Int. J. Oral Maxillofac. Surg. 2014; 43: 1326–1329 http://dx.doi.org/10.1016/j.ijom.2014.06.008, available online at http://www.sciencedirect.com
Case Report Head and Neck Oncology
FDG-PET/CT in staging of clear cell odontogenic carcinoma
R. Krishnamoorthy, A. S. Ravi Kumar, M. Batstone Department of Oral and Maxillofacial Surgery & Department of Nuclear Medicine and Specialised PET Services, Royal Brisbane Hospital, Queensland, Australia
R. Krishnamoorthy, A. S. Ravi Kumar, M. Batstone: FDG-PET/CT in staging of clear cell odontogenic carcinoma. Int. J. Oral Maxillofac. Surg. 2014; 43: 1326–1329. Crown Copyright # 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
Abstract. Clear cell odontogenic carcinoma (CCOC) is a rare neoplasm; only 75 cases have been reported in the English language literature. They have a tendency for recurrence and a capacity to metastasize. There is very little known regarding the metabolic features of this tumour or the utility of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans in the staging and follow-up of these tumours. We present two cases of CCOC with their relevant FDG-PET/CT scan findings. The first patient had primary CCOC of the mandible that was FDG-avid, and the other had recurrence of CCOC of the anterior mandible and superomedial orbit that was not FDG-avid. FDG uptake in CCOC appears to be variable. Although FDG-PET/CT is useful in other head and neck cancers and has benefits compared to other imaging modalities, further studies are needed to investigate the sensitivity of FDG-PET/CT in CCOC.
Accepted for publication 17 June 2014 Available online 9 July 2014
Positron emission tomography (PET) using 18 F-fluoro-2-deoxy-D-glucose (FDG) is well established as a useful imaging tool for the staging of squamous cell carcinoma of the head and neck.1 PET-only scanners have also largely been replaced by hybrid PET/computed tomography (PET/CT) scanners. FDG is a marker of glucose metabolism and is the most widely used radiotracer in oncological PET/CT. PET scanning has been shown to add incremental diagnostic and prognostic information in a wide range of malignancies. There is a broad correlation between the degree of FDG avidity and tumour aggressiveness and clinical prognosis. Many (but not all) types of head and neck cancer also demonstrate increased glucose metabolism, and
and pulmonary metastases, and tumourrelated deaths, it was formally reclassified as malignant by the World Health Organization in 2005.5 CCOC has a loco-regional recurrence rate of 34% for resected tumours, and a distant metastatic spread rate of 14%.2 Sites of distant metastasis are most commonly the lungs, but there have been reports of metastasis to distant bone.2,6 Despite their tendency for recurrence and capacity to metastasize, a review of the literature revealed little information regarding the glucose metabolism of these lesions or the role of FDG-PET/CT in the staging and follow-up of these aggressive tumours. We present two cases of CCOC with their relevant FDG-PET/CT findings; the
0901-5027/01101326 + 04
FDG-PET/CT scanning has proven clinical value in squamous cell carcinomas and thyroid carcinomas in particular. However there are no cases in the literature exploring its use in clear cell odontogenic carcinoma (CCOC). CCOC is a rare neoplasm; only 75 cases have been reported in the English language literature.2 It commonly presents in the fifth to seventh decades of life and disproportionately affects women.3 The anterior regions of the jaws are more frequently affected, and it is more common in the mandible than the maxilla.3 CCOC was first described by Hansen et al. as a benign separate entity.4 However, as a result of evidence of a marked tendency for local recurrence, regional lymph node
Crown Copyright # 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
FDG-PET/CT in clear cell odontogenic carcinoma first patient had primary CCOC of the mandible with FDG-avid disease, and the other had recurrence of CCOC of the anterior mandible and superomedial orbit with disease that was not FDG-avid.
