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CT in a patient after talc pleurodesis
Lung Cancer (2007) 58, 418—421
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/lungcan
CASE REPORT
False positive 18F-FDG-PET/CT in a patient after talc pleurodesis Hojjat Ahmadzadehfar a,∗,1, Holger Palmedo a, Holger Strunk b, Hans-J¨ urgen Biersack a, Elham Habibi a, Samer Ezziddin a a b
Department of Nuclear Medicine, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany Department of Radiology, University Hospital Bonn, Germany
Received 11 January 2007; received in revised form 17 May 2007; accepted 23 May 2007
KEYWORDS FDG; PET/CT; Pneumothorax; Talc pleurodesis; Lung cancer
Summary A 61-year-old man presented with spontaneous pneumothorax. After diagnosis of emphysemic bullae, the patient underwent talc pleurodesis and had no further complaints. Five years later a routine chest X-ray showed suspicious pleural lesions in addition to the emphysema, which was deemed compatible with the known history of talc pleurodesis. Subsequent chest CT, however, revealed one lesion in the right lung that appeared not typical for this condition in addition to multiple lesions in pleural proximity. FDG-PET/CT demonstrated high glucose uptake in all the lesions. Subsequent needle biopsy of the suspicious intrapulmonary and also of one mediastinal lesion yielded the histopathological diagnosis of talcum granuloma with long-standing calculous fibrotic changes and no evidence of malignancy. This report on PET/CT after talc pleurodesis addresses the potential pitfalls caused by this condition, as chronic granulomatous reactions, like other inflammatory lesions, may account for highly increased FDG uptake which should be interpreted with caution and not simply read as a sign of malignancy. PET/CT offers the opportunity to exactly localize the areas of increased FDG uptake within regions of pleural thickening caused by talc deposition, however, the dilemma of misleading FDG accumulation cannot be solved by this hybrid imaging modality. © 2007 Elsevier Ireland Ltd. All rights reserved.
1. Introduction During the last decade, positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) has become a clini-
∗
Corresponding author. Tel.: +49 228 287 19858; fax: +49 228 287 11016. E-mail address: [email protected] (H. Ahmadzadehfar). 1 http://www.nucmedinfo.com.
cally convincing tool in the diagnosis, staging and treatment of non-small cell lung cancer [1—5]. Worldwide guidelines for thoracic surgery recommend performance of FDG-PET mainly for lymph node staging in lung cancer. However, FDGPET is of high sensitivity (93—95%) and acceptable specificity (77—88%) in the differential diagnosis of solitary pulmonary lesions [6—9]. A source of false positive findings is found in inflammatory processes like, e.g. granuloma, tuberculosis, aspergiloma, nocardiosis. This case report presents PET/CT findings in a patient suspected to have metastatic lung cancer after talc pleurodesis.
0169-5002/$ — see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.lungcan.2007.05.015
False positive
18
F-FDG-PET/CT in a patient after talc pleurodesis
2. Case report A 61-year-old patient presented with right sided spontaneous pneumothorax in July 1999. Bullous emphysema was diagnosed at that time. The patient underwent talc pleurodesis with no other pulmonary intervention such as a wedge resection. The patient had no further complaints after this procedure. In June 2004, a routine chest X-ray showed suspicious pleural lesions and an emphysema. Subsequent chest CT showed multiple pleural, mediastinal and one intrapulmonary lesion. Some of the lesions seemed compatible with the history of talc pleurodesis performed 5 years ago. However, a lesion of two centimetres in diameter located in the lower lobe of the right lung appeared not typical for this condition (Fig. 1a). As a consequence
419
further evaluation was performed by a FDG-PET/CT scan (Siemens Biograph). FDG-PET/CT demonstrated high glucose uptake in all mentioned lesions, an exemplary image is shown in Fig. 2. Thoracic magnetic resonance imaging (MRI) (Fig. 1d) identified the right intrapulmonary lesion with an increased signal in the T2 sequence which was not consistent with inactive fribrotic tissue (scar). It also showed partial contrast enhancement in the apical part of the lesion indicative of vital tissue. The finding was read as compatible with either an inflammatory process or a benign tumor. The subsequently performed needle biopsies of the described parenchymal lung lesion (Fig. 1e and f) and a mediastinal lesion yielded a histopathology of calculous fibrotic changes consistent with talcum granuloma and no evidence of malignancy.
