- Email: [email protected]
Computed Tomography Screening
Asian J Oral Maxillofac Surg. 2008;20:97-101.
Sakaki, Satoh, Kobayashi, et al
CASE REPORT
Pleomorphic Adenoma of the Palate Detected by Positron Emission Tomography/Computed Tomography Screening Hirotaka Sakaki, Hisashi Satoh, Wataru Kobayashi, Kenji Narita, Tomoaki Asano, Hiroto Kimura Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan
Abstract We report a case of pleomorphic adenoma on the left side of the hard palate detected by positron emission tomography/computed tomography. A 52-year-old woman underwent whole-body positron emission tomography examination with fluorodeoxyglucose for cancer screening at a nearby medical centre, which showed fluorodeoxyglucose uptake in the hard palate. The patient was referred to the Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan, for further evaluation. The lesion was 10 × 8 mm in size, with a clearly demarcated border, and the elastic soft mass had intact mucosa covering its surface. Preoperative magnetic resonance imaging showed a mass in the left side of the hard palate corresponding to the area on positron emission tomography/computed tomography. The clinical diagnosis was benign tumour of the palate. Surgical resection was performed under general anaesthesia. The histopathological diagnosis was pleomorphic adenoma. There have been no signs of recurrence 1 year after surgery. Key words: Adenoma, pleomorphic, Palate, Positron-emission tomography
Introduction Positron emission tomography/computed tomography (PET/ CT) scans are useful in the diagnosis and evaluation of treatment results in malignant tumours and have more recently been used for cancer screening. However, few reports have investigated the usefulness of PET/CT for imaging diagnosis of benign tumours. We describe a patient with pleomorphic adenoma of the palate that was detected by PET/ CT screening.
Case Report
Family history was unremarkable, but past medical history revealed that the patient had been receiving treatment at a local ear, nose and throat clinic for bronchial asthma since the age of 12 years and for allergic rhinitis since the age of 30. The general physical examination of the patient was unremarkable. No abnormalities were noted during the extraoral examination. However, a 10 × 8 mm lesion was noted at the posterior margin on the left side of the hard palate during intraoral examination. The mass was elastic and soft (Figure 1), had a clearly demarcated border, and was covered with normal mucosa.
The patient was a 52-year-old woman who had been referred for further evaluation of a hard palate tumour on 9 August 2005. The patient underwent whole-body positron emission tomography (PET) scan for cancer screening on 2 August 2005 at a nearby medical clinic, which had revealed abnormal fluorodeoxyglucose (FDG) uptake on the left side of the hard palate. The patient was referred to the Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan, for further evaluation and treatment. Correspondence: Hirotaka Sakaki, DDS, PhD, Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, 5-Zaifucho, Hirosaki 036-8562, Japan. Tel: (81 172) 395 127; Fax: (81 172) 395 128; E-mail: [email protected] © Asian 2008J Asian Oral Maxillofac Association Surg. of Oral Vol and 20, No Maxillofacial 2, 2008 Surgeons.
Figure 1. Intraoral photograph at initial evaluation. There is a well-demarcated mass at the posterior margin of the hard palate on the left side. 97
Screening for Pleomorphic Adenoma
a
b
c
Figure 2. Positron emission tomography/computed tomography of the head. (a) Coronal view. (b) Axial view. (c) Sagittal view. Arrowheads indicate the uptake of fluorodeoxyglucose on the left side of the palate.
PET/CT scanning revealed FDG uptake on left side of the hard palate, with a standardised uptake value (SUV) of about 3.5 (Figure 2). There was no abnormal FDG uptake in the chest, abdomen, or pelvis (Figure 3). Magnetic resonance
a
b
Figure 3. Positron emission tomography/computed tomography of the whole body (a and b). No abnormal fluorodeoxyglucose uptake is observed in the chest, abdomen, or pelvis.
