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Year : 2017  |  Volume : 13  |  Issue : 2  |  Page : 374-377

Clear cell odontogenic carcinoma: A rare case report with emphasis on differential diagnosis

1 Department of Oral Pathology and Microbiology, Bharati Vidyapeeth Deemed University Dental College and Hospital, Sangli, Maharashtra, India
2 Department of Oral and Maxillofacial Surgery, Bharati Vidyapeeth Deemed University Dental College and Hospital, Sangli, Maharashtra, India

Date of Web Publication23-Jun-2017

Correspondence Address:
Uma Vasant Datar
Department of Oral Pathology and Microbiology, Bharati Vidyapeeth Deemed University Dental College and Hospital, Sangli, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-1482.187381

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 > Abstract 

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic malignancy with a female predilection, typically presenting as swelling in anterior region of mandible. CCOC was classified as a malignant neoplasm of odontogenic origin by the WHO in 2005 as it exhibits an aggressive growth pattern, local recurrence, and tendency of distant metastasis. Histologically, CCOC is characterized by sheets and islands of vacuolated/clear cells. Since clear cells are present in few odontogenic tumors, salivary gland neoplasms, and metastatic tumors to the jaws; presence of clear cells in a lesion of head and neck area poses a diagnostic challenge. Knowledge about the clinical course, histopathologic pattern, and immunoprofile of CCOC aids in differentiating it from other clear cell tumors. Herein, we present a case of CCOC in anterior mandibular region of 60-year-old female patient with an emphasis on its differential diagnosis from other clear cell lesions of the jaws.

Keywords: Anterior mandible, clear cells, clear cell odontogenic carcinoma, immunohistochemistry

How to cite this article:
Datar UV, Kamat MS, Kanitkar SS, Byakodi SS. Clear cell odontogenic carcinoma: A rare case report with emphasis on differential diagnosis. J Can Res Ther 2017;13:374-7

How to cite this URL:
Datar UV, Kamat MS, Kanitkar SS, Byakodi SS. Clear cell odontogenic carcinoma: A rare case report with emphasis on differential diagnosis. J Can Res Ther [serial online] 2017 [cited 2022 Nov 26];13:374-7. Available from: https://www.cancerjournal.net/text.asp?2017/13/2/374/187381

 > Introduction Top

Clear cell odontogenic carcinoma (CCOC) is a low-grade odontogenic carcinoma showing cells with clear cytoplasm arranged in sheets and islands.[1] Most of the CCOC typically present as swelling in anterior region of the mandible in elderly female patients. Radiographically, it exhibits ill-defined unilocular or multilocular radiolucency with tendency to cause bone destruction and tooth resorption.[1],[2] Detailed literature search suggests that only 96 cases of CCOC have been reported till date.[3],[4],[5],[6],[7],[8],[9] The present case report discusses the clinical, histological, and immunohistochemical characteristics of CCOC and sheds light on its diagnostic differences from the other clear cell lesions.

 > Case Report Top

A 60-year-old female patient presented with a complaint of swelling in the anterior region of the mandible since 1 year. Intraoral examination revealed a well-defined, dome shaped, nontender swelling of 3 cm in diameter, extending from tooth 33 to tooth 43. Both the buccal and lingual cortical plate expansions were evident [Figure 1]a. Regional lymph nodes were not palpable. On orthopantomogram [Figure 1]b, a well-defined corticated unilocular radiolucent lesion extending from tooth 33 to tooth 43 was seen. Root divergence of the central and lateral incisors was observed. Findings of general physical examination, ultrasonography (USG) of abdomen and chest radiographs were noncontributory. Based on clinical and radiographic features, a provisional diagnosis of odontogenic cyst was considered, the lesion was enucleated and the specimen was sent for histopathological diagnosis.
Figure 1: (a) Intraoral photograph of well defined, dome shaped swelling in the mandibular anterior region, (b) orthopantomogram showing well corticated, unilocular radiolucency extending from tooth 33 to tooth 43