Case reports Case 1
A 59-year-old woman was referred by her dentist after an incidental finding of a painless lesion of the left body of the mandible. On presentation, she also complained of paraesthesia of the left lip and chin for 2 months and a 3-kg unintentional weight loss. Physical examination revealed a firm left mandible swelling with intact mucosa and left chin and lip numbness. Cervicofacial lymph nodes were not palpable. An orthopantomogram of the mandible showed a large lytic lesion in the left hemimandible with poor margination. CT and magnetic resonance imaging (MRI) showed a left mandibular lesion that involved extensive areas of the body and anterior mandible. An incisional biopsy and immunoperoxidase stain supported the diagnosis of CCOC. The patient was referred to a tertiary hospital for further investigation and treatment. The staging FDG-PET/CT scan showed a left mandibular mass exhibiting markedly increased, slightly irregular FDG uptake (Fig. 1a). There was mild FDG uptake crossing the midline into the anterior aspect of the right body of the mandible, which raised the possibility of infiltration
across the midline. There was mild to moderate FDG uptake in bilateral level IIA neck lymph nodes possibly indicating low volume nodal metastatic disease or inflammatory changes (Fig. 1b). No evidence of distant metastasis was found. The patient underwent a left hemimandibulectomy with bilateral neck dissection and left fibula free flap reconstruction. Postoperative histopathological evaluation confirmed the diagnosis of intraosseous CCOC of the mandible. The tumour was found to have extensive involvement of soft tissues with a 39-mm depth of invasion. Surgical margins were involved and numerous perineural invasions were identified. On microscopic examination, one left level 1 neck lymph node was found to have a 5-mm tumour deposit and all other dissected lymph nodes were negative. Immunohistochemistry results further supported the diagnosis of CCOC. Currently 2 months post-procedure, the patient has commenced a 4-week course of adjuvant radiotherapy given the positive surgical margins. Case 2
The patient was a 68-year-old woman with a history of a midline anterior maxillary CCOC arising in March 2009. She underwent a maxillectomy at that stage and the defect was restored with an obturator. She was found to have a close surgical margin and underwent a subsequent procedure with no residual tumour. She had been well for 4 years postoperatively.
1327
In 2013 she presented to her local doctor with a 6-week history of paraesthesia in the left infraorbital nerve and zygomaticotemporal nerve. On examination, she was found to have watering of the left eye with normal extraocular movements and visual acuity. She had an obvious swelling over the left maxilla, lateral nasal bones, and zygoma. There was also swelling intraorally over the left maxillary alveolus with no mucosal defects found. Cervicofacial lymph nodes were not palpable. A CT scan of the head and neck showed an obvious mass in the left anterior maxilla, with local extension and bony destruction that was suspicious for recurrence. There were two other areas noted in the left posterior maxilla and a superomedial orbit lesion invading through the skull base. CT of the chest and upper abdomen showed no evidence of metastatic disease. The FDG-PET/CT scan showed markedly increased FDG uptake of the left posterior maxillary lesion (Fig. 2a). However, there was only mild FDG uptake by the left anterior maxillary lesion and superomedial orbit, which was non-specific (Fig. 2b). A biopsy of the left posterior maxilla was performed, showing an inflamed granuloma only (site of markedly increased FDG uptake), and biopsy of the left anterior maxilla (site of only mild FDG uptake) showed a recurrence of COCC. The superomedial orbital lesion was not biopsied due to its location and risks, but given CT findings was assumed to represent recurrence. The patient is currently considering radiotherapy.
Fig. 1. Case 1 FDG-PET/CT showing (a) an FDG-avid primary of the left mandible, and (b) mild to moderate FDG uptake in the bilateral level IIA neck lymph nodes.
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Krishnamoorthy et al.
Fig. 2. Case 2 FDG-PET/CT showing (a) an FDG-avid left posterior maxillary lesion, biopsy proven granuloma, and (b) a negative left anterior maxillary lesion and superomedial orbit, biopsy proven recurrence of CCOC.