a
b
imaging (MRI), performed on 30 August 2005, showed low signal intensity on T1-weighted images and a welldemarcated mass on the left side of the hard palate, measuring 10 mm in the long axis, on T2-weighted images. Signal intensity was high compared to the surrounding palatal mucosa. There was no extension into the nasal cavity (Figure 4). General laboratory tests showed no abnormal findings. Based on these findings, a clinical diagnosis of suspected benign tumour of the palate was made. The patient was admitted to the hospital on 27 September 2005. Resection of the palatal tumour was performed under general anaesthesia on 30 September 2005. The tumour was excised with a safety margin of 3 mm. The lesion was retracted and resected by electrocauterisation, with care taken not to injure the palatine artery on the left side. Although no tumour invasion into bone was observed, a layer of bone surface was removed due to the possibility of residual tumour. There was no communication with the nasal cavity after curettage of bone. Since dysarthria and dysphagia commonly develop after tumour resection in this area, we prepared a floor splint before surgery to improve articulation and swallowing. The patient began oral intake the day after surgery, had a satisfactory postoperative course, and was discharged on 10 October 2005. There have been no signs of recurrence 1 year after surgery. The patient has had a good clinical course, without development of dysarthria or dysphagia.
c
Figure 4. T2-weighted magnetic resonance imaging studies. (a) Coronal view. (b) Axial view. (c) Sagittal view. Arrowheads indicate well-demarcated areas of high signal intensity on the left side of the palate. 98
Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Sakaki, Satoh, Kobayashi, et al
The resected lesion was elastic, soft, spherical, and measured 19 × 11 × 11 mm, including the surrounding tissue. The cut surface was solid and contained red, grey and yellow tissue. No distinct capsule was identified (Figure 5). Histopathological analysis showed pleomorphic epithelial cells arranged in clumps or cords in the submucosal layer, with some irregular duct-like structures. The ductal lumen contained pink secretions. Myxomatous components stained light blue, with a foam-like coarse reticular pattern, and cord-like epithelial structures within (Figure 6). The histopathological diagnosis was pleomorphic adenoma of the palate.
Discussion PET/CT is now widely used in clinical practice, and according to a survey conducted in 2005 by the Ministry of Health, Labour and Welfare, Japan, 279 PET/CT scanners are being used at 139 medical centres throughout Japan for evaluation of various malignant tumours and for whole-body
a
cancer screening. 1 Some studies have confirmed the usefulness of PET/CT for evaluation of malignant lesions, but few reports have investigated the effectiveness of PET/ CT for evaluation of benign and inflammatory lesions. FDG uptake is not specific to malignant tumours, as occasional uptake is also seen in benign tumours and inflammatory tissue. Therefore, a potential problem with PET/CT is occasional false-positive findings when evaluating malignant tumours. Nevertheless, the high detection sensitivity of PET/ CT makes it very useful for early detection of lesions. The primary clinical manifestation of pleomorphic adenoma of the palate is a painless mass. However, if the tumour is located in the posterior palate, dysarthria and dysphagia may develop.2 Similarly, the present patient also had no subjective symptoms, and the lesion was first discovered by PET/CT screening. In general, techniques such as ultrasonography, sialography, CT, CT sialography, and/or MRI are used to evaluate salivary gland tumours. However, in minor salivary gland tumours of
a
b b
Figure 5. Resected specimen. (a) Maxillary aspect of the resected lesion shows the tumour, the safety margin of intact tissue, and the periosteum in the centre. (b) Cut surface of lesion shows a solid tumour interior. Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Figure 6. Histopathological analysis. (a) The tumour is a mixture of abundant epithelial elements and myxomatous tissue, with a capsule covered by intact mucosa (haematoxylin and eosin; original magnification, × 40). (b) Irregularly shaped duct-like structures composed of epithelial elements are present (haematoxylin and eosin; original magnification, × 100). 99
Screening for Pleomorphic Adenoma