Fig. 1 Suspect intrapulmonary lesion (arrow) seen on the CT scan (1a), with high glucose uptake (standard uptake value, SUV mean: 1.5) seen on PET/CT (1b) and PET (1c), and increased signal in the T2 sequence in MRI (1d), needle biopsy of this lesion (1e and 1f).
420
Fig. 2 2d.
H. Ahmadzadehfar et al.
FDG-PET/CT demonstrating high glucose uptake (arrows) in mediastinal lesions, SUV mean: 9 in 2b and SUV mean: 4.8 in
Imaging studies were performed with a PET/CT scanner (Biograph; Siemens Medical Solutions, Inc.) using a 15.8 cm axial field of view and an in-plane spatial resolution of 4.6 mm. PET imaging was commenced 90 min after intravenous injection of 351 MBq of 18 F-FDG. Blood glucose measured before injection was 0.95 g/L. The acquisition time was 5 min per bed position, with six bed positions covering thorax, abdomen and pelvis. CT was performed within 1 min before PET with the patient in the same position. Attenuation correction for PET was based on rescaling of the CT image.
3. Discussion Talc pleurodesis is widely performed in the management of persistent pneumothorax and pleural effusion, in particularly malignant effusions. However, there is very few data characterizing FDG-PET/CT findings after treatment. Talc pleurodesis was first employed by Bethune in 1935 as a preoperative procedure to anchor the lung during lobectomy [10]. Since then, talc pleurodesis has been widely employed for recurrent pneumothoraces and pleural effusions with high efficiency [11—13]. A first case report on FDG uptake after talc pleurodesis has been previously published [14]. It described increased FDG accumulation that corresponded to high density plaques in the CT. The findings were attributed to talc pleurodesis. Recently, another report on FDG-PET and CT after talc pleurodesis was published [15]. Nine patients who had talc pleurodesis underwent FDG-PET scanning on average 22 months after the procedure. There was moderate to intense plaque-like or focal nodular increased FDG uptake in the pleura on PET with standardized uptake val-
ues (SUV) between 2.0 and 16.3. The FDG uptake was either diffuse (n = 2) or focal (n = 7) and most commonly occurred in the posterior costophrenic angles (n = 5), followed by the apical regions (n = 3), anterior costophrenic angel (n = 1) and the anterior chest wall (n = 1). On chest CT, these lesions corresponded to pleural thickening or nodularity with 140—380 Hounsfield units (HU). It was concluded that talc pleurodesis produces increased FDG uptake in high density areas of pleural thickening on CT. Our findings are very similar to those published by this group. It was concluded that FDG findings in the pleural space should be correlated with CT in order to identify potential pleural thickening with increased attenuation; these lesions would then suggest talc deposits rather than tumor. In this condition, chronic granulomatous reactions, like other inflammatory lesions, may account for highly increased FDG uptake. These findings of glucose hypermetabolism should be interpreted with caution and not simply misdiagnosed as malignancy. The ability of PET/CT to fuse and correlate FDG and CT findings may be helpful in differentiating malignant from talc-induced granulomatous lesions by providing the exact CT morphologic feature that matches the tracer accumulation. Allocation of hypermetabolic foci to lesions of increased density should lead to the estimated diagnosis of talc-induced granulomatous lesions in the presence of respective history. However, the core problem of misleading FDG accumulation in granulomatous tissue cannot be solved by the use of PET/CT hybrid imaging devices.
Conflict of interest None declared.