Discussion
PET scans are commonly performed with FDG, a glucose analogue tracer. FDG enters the cell though the glucose transport proteins, where it is phosphorylated to FDG-6-phosphate, which is not further metabolized and thus trapped in the cell. Cancer cells have a higher glycolytic rate, thus take up FDG more actively than normal cells. The radioactive label fluorine-18 in the intracellularly trapped FDG decays with a half-life of 110 min by positron emission. The positrons then undergo an annihilation reaction with surrounding electrons in tissue, which creates a pair of gamma rays travelling in approximately opposite directions. These ‘annihilation events’ are detected and reconstructed to produce a PET scan image. A near contemporaneous CT scan can also be acquired in a hybrid PET/CT scanner. The CT scan is used for a PET image reconstruction process called ‘attenuation correction’, and additionally has clinical diagnostic value. The clinical application of FDG-PET/ CT in head and neck cancer mainly includes assessment of primary tumours before treatment and the assessment of recurrence and response to treatment. The FDG avidity of CCOC is unknown. In our two cases, the first patient had a left mandibular mass exhibiting markedly increased, slightly irregular FDG uptake that was later biopsy confirmed as CCOC. However, in the second case the biopsy proven CCOC malignancy of the left posterior maxilla had only mild FDG uptake. The CT scan clearly demonstrated lesions that were also later biopsy confirmed as
recurrence. This raises concern that FDGPET also has variable sensitivity to detect the metastatic spread of CCOC. FDG-PET is both more sensitive and more specific than conventional imaging in the identification of nodal metastases in other head and neck cancers. However, it is important to recognize that FDG-PET scans provide a map of glucose metabolism in the body, and all foci of FDG uptake should not be assumed to have a malignant cause. While the degree of FDG uptake may be used as a guide to the likelihood of malignancy, low tumour volumes and certain types of poorly metabolic malignancy may also show low levels of FDG uptake. ‘False-positives’ can also occur from inflammatory or infectious phenomena because aggregates of macrophages and lymphocytes demonstrate increased glucose metabolism. This was evident in our second case, where the biopsy of the FDG-avid lesion showed an inflamed granuloma. ‘False-negatives’ can occur, as lymph node micrometastases may not be detected on FDG-PET/CT scans (or any other conventional anatomical imaging modalities). In our first case, level 1 lymph nodes were not FDG-avid, although histopathology showed a small 5-mm metastasis. Large areas of acellular necrosis or lymph node proximity to the tumour can also lead to reduced FDG uptake and ‘false-negatives’. Initial imaging with FDG-PET/CT is useful in investigating regional lymph node status, distant metastases, and synchronous primaries.1 An additional benefit of FDG-PET/CT in the initial staging is that it can image the entire body as a single study and with potentially a much lower
dose of radiation than whole-body diagnostic CT.7 A literature review revealed case series and reports of CCOC where chest radiography, abdominal ultrasound, CT, and bone scans were used to investigate for metastases; however FDG-PET/CT findings have not been described in detail. Furthermore, there have been no research studies reported in the English language literature to-date investigating the efficacy of PET/CT in the staging of CCOC. Our first case demonstrated marked FDG uptake for a biopsy proven CCOC and this could mean that it may reliably identify metastases in that patient. In contrast, in our second case the low level of FDG uptake in the recurrent CCOC suggests that FDG-PET would be an unreliable tool to identify metastasis in that patient. In conclusion, while there is potential utility of FDG-PET/CT scans in the evaluation of CCOC, sensitivity appears uncertain. Although FDG-PET has proven benefits compared to other imaging modalities in other head and neck cancers, further studies are needed to investigate the role of FDG-PET/CT in CCOC. In particular, molecular studies investigating glucose metabolism in CCOC tumour cells may help explain the apparently variable FDG-PET avidity of these neoplasms. The rarity of these tumours poses a challenge and multi-centre trials or international data registries may be required. Funding
There were no study sponsors involved in the study design, in the collection, analysis
FDG-PET/CT in clear cell odontogenic carcinoma and interpretation of data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.
3.
Competing interests
There were no financial or personal relationships with other people or organizations that could inappropriately have influenced (biased) this work.
4.
5.
References 1. Wong RJ. Current status of FDG-PET for head and neck cancer. J Surg Oncol 2008;97: 649–52. 2. Kalsi AS, Williams SP, Shah KA, Fasanmade A. Clear cell odontogenic carcinoma: a rare
6.
neoplasm of the maxillary bone. J Oral Maxillofac Surg 2014;72:935–8. Li TJ, Yu SF, Gao Y, Wang EB. Clear cell odontogenic carcinoma: a clinicopathologic and immunocytochemical study of 5 cases. Arch Pathol Lab Med 2001;125: 1556–71. Hansen LS, Eversole LR, Green TL, Powell NB. Clear cell odontogenic tumor—a new histologic variant with aggressive potential. Head Neck Surg 1985;8:115–23. Barnes L, Eveson JW, Reichart P, Sidransky D. Pathology and genetics of head and neck tumours. Lyon: IARC Press; 2005: 284. Kumar M, Fasanmade A, Barret AW, Mack G, Newman L, Hyde NC. Metastasising clear cell odontogenic carcinoma: a case report and review of the literature. Oral Oncol 2003;39: 190–4.
1329
7. Duet M, Hugonnet F, Faraggi M. Role of positron emission tomography (PET) in head and neck cancer. Eur Ann Otorhinolaryngol Head Neck Dis 2010;127:40–5.