the oral cavity, ultrasonography, sialography, and CT sialography are not feasible. In such cases, findings on CT or MRI are helpful. However, Yoshikawa et al report that for minor salivary gland tumours in the palate, CT and technetium-99m scintigraphy are not useful for deciding whether the tumour is benign or malignant.3 In these cases, gallium-67 scintigraphy may provide some information only if the primary tumour is large. Therefore, differential diagnosis using imaging studies is difficult in the evaluation of smaller, earlier lesions. In contrast to anatomic imaging studies, such as CT and MRI that are useful to evaluate, for example, tumour size and necrosis, PET/CT provides quantitative functional information about tumour glucose metabolism. Because of anatomically complex facial bones, major and minor salivary gland tissue, tortuous muscular and vascular structures, and various other spaces, imaging diagnosis of early lesions in the oral cavity and facial region is often difficult. Lesions can also be hard to delineate on CT or MRI due to artefacts, such as metal crown restorations. However, PET/CT is not affected much by these factors. In addition, PET is also ideal because there is little respiratory movement in the head and neck region. In differentiating benign from malignant lesions, FDG uptake in malignant tumours, such as oral squamous cell carcinoma is significantly higher, with a borderline SUV value of about 4.0 between benign and malignant lesions.4-6 However, in benign salivary gland tumours, such as Warthin’s tumour of the parotid gland, the degree of FDG uptake may be as high as in malignant salivary gland tumours, which is a factor that can hinder diagnosis.7,8 Thus, caution should be taken when using PET/CT alone for evaluation. Clinicians should also be aware of sites of physiological FDG uptake. In a study of normal tissues using FDG-PET and MRI, Uematsu et al found an SUV ≥ 4 in the palatine tonsils; SUV ≥ 3 in the lingual tonsils, lips, and sublingual glands; SUV ≥ 2 in the soft palate, tongue surface, gingiva, spinal cord, and hypopharynx; and SUV ≥ 1.4 in the nasal mucosa, nasopharynx, oropharynx, submandibular glands, and parotid glands.9 In another study using PET/CT, Goerres et al reported FDG uptake in lymphoid tissue (tonsils and Waldeyer’s ring at the base of tongue), salivary glands (that normally secrete glucose), genioglossus muscle, longus capitis muscle, masseter muscle, tip of the tongue, the larynx during speech, ocular muscles and eyelids in open eyes, and in bone marrow after chemotherapy. 10 Therefore, when evaluating whether FDG uptake in these sites is abnormal, a correlation with physiological uptake, differences between the left and right side, and whether uptake is higher than normal must be considered. The use of PET/CT to evaluate pleomorphic adenoma of the minor salivary glands has not yet been investigated, but the SUV for pleomorphic adenoma of the parotid gland 100
is 4.12 ± 1.82.11 Considering the correlation between SUV and tumour size, the SUV for pleomorphic adenoma of the minor salivary glands would be expected to be lower. This is consistent with the SUV of 3.5, which was observed in the present patient. The detection of an asymptomatic pleomorphic adenoma measuring 1 cm suggests that PET/CT is a highly sensitive study. In addition to clinical findings, anatomic imaging by MRI and metabolic imaging by PET can be highly useful in diagnosing and planning treatment in such patients. This report presents a case of pleomorphic adenoma of the palate that was initially detected on PET/CT and discusses some relevant literature.
Acknowledgements This study was supported in part by a Grant-in-Aid for Young Scientists (B) [No. 19791479] and a Grant-in-Aid for Scientific Research (C) [No. 19592280] from the Japan Society for Promotion of Science. An abstract of this report was presented at the 51st Annual Meeting of the Japanese Society of Oral and Maxillofacial Surgeons, Kitakyushu, Japan, in October 2006.
References 1.
Survey of medical institutions [in Japanese]. Tokyo: Ministry of Health,
2.
Chaudhry AP, Vicker RA, Gorlin RJ. Intraoral minor salivary gland
Labour and Welfare, Japan; 2005:23. tumors. An analysis of 1,414 cases. Oral Surg Oral Med Oral Pathol. 1961;14:1194-226. 3.
Yoshikawa Y, Tsubakimoto Y, Iwai S, Umehara K, Matsumura T, Amekawa S, et al. A clinical study of palatal tumors of minor salivary gland origin [article in Japanese]. J Jpn Stomatol Soc. 1997;46: 55-9.
4.
Kitagawa Y, Sadato N, Azuma H, Ogasawara T, Yoshida M, Ishii Y, et al. FDG PET to evaluate combined intra-arterial chemotherapy and radiotherapy of head and neck neoplasms. J Nucl Med. 1999;40: 1132-7.
