferation. Very few cases were reported with variation in histological pattern but rarely with adenoid differentiation. Keeping this in mind, we here report a case report of plexiform UA with adenoid differentiation in maxilla.

Keywords: Adenoid differentiation, maxilla, plexiform, unicystic ameloblastoma


How to cite this article:
Yuwanati M, Dande R, Gadbail AR, Gondivkar S. Plexiform unicystic ameloblastoma with adenoid differentiation: An unusual finding. J Datta Meghe Inst Med Sci Univ 2019;14:42-4

How to cite this URL:
Yuwanati M, Dande R, Gadbail AR, Gondivkar S. Plexiform unicystic ameloblastoma with adenoid differentiation: An unusual finding. J Datta Meghe Inst Med Sci Univ [serial online] 2019 [cited 2019 Jun 16];14:42-4. Available from: http://www.journaldmims.com/text.asp?2019/14/1/42/258657




  Introduction Top


Unicystic ameloblastoma (UA), a variant of ameloblastoma, shows clinical and radiologic characteristics of an odontogenic cyst, but in histologic examination shows ameloblastomatous epithelial lining part of the cyst cavity, with or without luminal and/or mural tumor proliferation.[1] Gardner had mentioned that the pattern was indeed a form of ameloblastoma, based on his opinion on the high incidence of plexiform epithelial proliferation in association with histologically characteristic ameloblastoma: in some cases, the two histological patterns merge.[2] This variant is believed to be less aggressive, tends to affect patients at a younger age (second to third decades), and usually in the mandibular molar area. Maxillary lesions are very uncommon. The lesion is single cystic space, although many have cystic loculations. It may appear at the apex of a tooth or around the crown of an impacted tooth. It is usually small, although it can reach several centimeters in size. The UA show a typical ameloblastomatous epithelial lining with or without luminal and/or mural tumor growth.[1] The term plexiform refers to growth pattern of anastomosing islands of odontogenic epithelium in contrast to follicular pattern.[3] The UA may show plexiform pattern with little variation.[4] Very few cases were reported with variation in histological pattern but rarely with adenoid differentiation.


  Case Report Top


A 55-year-old male patient visited with the complaint of bad odor and intermittent watery discharge from the right posterior region of the maxilla for 1 year. There was no associated pain or swelling [Figure 1]a. The #3 was vital and noncarious. The patient had crown and bridge on the left side of the maxillary arch and broken silver filling on #4 and #5. The patient had extracted #2 due to caries. He did not have any contributory past history. The X-ray showed well-defined, oval-shaped radiolucency, with thin, continuous, smooth corticated borders, in the right posterior region of the maxilla, above and distal to #2 extending posteriorly. Floor of the right maxillary sinus was not traceable [Figure 1]b. The Posteroanterior water's radiograph showed haziness in the right maxillary sinus, and the lateral wall of the right maxillary sinus was not traceable [Figure 1]c. Computed tomography scan was suggestive of soft-tissue lesion extending to the right side of the maxillary sinus [Figure 1]d. The lesion was completely excised under local anesthesia. The specimen was oval in shape measuring up to 4.3 cm × 3.2 cm. It was smooth, shiny, and well capsulated. The cut surface of the specimen revealed multiple small cystic areas with outer fibrous capsule [Figure 2]a.
Figure 1: (a) Intraoral photograph showing tooth socket in the second molar region. (b) Well-defined, oval-shaped radiolucency with thin continuous smooth corticated borders seen maxillary posterior region. Floor of the right maxillary sinus is not traceable. (c) PA water's showing haziness in the right maxillary sinus, as well as the lateral wall of the right maxillary sinus is not traceable. (d) Coronal computed tomography scans showing Soft-tissue lesion in the right maxillary Sinus

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Figure 2: (a) The cut surface of the specimen showing small cystic areas with outer fibrous capsule. (b) A dense fibrous capsule lined with ameloblastic epithelium, with proliferation of star-shaped cell chains inside the tumor, causing the plexiform pattern. (c) The proliferating strands are composed of cuboidal-to-tall columnar cells with acanthomatous change in the stellate reticulum-like cells. (d) Plexiform pattern shows area of adenoid differentiation

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The cut surface of the specimen showed cystic space surrounded with a dense fibrous capsule and lined with ameloblastic epithelium, with proliferation of star-shaped cell chains inside the tumor, causing the plexiform pattern [Figure 2]b. There was intraluminal proliferation, which showed a predominance of proliferating strand-like growth pattern with interconnection of the epithelial strands and cords. The proliferating strands were composed of cuboidal-to-tall columnar cells with acanthomatous change in the stellate reticulum-like cells [Figure 2]c. Some areas of plexiform pattern showed area of adenoid differentiation [Figure 2]d. This area of adenoid differentiation showed tall columnar cells with varying nuclear polarization at the stromal interface. The capsule of the lesion contained ameloblastic follicles in the form of strands and cords. Histopathological diagnosis of plexiform UA with adenoid differentiation (Type II/III) was made based on findings.