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Histopathological examination revealed a poorly circumscribed tumor of odontogenic epithelium. The tumor cells were arranged in the form of islands and chords demonstrating a biphasic cell pattern [Figure 2]a. One cell population was composed of clear cell having clear to faintly eosinophilic cytoplasm [Figure 2]b. The other cell population is composed of basaloid cells with minimal amount of cytoplasm. Focally, ameloblast-like cells were noted [Figure 2]c. The clear cells were Periodic acid–Schiff positive and diastase labile [Figure 3]. The cells were negative for mucicarmine stain. The tumor cells were immunoreactive for pancytokeratin, epithelial membrane antigen p63. The tumor cells were nonreactive for S100, vimentin, desmin, alpha smooth muscle actin (SMA), calponin, and calretinin. Ki 67 [mib1] proliferation index was 40% [Figure 4]. With the histopathological features and immunohistochemical profile, the diagnosis of CCOC was established, and surgical resection was planned.
Figure 2: (a) Photomicrograph showing tumor cells arranged in form of islands and chords in hyalinized connective tissue stroma (H and E, ×4), (b) tumor islands showing biphasic pattern with centrally placed clear cells and peripheral basaloid cells (H and E, ×10), (c) tumor islands showing peripheral ameloblast-like cells (H and E, ×40), (d) photomicrograph showing central clear cells with centric small basophilic nucleus, distinct cell membrane and clear cytoplasm (H and E, ×40)

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Figure 3: (a) Photomicrograph depicting clear cells with Periodic acid–Schiff positive granules (Periodic acid–Schiff, ×40), (b) photomicrograph showing diastase labile clear cells (Periodic acid–Schiff with diastase, ×40)

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Figure 4: (a) Photomicrograph of intense cytokeratin expression by tumor cells (×40), (b) photomicrograph of moderate expression of epithelial membrane antigen by tumor cells (×40), (c) Ki 67 positive tumor cells (×40), (d) strong expression of p63 by tumor cells (×40)

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 > Discussion Top

CCOC is a rare odontogenic tumor. The histogenesis of CCOC is unclear literature suggests that clear cells in jaw lesions originate from dental lamina or cell rests of Malassez.[2] It is suggested that the presence of clear cells is an attempt to recapitulate the presecretory phase of ameloblast with the accumulation of glycogen.[6] Literature review reveals that CCOC commonly occurs in the sixth decade of life (range 17–89 years).[8] CCOC characteristically has female preponderance with male:female ratio 1:1.8 and affects mandible more frequently than maxilla.[5] Clinically, it presents as asymptomatic, slow growing swelling of long duration with a mean size of 4 cm in diameter; however, cases with pain, tooth mobility, paresthesia, and nonhealing ulcerations have been reported.[3] Radiographically, CCOC manifests as either unilocular or multilocular radiolucency which may be well or poorly demarcated.[5] In the present case, a well-defined, well corticated, unilocular radiolucency with divergence of associated teeth was observed.

Histopathologically, CCOC demonstrates three distinct patterns namely biphasic, monophasic, and ameloblastomatous. Biphasic type is the most common histological pattern that shows two distinctive cell population namely clear cells and basaloid cells. The “clear cells” show abundant clear to faintly eosinophilic cytoplasm, distinct cell membrane, central/eccentric uniform dark staining nuclei, and lack significant pleomorphism and mitotic activity.[1],[3],[8] The other cell type is dark staining basaloid cells with scant eosinophilic cytoplasm. Monophasic pattern consists entirely of clear cells. Ameloblastomatous pattern is least common with the presence of clear cells centrally and peripherally palisaded ameloblast-like cells.[3],[4],[5],[6],[7] Rarely, a combination of different histologic patterns can be encountered.[7] In the present case, predominantly biphasic pattern was noted, but focally ameloblastomatous pattern was evident [Figure 2]c and [Figure 2]d.

Clear cells are hallmark but not the pathognomonic feature of CCOC. They are noted in odontogenic, salivary, melanotic, renal, thyroid, and prostate tumors. Thus, the differential diagnosis of CCOC evokes a broad range of tumors with diverse histogenesis and biological behavior. The differentiation of these tumors is confounding because of the considerable overlap in their histologic features, thus posing a diagnostic challenge.[10],[11] The differential diagnoses for CCOC include clear cell variant of calcifying epithelial odontogenic tumor (CCCEOT), ameloblastic carcinoma, intraosseous variant of clear cell mucoepidermoid carcinoma (CCMEC), hyalinizing clear cell carcinoma (CCC), intraosseous variant of melanoma, metastatic tumors from kidney, thyroid, and prostate [Table 1].[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]
Table 1: Differential diagnoses of clear cell odontogenic carcinoma