5.
Kitagawa Y, Nishizawa S, Sano K, Ogasawara T, Nakamura M, Sadato N, et al. Prospective comparison of 18F-FDG PET with conventional imaging modalities (MRI, CT, and 67Ga scintigraphy) in assessment of combined intraarterial chemotherapy and radiotherapy for head and neck carcinoma. J Nucl Med. 2003;44:198-206.
6.
Kitagawa Y, Sano K, Nishizawa S, Nakamura M, Ogasawara T, Sadato N, et al. FDG-PET for prediction of tumour aggressiveness and response to intra-arterial chemotherapy and radiotherapy in head and neck cancer. Eur J Nucl Med Mol Imaging. 2003;30:63-71.
7.
Horiuchi M, Yasuda S, Shohtsu A, Ide M. Four cases of Warthin’s tumor of the parotid gland detected with FDG PET. Ann Nucl Med. 1998;12: 47-50.
8.
Uchida Y, Minoshima S, Kawata T, Motoori K, Nakano K, Kazama T, et al. Diagnostic value of FDG PET and salivary gland scintigraphy for parotid tumors. Clin Nucl Med. 2005;30:170-6. Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Sakaki, Satoh, Kobayashi, et al 9.
Uematsu H, Sadato N, Yonekura Y, Tsuchida T, Nakamura S, Sugimoto K, et al. Coregistration of FDG PET and MRI of the head and neck using normal distribution of FDG. J Nucl Med. 1998;39:2121-7.
10. Goerres GW, Von Schulthess GK, Hany TF. Positron emission tomography and PET CT of the head and neck: FDG uptake in normal
Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
anatomy, in benign lesions, and in changes resulting from treatment. AJR Am J Roentgenol. 2002;179:1337-43. 11. Matsuda M, Sakamoto H, Okamura T, Nakai Y, Ohashi Y, Kawabe J, et al. Positron emission tomographic imaging of pleomorphic adenoma in the parotid gland. Acta Otolaryngol Suppl. 1998;538:214-20.
101
Sakaki, Satoh, Kobayashi, et al
CASE REPORT
Pleomorphic Adenoma of the Palate Detected by Positron Emission Tomography/Computed Tomography Screening Hirotaka Sakaki, Hisashi Satoh, Wataru Kobayashi, Kenji Narita, Tomoaki Asano, Hiroto Kimura Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan
Abstract We report a case of pleomorphic adenoma on the left side of the hard palate detected by positron emission tomography/computed tomography. A 52-year-old woman underwent whole-body positron emission tomography examination with fluorodeoxyglucose for cancer screening at a nearby medical centre, which showed fluorodeoxyglucose uptake in the hard palate. The patient was referred to the Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan, for further evaluation. The lesion was 10 × 8 mm in size, with a clearly demarcated border, and the elastic soft mass had intact mucosa covering its surface. Preoperative magnetic resonance imaging showed a mass in the left side of the hard palate corresponding to the area on positron emission tomography/computed tomography. The clinical diagnosis was benign tumour of the palate. Surgical resection was performed under general anaesthesia. The histopathological diagnosis was pleomorphic adenoma. There have been no signs of recurrence 1 year after surgery. Key words: Adenoma, pleomorphic, Palate, Positron-emission tomography
Introduction Positron emission tomography/computed tomography (PET/ CT) scans are useful in the diagnosis and evaluation of treatment results in malignant tumours and have more recently been used for cancer screening. However, few reports have investigated the usefulness of PET/CT for imaging diagnosis of benign tumours. We describe a patient with pleomorphic adenoma of the palate that was detected by PET/ CT screening.
Case Report
Family history was unremarkable, but past medical history revealed that the patient had been receiving treatment at a local ear, nose and throat clinic for bronchial asthma since the age of 12 years and for allergic rhinitis since the age of 30. The general physical examination of the patient was unremarkable. No abnormalities were noted during the extraoral examination. However, a 10 × 8 mm lesion was noted at the posterior margin on the left side of the hard palate during intraoral examination. The mass was elastic and soft (Figure 1), had a clearly demarcated border, and was covered with normal mucosa.