Address: Ragu Krishnamoorthy Department of Oral and Maxillofacial Surgery Gold Coast University Hospital 1 Hospital Blvd Southport Queensland 4215 Australia E-mail: [email protected]
Case Report Head and Neck Oncology
FDG-PET/CT in staging of clear cell odontogenic carcinoma
R. Krishnamoorthy, A. S. Ravi Kumar, M. Batstone Department of Oral and Maxillofacial Surgery & Department of Nuclear Medicine and Specialised PET Services, Royal Brisbane Hospital, Queensland, Australia
R. Krishnamoorthy, A. S. Ravi Kumar, M. Batstone: FDG-PET/CT in staging of clear cell odontogenic carcinoma. Int. J. Oral Maxillofac. Surg. 2014; 43: 1326–1329. Crown Copyright # 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
Abstract. Clear cell odontogenic carcinoma (CCOC) is a rare neoplasm; only 75 cases have been reported in the English language literature. They have a tendency for recurrence and a capacity to metastasize. There is very little known regarding the metabolic features of this tumour or the utility of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans in the staging and follow-up of these tumours. We present two cases of CCOC with their relevant FDG-PET/CT scan findings. The first patient had primary CCOC of the mandible that was FDG-avid, and the other had recurrence of CCOC of the anterior mandible and superomedial orbit that was not FDG-avid. FDG uptake in CCOC appears to be variable. Although FDG-PET/CT is useful in other head and neck cancers and has benefits compared to other imaging modalities, further studies are needed to investigate the sensitivity of FDG-PET/CT in CCOC.
Accepted for publication 17 June 2014 Available online 9 July 2014
Positron emission tomography (PET) using 18 F-fluoro-2-deoxy-D-glucose (FDG) is well established as a useful imaging tool for the staging of squamous cell carcinoma of the head and neck.1 PET-only scanners have also largely been replaced by hybrid PET/computed tomography (PET/CT) scanners. FDG is a marker of glucose metabolism and is the most widely used radiotracer in oncological PET/CT. PET scanning has been shown to add incremental diagnostic and prognostic information in a wide range of malignancies. There is a broad correlation between the degree of FDG avidity and tumour aggressiveness and clinical prognosis. Many (but not all) types of head and neck cancer also demonstrate increased glucose metabolism, and
and pulmonary metastases, and tumourrelated deaths, it was formally reclassified as malignant by the World Health Organization in 2005.5 CCOC has a loco-regional recurrence rate of 34% for resected tumours, and a distant metastatic spread rate of 14%.2 Sites of distant metastasis are most commonly the lungs, but there have been reports of metastasis to distant bone.2,6 Despite their tendency for recurrence and capacity to metastasize, a review of the literature revealed little information regarding the glucose metabolism of these lesions or the role of FDG-PET/CT in the staging and follow-up of these aggressive tumours. We present two cases of CCOC with their relevant FDG-PET/CT findings; the
0901-5027/01101326 + 04
FDG-PET/CT scanning has proven clinical value in squamous cell carcinomas and thyroid carcinomas in particular. However there are no cases in the literature exploring its use in clear cell odontogenic carcinoma (CCOC). CCOC is a rare neoplasm; only 75 cases have been reported in the English language literature.2 It commonly presents in the fifth to seventh decades of life and disproportionately affects women.3 The anterior regions of the jaws are more frequently affected, and it is more common in the mandible than the maxilla.3 CCOC was first described by Hansen et al. as a benign separate entity.4 However, as a result of evidence of a marked tendency for local recurrence, regional lymph node
Crown Copyright # 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
FDG-PET/CT in clear cell odontogenic carcinoma first patient had primary CCOC of the mandible with FDG-avid disease, and the other had recurrence of CCOC of the anterior mandible and superomedial orbit with disease that was not FDG-avid.