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Absence of amyloid and Liesegang's ring calcification in the present case negated the possibility of CCCEOT. Lack of mucin and negative staining for S100, alpha SMA, vimentin, and calponin ruled out CCMEC.[5],[10],[11] Intraosseous location with central bone destruction, presence of palisaded peripheral cells, differentiated the present case from CCC.[6] Absence of sinusoidal vascularity, intramural hemorrhage, noncontributory findings of USG abdomen and chest radiographs ruled out the possibility of metastatic renal cell carcinoma.[13]

Till date, only one report has evaluated the proliferative index of CCOC to be 35.2 cells per high power field (HPF), in the present case the proliferative index was 40 cells per HPF.[3] A recent literature review [3] suggests that CCOC has potential for multiple recurrences (41%), metastasis (31%), thus demanding an aggressive treatment approach and long-term surveillance. Surgical resection with wide margins is the treatment of choice for CCOC, with adjuvant radiotherapy for cases showing perivascular and perineural invasion. The cases treated initially with conservative surgery showed higher recurrence rate as compared to those treated with surgical resection (86.7% vs. 29%).[9] Hence, CCOC is now considered as a high grade odontogenic malignancy.

 > Conclusion Top

Differentiating CCOC from other clear cell tumors of head and neck is crucial. Clinical presentation and histopathological pattern primarily aided in the diagnosis of CCOC in our case. Special stains and immunoprofiling acted as an adjuvant to rule out the other clear cell tumors. CCOC warrants a close and long-term follow-up since it has a low survival rate and recurrence and metastasis were reported as late as 20 years after first intervention.

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Conflicts of interest

There are no conflicts of interest.

 > References Top

Bang G, Koppang H. Clear cell odontogenic carcinoma. In Barnes L, Eveson JW, Reichart P, Sidransky, editors. World Health Organization Classification of Tumours. Pathology and Genetics of Head and Neck Tumours. Lyon: IARC Press, 2005. p. 292.  Back to cited text no. 1
Walia C, Chatterjee RP, Kundu S, Roy S. Clinical enigma: A rare case of clear cell odontogenic carcinoma. Contemp Clin Dent 2015;6:559-63.  Back to cited text no. 2
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Loyola AM, Cardoso SV, de Faria PR, Servato JP, Barbosa de Paulo LF, Eisenberg AL, et al. Clear cell odontogenic carcinoma: Report of 7 new cases and systematic review of the current knowledge. Oral Surg Oral Med Oral Pathol Oral Radiol 2015;120:483-96.  Back to cited text no. 3
Ganvir SM, Gajbhiye NY. An unusual presentation of clear cell odontogenic carcinoma in mandibular anterior region. J Oral Maxillofac Pathol 2014;18:442-8.  Back to cited text no. 4
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Swain N, Dhariwal R, Ray JG. Clear cell odontogenic carcinoma of maxilla: A case report and mini review. J Oral Maxillofac Pathol 2013;17:89-94.  Back to cited text no. 5
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Bilodeau EA, Hoschar AP, Barnes EL, Hunt JL, Seethala RR. Clear cell carcinoma and clear cell odontogenic carcinoma: A comparative clinicopathologic and immunohistochemical study. Head Neck Pathol 2011;5:101-7.  Back to cited text no. 6
Avninder S, Rakheja D, Bhatnagar A. Clear cell odontogenic carcinoma: A diagnostic and therapeutic dilemma. World J Surg Oncol 2006;4:91.  Back to cited text no. 7
Slater LJ. Odontogenic malignancies. Oral Maxillofac Surg Clin North Am 2004;16:409-24.  Back to cited text no. 8
Kalsi AS, Williams SP, Shah KA, Fasanmade A. Clear cell odontogenic carcinoma: A rare neoplasm of the maxillary bone. J Oral Maxillofac Surg 2014;72:935-8.  Back to cited text no. 9
Premalatha BR, Rao RS, Patil S, Neethi H. Clear cell tumours of the head and neck. An overview. World J Dent 2012;3:344-9.  Back to cited text no. 10
Said-Al-Naief N, Klein MJ. Clear cell entities of the head and neck: A selective review of clear cell tumors of the salivary glands. Head Neck Pathol 2008;2:111-5.  Back to cited text no. 11
Chen CY, Wu CW, Wang WC, Lin LM, Chen YK. Clear-cell variant of calcifying epithelial odontogenic tumor (Pindborg tumor) in the mandible. Int J Oral Sci 2013;5:115-9.  Back to cited text no. 12
Will TA, Agarwal N, Petruzzelli GJ. Oral cavity metastasis of renal cell carcinoma: A case report. J Med Case Rep 2008;2:313.  Back to cited text no. 13


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

  [Table 1]

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