Home | About us | Editorial board | Ahead of print | Current issue | Archives | Search | Submit article | Instructions | Subscribe | Advertise | Contact us |  Login 
National Journal of Maxillofacial Surgery
Print this page Email this page Small font sizeDefault font sizeIncrease font size
Users Online: 186

Table of Contents
Year : 2011  |  Volume : 2  |  Issue : 1  |  Page : 89-92  

Unicystic ameloblastoma: A diagnostic dilemma

1 Department of Oral and Maxillofacial Surgery, Maulana Azad Institute of Dental Sciences, New Delhi, India
2 Department of Oral and Maxillofacial Surgery, C.S.M. Medical University (Erstwhile K.G. Medical College), Lucknow, India

Date of Web Publication10-Oct-2011

Correspondence Address:
Zainab Chaudhary
C/o Dr Ravi Nehra, Ch. Daryao Singh Bldg, Upper Bazaar (Near Indian Bank), Modinagar, U.P.
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0975-5950.85863

Rights and Permissions

Ameloblastoma is a slow-growing, persistent and locally aggressive neoplasm of epithelial origin accounting for 10% out of 30% of all odontogenic tumors. According to the World Health Organization, ameloblastomas are classified into the following types: conventional, unicystic, and peripheral. Unicystic ameloblastoma (UA) refers to those cystic lesions that show clinical, radiographic, or gross features of a mandibular cyst, but on histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor growth. We report a case of young female with a radiolucent lesion in the right posterior mandible. Surgical removal of the lesion was performed, with differential diagnosis of a radicular cyst. However, histopathologic examination revealed UA. The patient was kept under observation and showed signs of local bone regeneration. The purpose of presenting this report of a clinical case of UA previously misdiagnosed as radicular cyst is to emphasize the significance of histopathologic examination of all tissue specimens recovered in surgery even when clinical and radiological finding are innocuous.

Keywords: Conservative treatment, radicular cyst, unicystic ameloblastoma

How to cite this article:
Chaudhary Z, Sangwan V, Pal U S, Sharma P. Unicystic ameloblastoma: A diagnostic dilemma. Natl J Maxillofac Surg 2011;2:89-92

How to cite this URL:
Chaudhary Z, Sangwan V, Pal U S, Sharma P. Unicystic ameloblastoma: A diagnostic dilemma. Natl J Maxillofac Surg [serial online] 2011 [cited 2022 Dec 8];2:89-92. Available from: https://www.njms.in/text.asp?2011/2/1/89/85863

   Introduction Top

Mandibular swellings can be caused by many benign lesions of odontogenic or non-odontogenic origin. The most common tumor of odontogenic origin is ameloblastoma which develops from epithelial cellular elements and dental tissues in various phases of development. It is a slow-growing, persistent and locally aggressive neoplasm of epithelial origin, affecting the posterior area of lower jaw in 80% of cases. [1] There are three forms of ameloblastomas, namely, multicystic, peripheral and unicystic tumors. [2]

The unicystic ameloblastoma (UA) is a less encountered variant of the ameloblastoma. It appears more frequently in the second or third decade with no sexual or racial predilection. It is almost exclusively encountered asymptomatically in the posterior mandible. [3] The clinical and radiological simulation of an UA with mandibular cyst often leads to simple enucleation of lesion.

This report highlights the importance of histopathologic analysis of any pathology in jaws even if it seems innocuous in clinical as well as radiological examination.

   Case Report Top

A 23-year-old female reported in the outpatient department with the chief complaint of an asymptomatic bony hard swelling in respect to the right posterior mandible, which gradually increased in size in the past 3 years to attain the present size of concern. Dental and medical history was insignificant. On clinical examination, there was evidence of a large non-tender, non-compressible, hard swelling measuring 2 × 2 cm on the right body of mandible, about 1 cm anterior to the posterior border of ramus, but no lymphadenopathy was noted. Overlying skin was normal in color, texture and consistency and was not adherent to the underlying swelling.

