|Year : 2015 | Volume
| Issue : 3 | Page : 203-205
Diagnostic dilemma: Radicular cyst or keratocystic odontogenic tumor?
Shubhankar Dasgupta, Shalu Rai, Deepankar Misra, Sapna Panjwani, Nivedita Singh
Department of Oral Medicine and Radiology, Institute of Dental Studies and Technologies, Modinagar, Uttar Pradesh, India
|Date of Web Publication||4-Aug-2015|
Professor and Head, Department of Oral Medicine and Radiology, Institute of Dental Studies and Technologies, Kadrabad, Modinagar - 201 201, Uttar Pradesh
Keratocystic odontogenic tumor was previously considered as a common cyst of developmental origin but now it is considered as a tumor of the oral cavity with high recurrence rate and it has an ability to mimic other jaw cysts. Present study is a case report of a 19 year old male presenting with apainful swelling in right lower face region. On clinical and radiographic examination, a provisional diagnosis of Radicular cyst was given. Histopathological examination revealed Keratocystic Odontogenic Tumor. KOT may look similar to endodontic lesion. The lesion was successfully treated by complete enucleation. The aim of the study is to report and distinguish a case of keratocystic odontogenic tumor simulating Radicular cyst because of its aggressive behavior and high recurrence rate.
Keywords: Computerized tomography, keratocystic odontogenic tumors, orthopantomogram, radicular cyst
|How to cite this article:|
Dasgupta S, Rai S, Misra D, Panjwani S, Singh N. Diagnostic dilemma: Radicular cyst or keratocystic odontogenic tumor?. SRM J Res Dent Sci 2015;6:203-5
|How to cite this URL:|
Dasgupta S, Rai S, Misra D, Panjwani S, Singh N. Diagnostic dilemma: Radicular cyst or keratocystic odontogenic tumor?. SRM J Res Dent Sci [serial online] 2015 [cited 2020 Jul 13];6:203-5. Available from: http://www.srmjrds.in/text.asp?2015/6/3/203/162186
| Introduction|| |
Correct treatment begins with the correct diagnosis. Arriving at a correct diagnosis require knowledge skill and art. Because many diseases have similar symptoms, the clinician must be in a state in determining the correct diagnosis.  Clinical and radiographic presentation of keratocystic odontogenic tumor (KCOT), poses a major diagnostic dilemma as they can be located at various sites mimicking other pathologies. Large unilocular KCOTs can be indistinguishable from cystic ameloblastomas.  Distinguishing KCOTs from other jaw cysts is essential as it is considered as a benign neoplasm and show high epithelial proliferative index. Hence, histopathological confirmation and segregation of KCOT from other jaw cysts is mandatory as KCOTs have a high recurrence and aggressive behavior.  The purpose of this paper is to report a case of an infected radicular cyst situated between the roots of mandibular molar teeth, simulating infected KCOT thus posing a diagnostic dilemma and distinguish it from other periapically positioned cyst because of its aggressive behavior and high recurrence rate.
| Case Report|| |
A 19-year-old male patient reported to Department of Oral Diagnosis and Radiology; Institute of Dental Studies and Technologies, Modinagar, Uttar Pradesh with the chief complaint of pain in right lower back tooth region for last 2 years. Pain was sudden in onset, sharp, continuous lasted for 2-3 min aggravated on taking food and relieved after taking medication. Patient visited a dentist who started root canal treatment after which he developed swelling on right lower third of the face which subsided after taking medication without relief in pain. On extra oral examination, diffuse erythema seen on right lower third of face extending from right parasymphysis to angle of mandible mediolaterally and from midpoint of imaginary line adjoining the corner of lip and the ear lobe to the inferior border of mandible supero-inferiorly measuring approximately 3 cm × 4 cm in diameter. On intra oral examination, we found a faulty restoration with respect to 46 and grossly carious 47. Vestibular tenderness and cortical expansion were elicited with 46 and 47. These teeth (46, 47) were found to be nonvital on vitality test [Figure 1].
Patient was advised for intra oral periapical radiograph, which revealed a well-defined radiolucency at distal root of 46 measuring about 3 cm in greatest dimension. Internal structure revealed a radiolucency within radiolucency giving a "bay formation" appearance.
Orthopantomogram (OPG) revealed presence of well-defined radiolucency on right body of mandible measuring approx. 3 cm × 3 cm extending from mesial root of 46 to distal root of 47 anteroposteriorly and from middle 3 rd of root of 46.47 to superior border of inferior alveolar canal supero-inferiorly. Small radiolucency was seen with respect to distal root of 46 suggestive of bay formation. Sclerotic borders of the radiolucency could not be appreciated on the OPG [Figure 2].