Case reports Case 1
A 59-year-old woman was referred by her dentist after an incidental finding of a painless lesion of the left body of the mandible. On presentation, she also complained of paraesthesia of the left lip and chin for 2 months and a 3-kg unintentional weight loss. Physical examination revealed a firm left mandible swelling with intact mucosa and left chin and lip numbness. Cervicofacial lymph nodes were not palpable. An orthopantomogram of the mandible showed a large lytic lesion in the left hemimandible with poor margination. CT and magnetic resonance imaging (MRI) showed a left mandibular lesion that involved extensive areas of the body and anterior mandible. An incisional biopsy and immunoperoxidase stain supported the diagnosis of CCOC. The patient was referred to a tertiary hospital for further investigation and treatment. The staging FDG-PET/CT scan showed a left mandibular mass exhibiting markedly increased, slightly irregular FDG uptake (Fig. 1a). There was mild FDG uptake crossing the midline into the anterior aspect of the right body of the mandible, which raised the possibility of infiltration
across the midline. There was mild to moderate FDG uptake in bilateral level IIA neck lymph nodes possibly indicating low volume nodal metastatic disease or inflammatory changes (Fig. 1b). No evidence of distant metastasis was found. The patient underwent a left hemimandibulectomy with bilateral neck dissection and left fibula free flap reconstruction. Postoperative histopathological evaluation confirmed the diagnosis of intraosseous CCOC of the mandible. The tumour was found to have extensive involvement of soft tissues with a 39-mm depth of invasion. Surgical margins were involved and numerous perineural invasions were identified. On microscopic examination, one left level 1 neck lymph node was found to have a 5-mm tumour deposit and all other dissected lymph nodes were negative. Immunohistochemistry results further supported the diagnosis of CCOC. Currently 2 months post-procedure, the patient has commenced a 4-week course of adjuvant radiotherapy given the positive surgical margins. Case 2
The patient was a 68-year-old woman with a history of a midline anterior maxillary CCOC arising in March 2009. She underwent a maxillectomy at that stage and the defect was restored with an obturator. She was found to have a close surgical margin and underwent a subsequent procedure with no residual tumour. She had been well for 4 years postoperatively.
1327
In 2013 she presented to her local doctor with a 6-week history of paraesthesia in the left infraorbital nerve and zygomaticotemporal nerve. On examination, she was found to have watering of the left eye with normal extraocular movements and visual acuity. She had an obvious swelling over the left maxilla, lateral nasal bones, and zygoma. There was also swelling intraorally over the left maxillary alveolus with no mucosal defects found. Cervicofacial lymph nodes were not palpable. A CT scan of the head and neck showed an obvious mass in the left anterior maxilla, with local extension and bony destruction that was suspicious for recurrence. There were two other areas noted in the left posterior maxilla and a superomedial orbit lesion invading through the skull base. CT of the chest and upper abdomen showed no evidence of metastatic disease. The FDG-PET/CT scan showed markedly increased FDG uptake of the left posterior maxillary lesion (Fig. 2a). However, there was only mild FDG uptake by the left anterior maxillary lesion and superomedial orbit, which was non-specific (Fig. 2b). A biopsy of the left posterior maxilla was performed, showing an inflamed granuloma only (site of markedly increased FDG uptake), and biopsy of the left anterior maxilla (site of only mild FDG uptake) showed a recurrence of COCC. The superomedial orbital lesion was not biopsied due to its location and risks, but given CT findings was assumed to represent recurrence. The patient is currently considering radiotherapy.
Fig. 1. Case 1 FDG-PET/CT showing (a) an FDG-avid primary of the left mandible, and (b) mild to moderate FDG uptake in the bilateral level IIA neck lymph nodes.
1328
Krishnamoorthy et al.
Fig. 2. Case 2 FDG-PET/CT showing (a) an FDG-avid left posterior maxillary lesion, biopsy proven granuloma, and (b) a negative left anterior maxillary lesion and superomedial orbit, biopsy proven recurrence of CCOC.