Intraoral examination revealed a painless swelling in the right posterior mandibular vestibule from right mandibular second premolar to the distal aspect of second molar on the same side. The swelling was firm and covered by normal mucous membrane [Figure 1]. In place of the right mandibular first molar, only root stumps were present, but molar and premolar adjacent to it tested vital.
Figure 1: Intraoral view

Click here to view

Radiographically, it presented as a unilocular, radiolucent lesion, well circumscribed by a radiopaque border, about 3 × 2 cm, extending from the root of second molar posteriorly to the root of the first premolar anteriorly [Figure 2]. The lesion also caused a displacement of the right inferior alveolar canal toward the cortical inferior border of the mandible.
Figure 2: Panoramic radiograph demonstrating well defined unilocular radiolucent lesion in the right mandible

Click here to view

The lesion was perforated with a wide bore needle to rule out vascular lesion and aspirate the content. The aspirate was sent for pathological evaluation and the report stated it to be a cystic fluid with inflammatory exudates, confirming the clinical and radiographic diagnosis of radicular cyst in association with root stumps of 46.

So, enucleation of cyst with extraction of root stumps of first molar was planned. Under local anesthesia, an incision was made from distal of third molar to the medial of canine. Mucoperiosteal flap was raised and it was possible to see a thin expanded cortical plate which was removed with a scalpel. The cavity contained fibrous tissue wall full of liquid.

The lesion with all its fibrous tissue lining was enucleated carefully to ensure complete removal. The remaining bone tissue showed normal contour and consistency without any clinical signs of lesion. Root stump of first molar was extracted and mucoperiosteal flap sutured back after thorough curettage and lavage of bony cavity.

The histopathologic examination of the removed lining revealed UA contrary to the provisional diagnosis of radicular cyst [Figure 3]. Hence, root canal of 47 and 45 was done and radiologic observation of patient to monitor the relapse of lesion was chosen as the well-defined cystic envelope ensured the complete removal.
Figure 3: Photomicrograph showing cyst lined by ameloblastic epithelium with hyperchromatic polarized basal layer

Click here to view

Presently, the patient is under follow-up since 1 year without any signs of relapse and with bony restoration in the affected area [Figure 4].
Figure 4: Panoramic radiograph showing bone regeneration in the affected area during 12-month follow-up

Click here to view

   Discussion Top

UA, first described by Robinson and Martinez in 1977, refers to those cystic lesions that show clinical, radiologic or gross features of a mandibular cyst, but on histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with/without luminal and/or mural tumor growth. It accounts for 5-10% of all intraosseous ameloblastomas. [3],[4],[5] UA is believed to be less aggressive and responds more favourably to conservative surgery than the solid or multicystic ameloblastomas. [6]

Histologically, the minimum criteria for diagnosing a lesion as UA is the demonstration of a single cystic sac lined by odontogenic (ameloblastomatous) epithelium often seen only in focal areas.

In a clinicopathologic study of 57 cases of UA , Ackermann [7] classified this entity into three histologic groups:

  1. luminal UA (tumor confined to the luminal surface of the cyst);
  2. intraluminal/plexiform UA (nodular proliferation into lumen without infiltration of tumor cells into connective tissue wall); and
  3. mural UA (invasive islands of ameloblastomatous epithelium in the connective tissue wall not involving the entire epithelium).

Another subgrouping by Philipsen and Reichart [8] has also been described as follows:

Subgroup 1: luminal UA;

1.2: luminal and intraluminal;

1.2.3: luminal, intraluminal and intramural; and

1.3: luminal and intramural.

The UA diagnosed as subgroups 1 and 1.2 can be treated conservatively (careful evaluation), whereas subgroups 1.2.3 and 1.3 showing intramural growths require radical resection. [3]

In the present case, radiologic presentation suggested a radicular cyst with decayed first molar and vital second molar and first and second premolars, although they were included in the cyst. Moreover, the cytological examination of aspirate taken during initial clinical examination showed normal cystic fluid with few inflammatory cells. Thirdly, there was no root resorption of any tooth which may indicate the aggressive nature of the lesion.

Hence, finally taking into account the age of the patient, clinical and radiologic features, the simple enucleation procedure was chosen as the treatment of choice, for it involves least patient morbidity and effect on the quality of life is minimal. It has also been advocated that vigorous curettage of the bone should be avoided as it may implant foci of ameloblastoma more deeply in bone. [9]

In the present case, histopathologic examination of the enucleated sample showed ameloblastic changes confined to luminal surface of the cyst, i.e. as in group I and subgroup I.