The patient was a 52-year-old woman who had been referred for further evaluation of a hard palate tumour on 9 August 2005. The patient underwent whole-body positron emission tomography (PET) scan for cancer screening on 2 August 2005 at a nearby medical clinic, which had revealed abnormal fluorodeoxyglucose (FDG) uptake on the left side of the hard palate. The patient was referred to the Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, Hirosaki, Japan, for further evaluation and treatment. Correspondence: Hirotaka Sakaki, DDS, PhD, Department of Dentistry and Oral Surgery, Hirosaki University School of Medicine, 5-Zaifucho, Hirosaki 036-8562, Japan. Tel: (81 172) 395 127; Fax: (81 172) 395 128; E-mail: [email protected] © Asian 2008J Asian Oral Maxillofac Association Surg. of Oral Vol and 20, No Maxillofacial 2, 2008 Surgeons.
Figure 1. Intraoral photograph at initial evaluation. There is a well-demarcated mass at the posterior margin of the hard palate on the left side. 97
Screening for Pleomorphic Adenoma
a
b
c
Figure 2. Positron emission tomography/computed tomography of the head. (a) Coronal view. (b) Axial view. (c) Sagittal view. Arrowheads indicate the uptake of fluorodeoxyglucose on the left side of the palate.
PET/CT scanning revealed FDG uptake on left side of the hard palate, with a standardised uptake value (SUV) of about 3.5 (Figure 2). There was no abnormal FDG uptake in the chest, abdomen, or pelvis (Figure 3). Magnetic resonance
a
b
Figure 3. Positron emission tomography/computed tomography of the whole body (a and b). No abnormal fluorodeoxyglucose uptake is observed in the chest, abdomen, or pelvis.
a
b
imaging (MRI), performed on 30 August 2005, showed low signal intensity on T1-weighted images and a welldemarcated mass on the left side of the hard palate, measuring 10 mm in the long axis, on T2-weighted images. Signal intensity was high compared to the surrounding palatal mucosa. There was no extension into the nasal cavity (Figure 4). General laboratory tests showed no abnormal findings. Based on these findings, a clinical diagnosis of suspected benign tumour of the palate was made. The patient was admitted to the hospital on 27 September 2005. Resection of the palatal tumour was performed under general anaesthesia on 30 September 2005. The tumour was excised with a safety margin of 3 mm. The lesion was retracted and resected by electrocauterisation, with care taken not to injure the palatine artery on the left side. Although no tumour invasion into bone was observed, a layer of bone surface was removed due to the possibility of residual tumour. There was no communication with the nasal cavity after curettage of bone. Since dysarthria and dysphagia commonly develop after tumour resection in this area, we prepared a floor splint before surgery to improve articulation and swallowing. The patient began oral intake the day after surgery, had a satisfactory postoperative course, and was discharged on 10 October 2005. There have been no signs of recurrence 1 year after surgery. The patient has had a good clinical course, without development of dysarthria or dysphagia.
c
Figure 4. T2-weighted magnetic resonance imaging studies. (a) Coronal view. (b) Axial view. (c) Sagittal view. Arrowheads indicate well-demarcated areas of high signal intensity on the left side of the palate. 98
Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Sakaki, Satoh, Kobayashi, et al
The resected lesion was elastic, soft, spherical, and measured 19 × 11 × 11 mm, including the surrounding tissue. The cut surface was solid and contained red, grey and yellow tissue. No distinct capsule was identified (Figure 5). Histopathological analysis showed pleomorphic epithelial cells arranged in clumps or cords in the submucosal layer, with some irregular duct-like structures. The ductal lumen contained pink secretions. Myxomatous components stained light blue, with a foam-like coarse reticular pattern, and cord-like epithelial structures within (Figure 6). The histopathological diagnosis was pleomorphic adenoma of the palate.