Based on the clinical and radiographic examination, a provisional diagnosis of infected radicular cyst was given, and a differential diagnosis of infected KCOT and lateral periodontal cyst was considered.
The patient was referred to the department of oral surgery for surgical enucleation of the cyst and removal of 46 and 47 under local anesthesia [Figure 3]. Fine-needle aspiration cytology was performed, and a cheesy white aspirate was obtained. Decortication was done with curettage and soft tissue mass along with lining was obtained and sent for histopathological examination. The wound was chemically treated with the help of Carnoy's solution for 1 min and closed with 3 interrupted sutures for complete hemostasis.
Histopathology revealed characteristic features of KCOT. The lesion had uniform parakeratinized squamous cell epithelium 5-8 cell thick with underlying connective tissue stroma. The epithelium appeared to be corrugated with palisaded cuboidal cells and polarized hyperchromatic nuclei, confirming the diagnosis of KCOT [Figure 4].
| Discussion|| |
Keratocystic odontogenic tumor was formerly called odontogenic kerato cysts (OKCs) which is epithelial developmental cysts and was first described by Phillipsen in 1956.  According to latest World Health Organization classification, OKCs are termed as KCOT on the basis of the tumor like characteristics of the lining epithelium and to better convey its neoplastic nature. It is a benign developmental odontogenic tumor with many distinguishing clinical and histopathological features. Among them are, a potential for locally destructive behavior, a relatively high recurrence rate and its association with nevoid basal cell carcinoma syndrome or Gorlin syndrome.  KCOTs are common in males than in females with the ratio of 1.6:1. The lesion occurs over a wide age range with a peak in the second and third decade of life. KCOT may occur in any part of the upper and lower jaw with majority occurring in the mandible, most commonly in the angle of the mandible and ramus. ,
In the present case clinically and radiographically diagnosed periapical cyst was found as KCOT after histopathological examination. Unlike epithelial cells of a keratocystic odontogenic tumor the basal cells of an inflammatory apical cyst are not capable of self-proliferation without stimulation by external signals such as inflammatory mediators, pro-inflammatory cytokines, and growth factors released by innate and adaptive immune cells during apical periodontitis. ,, Furthermore, KCOT can be mistaken easily for inflammatory lesions because almost half of the patients presenting with KCOTs show inflammatory symptoms such as pain, swelling and drainage.  KCOTs may appear as small unilocular radiolucencies and may occur adjacent to a nonvital or endodontically treated tooth.  Hence, radiographic and clinical characteristics of KCOTs are not pathognomonic signs and may lead to a difficult diagnosis especially when this lesion is adjacent to teeth with a nonvital pulp or inadequate root fillings. When an orthograde retreatment is ineffective, a retrograde retreatment with a biopsy is recommended because KCOT in an unusual location may simulate a periapical lesion. 
The use of advanced diagnostic aid such as computerized tomography (CT) displayed a significant role in the assessment of KCOT. This technique is accurate in; measuring the extent of the lesion, exact localization of perforation through the cortex and assessment of soft tissue involvement. Furthermore, CT has overwhelming features over conventional radiographs, which include lack of image superimposition with a high degree of accuracy and the possibility of three dimensional interpretation. 
Surgical treatment is highly necessary and 62% recurrences include because of thin and friable nature of capsule due to which inadequate surgical removal of cyst; bony perforation and adherence to surrounding soft tissue structure; de novo formation of cyst, that is, remnants of dental lamina not associated with the original KCOT, may transform in to KCOT. KCOTs with parakeratinized layer have a much higher tendency for recurrence than orthokeratinized variant. It has been reclassified as KCOT due to cyst's aggressive behavior, high mitotic activity histologically, and evidence of associated genetic and chromosomal abnormalities like mutation of the PTCHgene (Protein patched homolog gene). 
| Conclusion|| |
This case has shown that the clinical impression and radiographic picture are not distinctive enough to be used as the sole criterion for rendering a diagnosis of any cyst occurring in the periapical position. KCOTs occurring in such a location are commonly mistaken for inflammatory lesions of endodontic origin. It is also advised that in such cases advanced computed volumetric tomography should be advised for further diagnostic imaging. Due to high recurrence rate and aggressive behavior of KCOTs all the tissues removed from its position, should be submitted for histopathological evaluation and a definitive diagnosis.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]