Discussion
PET scans are commonly performed with FDG, a glucose analogue tracer. FDG enters the cell though the glucose transport proteins, where it is phosphorylated to FDG-6-phosphate, which is not further metabolized and thus trapped in the cell. Cancer cells have a higher glycolytic rate, thus take up FDG more actively than normal cells. The radioactive label fluorine-18 in the intracellularly trapped FDG decays with a half-life of 110 min by positron emission. The positrons then undergo an annihilation reaction with surrounding electrons in tissue, which creates a pair of gamma rays travelling in approximately opposite directions. These ‘annihilation events’ are detected and reconstructed to produce a PET scan image. A near contemporaneous CT scan can also be acquired in a hybrid PET/CT scanner. The CT scan is used for a PET image reconstruction process called ‘attenuation correction’, and additionally has clinical diagnostic value. The clinical application of FDG-PET/ CT in head and neck cancer mainly includes assessment of primary tumours before treatment and the assessment of recurrence and response to treatment. The FDG avidity of CCOC is unknown. In our two cases, the first patient had a left mandibular mass exhibiting markedly increased, slightly irregular FDG uptake that was later biopsy confirmed as CCOC. However, in the second case the biopsy proven CCOC malignancy of the left posterior maxilla had only mild FDG uptake. The CT scan clearly demonstrated lesions that were also later biopsy confirmed as
recurrence. This raises concern that FDGPET also has variable sensitivity to detect the metastatic spread of CCOC. FDG-PET is both more sensitive and more specific than conventional imaging in the identification of nodal metastases in other head and neck cancers. However, it is important to recognize that FDG-PET scans provide a map of glucose metabolism in the body, and all foci of FDG uptake should not be assumed to have a malignant cause. While the degree of FDG uptake may be used as a guide to the likelihood of malignancy, low tumour volumes and certain types of poorly metabolic malignancy may also show low levels of FDG uptake. ‘False-positives’ can also occur from inflammatory or infectious phenomena because aggregates of macrophages and lymphocytes demonstrate increased glucose metabolism. This was evident in our second case, where the biopsy of the FDG-avid lesion showed an inflamed granuloma. ‘False-negatives’ can occur, as lymph node micrometastases may not be detected on FDG-PET/CT scans (or any other conventional anatomical imaging modalities). In our first case, level 1 lymph nodes were not FDG-avid, although histopathology showed a small 5-mm metastasis. Large areas of acellular necrosis or lymph node proximity to the tumour can also lead to reduced FDG uptake and ‘false-negatives’. Initial imaging with FDG-PET/CT is useful in investigating regional lymph node status, distant metastases, and synchronous primaries.1 An additional benefit of FDG-PET/CT in the initial staging is that it can image the entire body as a single study and with potentially a much lower
dose of radiation than whole-body diagnostic CT.7 A literature review revealed case series and reports of CCOC where chest radiography, abdominal ultrasound, CT, and bone scans were used to investigate for metastases; however FDG-PET/CT findings have not been described in detail. Furthermore, there have been no research studies reported in the English language literature to-date investigating the efficacy of PET/CT in the staging of CCOC. Our first case demonstrated marked FDG uptake for a biopsy proven CCOC and this could mean that it may reliably identify metastases in that patient. In contrast, in our second case the low level of FDG uptake in the recurrent CCOC suggests that FDG-PET would be an unreliable tool to identify metastasis in that patient. In conclusion, while there is potential utility of FDG-PET/CT scans in the evaluation of CCOC, sensitivity appears uncertain. Although FDG-PET has proven benefits compared to other imaging modalities in other head and neck cancers, further studies are needed to investigate the role of FDG-PET/CT in CCOC. In particular, molecular studies investigating glucose metabolism in CCOC tumour cells may help explain the apparently variable FDG-PET avidity of these neoplasms. The rarity of these tumours poses a challenge and multi-centre trials or international data registries may be required. Funding
There were no study sponsors involved in the study design, in the collection, analysis
FDG-PET/CT in clear cell odontogenic carcinoma and interpretation of data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.
3.
Competing interests
There were no financial or personal relationships with other people or organizations that could inappropriately have influenced (biased) this work.
4.
5.
References 1. Wong RJ. Current status of FDG-PET for head and neck cancer. J Surg Oncol 2008;97: 649–52. 2. Kalsi AS, Williams SP, Shah KA, Fasanmade A. Clear cell odontogenic carcinoma: a rare
6.
neoplasm of the maxillary bone. J Oral Maxillofac Surg 2014;72:935–8. Li TJ, Yu SF, Gao Y, Wang EB. Clear cell odontogenic carcinoma: a clinicopathologic and immunocytochemical study of 5 cases. Arch Pathol Lab Med 2001;125: 1556–71. Hansen LS, Eversole LR, Green TL, Powell NB. Clear cell odontogenic tumor—a new histologic variant with aggressive potential. Head Neck Surg 1985;8:115–23. Barnes L, Eveson JW, Reichart P, Sidransky D. Pathology and genetics of head and neck tumours. Lyon: IARC Press; 2005: 284. Kumar M, Fasanmade A, Barret AW, Mack G, Newman L, Hyde NC. Metastasising clear cell odontogenic carcinoma: a case report and review of the literature. Oral Oncol 2003;39: 190–4.
1329
7. Duet M, Hugonnet F, Faraggi M. Role of positron emission tomography (PET) in head and neck cancer. Eur Ann Otorhinolaryngol Head Neck Dis 2010;127:40–5.
Address: Ragu Krishnamoorthy Department of Oral and Maxillofacial Surgery Gold Coast University Hospital 1 Hospital Blvd Southport Queensland 4215 Australia E-mail: [email protected]