The patient is being followed up at regular intervals to check for any recurrences. Recurrence is also related to the histologic subtypes, among which those invading the fibrous wall have a rate of 35.7%, but others have a rate of only 6.7%. [10] UAs are considered to be less aggressive form of ameloblastomas and can be successfully removed by simple enucleation or less aggressive surgery.

In the present case, the diagnosis was possible only because histopathologic examination was performed in the enucleated material. Hence, we conclude that the surgical protocol must include the postoperative histopathologic examination for all lesions to rule out any ameloblastomatous changes, so that the patient can be followed up properly to take care of any recurrences happening.

   References Top

1.Gerzenshtein J, Zhang F, Caplan J, Anand V, Lineaweaver W. Immediate mandibular reconstruction with microsurgical fibula flap transfer following wide resection for ameloblastoma. J Craniofac Surg 2006;17:178-82.   Back to cited text no. 1
2.Philipsen HP, Reichart PA. Classification of odontogenic tumors and allied lesions. Odontogenic tumors and allied lesions. London: Quintessence Pub Co Ltd; 2004. p. 21-3.   Back to cited text no. 2
3.Philipsen HP, Reichart PA. Unicystic ameloblastoma. Odontogenic tumors and allied lesions. London: Quintessence Pub. Co. Ltd; 2004. p. 77-86  Back to cited text no. 3
4.Leider AS, Eversole LR, Barkin ME. Cystic ameloblastoma: A clinicopathological analysis. Oral Surg Oral Med Oral Pathol 1985;60:624-30.  Back to cited text no. 4
5.Gardner DG, Corio RL. Plexiform unicystic ameloblastoma: Variant of ameloblastoma with a low recurrence rate after enucleation. Cancer 1984;53:1730-5.  Back to cited text no. 5
6.Robinson L, Martinez MG. Unicystic ameloblastoma: A prognostically distinct entity. Cancer 1977;40:2278-85.  Back to cited text no. 6
7.Ackermann GL, Altini M, Shear M. The unicystic ameloblastoma: A clinicopathological study of 57 cases. J Oral Pathol 1988;17:541-6.  Back to cited text no. 7
8.Chana JS, Chang YM, Wei FC, Shen YF, Chan CP, Lin HN, et al. Segmental mandibulectomy and immediate free fibula osteoseptocutaneous flap reconstruction with endosteal implants: An ideal treatment method for mandibular ameloblastoma. Plast Reconstr Surg 2004;113:80-7.  Back to cited text no. 8
9.Li TJ, Kitano M, Arimura K, Sugihara K. Recurrence of unicystic ameloblastoma: A case report and review of the literature. Arch Pathol Lab Med 1998;122:371-4.  Back to cited text no. 9
10.Li T, Wu Y, Yu S, Yu G. Clinicopathological features of unicystic ameloblastoma with special reference to its recurrence. Zhonghua Kou Qiang Yi Xue Za Zhi 2002;37:210-2.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