Discussion PET/CT is now widely used in clinical practice, and according to a survey conducted in 2005 by the Ministry of Health, Labour and Welfare, Japan, 279 PET/CT scanners are being used at 139 medical centres throughout Japan for evaluation of various malignant tumours and for whole-body
a
cancer screening. 1 Some studies have confirmed the usefulness of PET/CT for evaluation of malignant lesions, but few reports have investigated the effectiveness of PET/ CT for evaluation of benign and inflammatory lesions. FDG uptake is not specific to malignant tumours, as occasional uptake is also seen in benign tumours and inflammatory tissue. Therefore, a potential problem with PET/CT is occasional false-positive findings when evaluating malignant tumours. Nevertheless, the high detection sensitivity of PET/ CT makes it very useful for early detection of lesions. The primary clinical manifestation of pleomorphic adenoma of the palate is a painless mass. However, if the tumour is located in the posterior palate, dysarthria and dysphagia may develop.2 Similarly, the present patient also had no subjective symptoms, and the lesion was first discovered by PET/CT screening. In general, techniques such as ultrasonography, sialography, CT, CT sialography, and/or MRI are used to evaluate salivary gland tumours. However, in minor salivary gland tumours of
a
b b
Figure 5. Resected specimen. (a) Maxillary aspect of the resected lesion shows the tumour, the safety margin of intact tissue, and the periosteum in the centre. (b) Cut surface of lesion shows a solid tumour interior. Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Figure 6. Histopathological analysis. (a) The tumour is a mixture of abundant epithelial elements and myxomatous tissue, with a capsule covered by intact mucosa (haematoxylin and eosin; original magnification, × 40). (b) Irregularly shaped duct-like structures composed of epithelial elements are present (haematoxylin and eosin; original magnification, × 100). 99
Screening for Pleomorphic Adenoma
the oral cavity, ultrasonography, sialography, and CT sialography are not feasible. In such cases, findings on CT or MRI are helpful. However, Yoshikawa et al report that for minor salivary gland tumours in the palate, CT and technetium-99m scintigraphy are not useful for deciding whether the tumour is benign or malignant.3 In these cases, gallium-67 scintigraphy may provide some information only if the primary tumour is large. Therefore, differential diagnosis using imaging studies is difficult in the evaluation of smaller, earlier lesions. In contrast to anatomic imaging studies, such as CT and MRI that are useful to evaluate, for example, tumour size and necrosis, PET/CT provides quantitative functional information about tumour glucose metabolism. Because of anatomically complex facial bones, major and minor salivary gland tissue, tortuous muscular and vascular structures, and various other spaces, imaging diagnosis of early lesions in the oral cavity and facial region is often difficult. Lesions can also be hard to delineate on CT or MRI due to artefacts, such as metal crown restorations. However, PET/CT is not affected much by these factors. In addition, PET is also ideal because there is little respiratory movement in the head and neck region. In differentiating benign from malignant lesions, FDG uptake in malignant tumours, such as oral squamous cell carcinoma is significantly higher, with a borderline SUV value of about 4.0 between benign and malignant lesions.4-6 However, in benign salivary gland tumours, such as Warthin’s tumour of the parotid gland, the degree of FDG uptake may be as high as in malignant salivary gland tumours, which is a factor that can hinder diagnosis.7,8 Thus, caution should be taken when using PET/CT alone for evaluation. Clinicians should also be aware of sites of physiological FDG uptake. In a study of normal tissues using FDG-PET and MRI, Uematsu et al found an SUV ≥ 4 in the palatine tonsils; SUV ≥ 3 in the lingual tonsils, lips, and sublingual glands; SUV ≥ 2 in the soft palate, tongue surface, gingiva, spinal cord, and hypopharynx; and SUV ≥ 1.4 in the nasal mucosa, nasopharynx, oropharynx, submandibular glands, and parotid glands.9 In another study using PET/CT, Goerres et al reported FDG uptake in lymphoid tissue (tonsils and Waldeyer’s ring at the base of tongue), salivary glands (that normally secrete glucose), genioglossus muscle, longus capitis muscle, masseter muscle, tip of the tongue, the larynx during speech, ocular muscles and eyelids in open eyes, and in bone marrow after chemotherapy. 10 Therefore, when evaluating whether FDG uptake in these sites is abnormal, a correlation with physiological uptake, differences between the left and right side, and whether uptake is higher than normal must be considered. The use of PET/CT to evaluate pleomorphic adenoma of the minor salivary glands has not yet been investigated, but the SUV for pleomorphic adenoma of the parotid gland 100
is 4.12 ± 1.82.11 Considering the correlation between SUV and tumour size, the SUV for pleomorphic adenoma of the minor salivary glands would be expected to be lower. This is consistent with the SUV of 3.5, which was observed in the present patient. The detection of an asymptomatic pleomorphic adenoma measuring 1 cm suggests that PET/CT is a highly sensitive study. In addition to clinical findings, anatomic imaging by MRI and metabolic imaging by PET can be highly useful in diagnosing and planning treatment in such patients. This report presents a case of pleomorphic adenoma of the palate that was initially detected on PET/CT and discusses some relevant literature.