  Discussion Top


Large series published on UA often make no mention of feature other than those classically described and most infrequent findings as case studies. On account of the reported case in the literature, UA is more common in younger age and mandible (body–ramus area) is the most common site affected. This has led to a generally accepted view that UA is homogeneous in its clinical and pathologic presentation. In a report by Gardner and Corio, 46 UAs, plexiform type, were found mostly in the mandible.[2] Common radiographic findings of the unicystic variant include a unilocular, well-circumscribed, and well-corticated lucent lesion often associated with the crown of an unerupted or impacted tooth which can resemble a dentigerous cyst or envelopmental variety of odontogenic keratocyst.[5] The presence of solid components, including internal bony septa, aids in the distinction between an ameloblastoma and a dentigerous cyst. Therefore, this lesion is often misdiagnosed as an odontogenic keratocyst or a dentigerous cyst. Konouchi et al.[6] performed contrast-enhanced (CE)-magnetic resonance imaging (MRI) to diagnose 13 cases of unilocular, round radiolucent lesions visualized by panoramic radiography and/or CT. In the cases of UA, low signal intensity (SI) was observed on T1-weighted images (WIs), a markedly high SI was observed on T2WIs, and relatively thick rim enhancement with/without small intraluminal nodules was observed on CE-T1WIs. CE-MRI was considered to be useful in the diagnosis of UA.

Histologically, UA prominently shows plexiform and follicular pattern along with a cystic lining of ameloblastic epithelium. Vickers and Gorlin suggested the histologic criteria for the diagnosis of UA. However, Gardner and Corio was in opinion that not all ameloblastomas fulfill the criteria which is true in our case, which does not rule out the exclusion of ameloblastoma.[2] In reported case, authors found histological plexiform pattern in UA with intraluminal growth. The plexiform growth shows an adenoid pattern. The UA exhibiting clear cell differentiation, adenomatoid odontogenic tumor (AOT) differentiation, and adenoid pattern were reported in a literature.[7],[8],[9] In the present case, cuboidal cell was arranged in glandular pattern but not resembling the pattern present in AOT. The lesion was well capsulated and can be easily separated from the tumor tissue which is not a usual finding in UA. This is an unusual histopathological finding in a UA. Considering the background of diversity in histological presentation, the biological behavior and prognosis of these tumors are uncertain as similar cases are not reported in literature. UA responses favorably to conservative treatment. The enucleation followed by curettage and liquid nitrogen cryospray or Carnoy's solution cauterization would be appropriate. In extensive lesions, marsupialization may be an alternative treatment.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their 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

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Li TJ, Wu YT, Yu SF, Yu GY. Unicystic ameloblastoma: A clinicopathologic study of 33 Chinese patients. Am J Surg Pathol 2000;24:1385-92.  Back to cited text no. 1
    
2.
Gardner DG, Corio RL. Plexiform unicystic ameloblastoma. A variant of ameloblastoma with a low-recurrence rate after enucleation. Cancer 1984;53:1730-5.  Back to cited text no. 2
    
3.
Marx RE, Stern D. Odontogenic tumors. In: Oral and Maxillofacial Pathology: A Rationale for Diagnosis and Treatment. 2nd ed. Illinois, USA: Quintessence Publishing; 2003. p. 671-64.  Back to cited text no. 3
    
4.
Ramesh RS, Manjunath S, Ustad TH, Pais S, Shivakumar K. Unicystic ameloblastoma of the mandible – An unusual case report and review of literature. Head Neck Oncol 2010;2:1.  Back to cited text no. 4
    
5.
White SC, Pharoaha MJ. Benign tumors of the jaws. In: White SC, Pharoha MJ, editors. Oral Radiology: Principles and Interpretation. 6th ed. St. Louis, MO: Mosby Elsevier; 2009. p. 366-4.  Back to cited text no. 5
    
6.
Konouchi H, Asaumi J, Yanagi Y, Hisatomi M, Kawai N, Matsuzaki H, et al. Usefulness of contrast enhanced-MRI in the diagnosis of unicystic ameloblastoma. Oral Oncol 2006;42:481-6.  Back to cited text no. 6
    
7.
Raubenheimer EJ, van Heerden WF, Noffke CE. Infrequent clinicopathological findings in 108 ameloblastomas. J Oral Pathol Med 1995;24:227-32.  Back to cited text no. 7
    
8.
Radhika M, Thambiah LJ, Paremala K, Sudhakara M. Clear cell unicystic ameloblastoma. J Oral Maxillofac Pathol 2011;15:109-12.  Back to cited text no. 8
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9.
Ghasemi-Moridani S, Yazdi I. Adenoid ameloblastoma with dentinoid: A case report. Arch Iran Med 2008;11:110-2.  Back to cited text no. 9
    


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