This article has been cited by
1 Unicystic Ameloblastoma Mimicking Lateral Periodontal Cyst
Maya Fedhila, Raouaa Belkacem Chebil, Sonia Karray, Badreddine Sriha, Lamia Oualha, Nabiha Douki, Junichi Asaumi
Case Reports in Dentistry. 2022; 2022: 1
[Pubmed] | [DOI]
2 Fluid aspirates of ameloblastoma: Types, prevalence, and prognostic relevance
MarkC Nwoga
International Journal of Medicine and Health Development. 2022; 27(4): 385
[Pubmed] | [DOI]
3 The Diagnostic Dilemma of an Odontogenic Jaw Lesion in a Pediatric Patient: A Case Report
Rutuja Ragit, Punit Fulzele, Nilima R Thosar, Monika Khubchandani
Cureus. 2022;
[Pubmed] | [DOI]
4 Unusual Variant of Unicystic Ameloblastoma with CEOT-Like Areas: A Rare Case Report with Review of Literature
Venkata Ramanand Oruganti,Shylaja Sanjeevareddygari,Manay Srinivas Munisekhar,Sharath Kumar Reddy Eppalapalli,Raghu Vamshi Vishwakarma,Kiran Kumar Ganji,Kiran R. Halkai,Rahul Halkai,Tommaso Lombardi
Case Reports in Dentistry. 2021; 2021: 1
[Pubmed] | [DOI]
5 Clinicopathological Profile of 80 Cases of Unicystic Ameloblastoma Aided by a Histopathological Comparison Using Modified Philipsen–Reichart Classification and Marx–Stern Classification
Rahul Anand,Anjali Narwal,Deepak Pandiar,Mala Kamboj,Anju Devi,Shikha Saxena,Krishna Sireesha Sundaragiri,Vijay Wadhwan,Vandana Reddy,Jiji George
Head and Neck Pathology. 2021;
[Pubmed] | [DOI]
6 Infected multilocular unicystic ameloblastoma involving ramus and coronoid process: A rare case report
Nikhil Saxena,SnehaH Choudhary,SamiD Aldhuwayhi,Amar Thakare
Contemporary Clinical Dentistry. 2020; 11(2): 179
[Pubmed] | [DOI]
7 Mural Unicystic Ameloblastoma mimicking Odontogenic Cyst
Karthika Panneerselvam,B Kavitha,Elavenil Panneerselvam,Anantanarayanan Parameswaran
Journal of Family Medicine and Primary Care. 2020; 9(5): 2524
[Pubmed] | [DOI]
8 Bilocular unicystic ameloblastoma of the mandible in a 9 yr old child – A diagnostic and management dilemma
Faisal Al Sineedi,Yasin Alavi Aruveetil,Abdul Majeed Kavarodi,Shawqi Osman Harbi
The Saudi Dental Journal. 2018;
[Pubmed] | [DOI]
9 Unicystic ameloblastoma: Analysis of 370 cases in a single center in Sri Lanka
Bogahawatte Samarakoon Mudiyanselag Siriwardena,Tennakoon Mudiyanselage Priyanka Ba Tennakoon,Keith D. Hunter,Wanninayake Mudiyanselage Tilakaratne
Journal of Oral Pathology & Medicine. 2018;
[Pubmed] | [DOI]
10 Unicystic Ameloblastoma with Mural Proliferation Managed by Conservative Treatment
Natália Galvão Garcia,Denise Tostes Oliveira,Moacyr Tadeu Vicente Rodrigues
Case Reports in Pathology. 2016; 2016: 1
[Pubmed] | [DOI]
11 Maxillary unicystic ameloblastoma: a case report
Zana Agani,Vjosa Hamiti-Krasniqi,Jehona Recica,Mergime Prekazi Loxha,Fisnik Kurshumliu,Aida Rexhepi
BMC Research Notes. 2016; 9(1)
[Pubmed] | [DOI]
12 Ameloblastoma during pregnancy: a case report
Helbert Eustáquio Cardoso da Silva,Erika do Socorro Ramos Costa,Antônio Carlos Quintão Medeiros,Paulo Sérgio dos Santos Pereira
Journal of Medical Case Reports. 2016; 10(1)
[Pubmed] | [DOI]
13 Role of deeper sections in diagnosis of unicystic ameloblastoma: A Case Report
Uma Vasant Datar,Mamata Kamant,Sampada Kanitkar
Journal of Scientific Dentistry. 2016; 6(2): 56
[Pubmed] | [DOI]
14 Unicystic Ameloblastoma Presenting as a Multilocular Radiolucency in the Anterior Mandible: A Case Report
Nigel R. Figueiredo,Manoj Meena,Ajit D. Dinkar,Sonam Malik,Manisha Khorate
Journal of Dental Research, Dental Clinics, Dental Prospects. 2015; 9(3): 199
[Pubmed] | [DOI]
15 Current Concepts and Occurrence of Epithelial Odontogenic Tumors: I. Ameloblastoma and Adenomatoid Odontogenic Tumor
Suk Keun Lee,Yeon Sook Kim
Korean Journal of Pathology. 2013; 47(3): 191
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
   Case Report
    Article Figures

 Article Access Statistics
    PDF Downloaded1042    
    Comments [Add]    
    Cited by others 15    

Recommend this journal