Acknowledgements This study was supported in part by a Grant-in-Aid for Young Scientists (B) [No. 19791479] and a Grant-in-Aid for Scientific Research (C) [No. 19592280] from the Japan Society for Promotion of Science. An abstract of this report was presented at the 51st Annual Meeting of the Japanese Society of Oral and Maxillofacial Surgeons, Kitakyushu, Japan, in October 2006.
References 1.
Survey of medical institutions [in Japanese]. Tokyo: Ministry of Health,
2.
Chaudhry AP, Vicker RA, Gorlin RJ. Intraoral minor salivary gland
Labour and Welfare, Japan; 2005:23. tumors. An analysis of 1,414 cases. Oral Surg Oral Med Oral Pathol. 1961;14:1194-226. 3.
Yoshikawa Y, Tsubakimoto Y, Iwai S, Umehara K, Matsumura T, Amekawa S, et al. A clinical study of palatal tumors of minor salivary gland origin [article in Japanese]. J Jpn Stomatol Soc. 1997;46: 55-9.
4.
Kitagawa Y, Sadato N, Azuma H, Ogasawara T, Yoshida M, Ishii Y, et al. FDG PET to evaluate combined intra-arterial chemotherapy and radiotherapy of head and neck neoplasms. J Nucl Med. 1999;40: 1132-7.
5.
Kitagawa Y, Nishizawa S, Sano K, Ogasawara T, Nakamura M, Sadato N, et al. Prospective comparison of 18F-FDG PET with conventional imaging modalities (MRI, CT, and 67Ga scintigraphy) in assessment of combined intraarterial chemotherapy and radiotherapy for head and neck carcinoma. J Nucl Med. 2003;44:198-206.
6.
Kitagawa Y, Sano K, Nishizawa S, Nakamura M, Ogasawara T, Sadato N, et al. FDG-PET for prediction of tumour aggressiveness and response to intra-arterial chemotherapy and radiotherapy in head and neck cancer. Eur J Nucl Med Mol Imaging. 2003;30:63-71.
7.
Horiuchi M, Yasuda S, Shohtsu A, Ide M. Four cases of Warthin’s tumor of the parotid gland detected with FDG PET. Ann Nucl Med. 1998;12: 47-50.
8.
Uchida Y, Minoshima S, Kawata T, Motoori K, Nakano K, Kazama T, et al. Diagnostic value of FDG PET and salivary gland scintigraphy for parotid tumors. Clin Nucl Med. 2005;30:170-6. Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
Sakaki, Satoh, Kobayashi, et al 9.
Uematsu H, Sadato N, Yonekura Y, Tsuchida T, Nakamura S, Sugimoto K, et al. Coregistration of FDG PET and MRI of the head and neck using normal distribution of FDG. J Nucl Med. 1998;39:2121-7.
10. Goerres GW, Von Schulthess GK, Hany TF. Positron emission tomography and PET CT of the head and neck: FDG uptake in normal
Asian J Oral Maxillofac Surg. Vol 20, No 2, 2008
anatomy, in benign lesions, and in changes resulting from treatment. AJR Am J Roentgenol. 2002;179:1337-43. 11. Matsuda M, Sakamoto H, Okamura T, Nakai Y, Ohashi Y, Kawabe J, et al. Positron emission tomographic imaging of pleomorphic adenoma in the parotid gland. Acta Otolaryngol Suppl. 1998;538:214-20.
101