False positive
18
F-FDG-PET/CT in a patient after talc pleurodesis
References [1] Vansteenkiste Johan F. PET scan in the staging of non-small cell lung cancer. Lung Cancer 2003;42(Suppl. 1):S27—37. [2] Vansteenkiste Johan F, Stroobants Sigrid G. Positron emission tomography in the management of non-small cell lung cancer. Hematol Oncol Clin North Am 2004;18(1):269—88. [3] Halter G, Buck AK, Schirrmeister H, Aksoy E, Liewald F, Glatting G, et al. Lymph node staging in lung cancer using [18 F]FDG-PET. Thorac Cardiovasc Surg 2004;52(2):96—101. [4] Cerfolio RJ, Ojha B, Bryant AS, Bass CS, Bartalucci AA, Mountz JM. The role of FDG-PET scan in staging patients with non-small cell carcinoma. Ann Thorac Surg 2003;76(3):861—6. [5] Cheran SK, Herndon II JE, Patz EF. Comparison of whole-body FDG-PET to bone scan for detection of bone metastases in patients with a new diagnosis of lung cancer. Lung Cancer 2004;44(3):317—25. [6] Herder GJ, Golding RP, Hoekstra OS, Comans EF, Teule GJ, Postmus PE. The performance of (18)F-fluorodeoxyglucose positron emission tomography in small solitary pulmonary nodules. Eur J Nucl Med Mol Imaging 2004;31(9):1231—6. [7] Gupta NC, Maloof J, Gunel E. Probability of malignancy in solitary pulmonary nodules using fluorine-18-FDG and PET. J Nucl Med 1996;37(6):943—8.
421
[8] Dewan NA, Gupta NC, Redepenning LC, Phalen JJ, Frick MP. Diagnostic efficacy of PET-FDG imaging in solitary pulmonary nodules, potential role in evaluation and management. Chest 1993;104(4):997—1002. [9] Baldwin DR, Birchall JD, Ganatra RH, Pointon KS. Evaluation of the solitary pulmonary nodule: clinical management, role of CT and nuclear medicine. Imaging 2004;16:22—36. [10] Bethune N. Pleural poudrage, a new technique for the deliberate production of pleural adhesions as a preliminary to lobectomy. J Thorac Surg 1935;4:251—61. [11] Weissberg D, Ben-Zeev I. Talc pleurodesis, experience with 360 patients. J Thorac Cardiovasc Surg 1993;106(4):689—95. [12] Kennedy L, Sahn SA. Talc pleurodesis for the treatment of pneumothorax and pleural effusion. Chest 1994;106(4): 1215—22. [13] Rodriguez-Panadero F, Antony VB. Pleurodesis, state of the art. Eur Respir J 1997;10(7):1648—54. [14] Murray JG, Erasmus JJ, Bahtiarian EA, Goodman PC. Talc pleurodesis simulating pleural metastases on 18 Ffluorodeoxyglucose positron emission tomography. AJR 1997;168(2):359—60. [15] Kwek BH, Aquino SL, Fischman AJ. Fluorodeoxyglucose positron emission tomography and CT after talc pleurodesis. Chest 2004;125(6):2356—60.
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/lungcan
CASE REPORT
False positive 18F-FDG-PET/CT in a patient after talc pleurodesis Hojjat Ahmadzadehfar a,∗,1, Holger Palmedo a, Holger Strunk b, Hans-J¨ urgen Biersack a, Elham Habibi a, Samer Ezziddin a a b
Department of Nuclear Medicine, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany Department of Radiology, University Hospital Bonn, Germany
Received 11 January 2007; received in revised form 17 May 2007; accepted 23 May 2007
KEYWORDS FDG; PET/CT; Pneumothorax; Talc pleurodesis; Lung cancer
Summary A 61-year-old man presented with spontaneous pneumothorax. After diagnosis of emphysemic bullae, the patient underwent talc pleurodesis and had no further complaints. Five years later a routine chest X-ray showed suspicious pleural lesions in addition to the emphysema, which was deemed compatible with the known history of talc pleurodesis. Subsequent chest CT, however, revealed one lesion in the right lung that appeared not typical for this condition in addition to multiple lesions in pleural proximity. FDG-PET/CT demonstrated high glucose uptake in all the lesions. Subsequent needle biopsy of the suspicious intrapulmonary and also of one mediastinal lesion yielded the histopathological diagnosis of talcum granuloma with long-standing calculous fibrotic changes and no evidence of malignancy. This report on PET/CT after talc pleurodesis addresses the potential pitfalls caused by this condition, as chronic granulomatous reactions, like other inflammatory lesions, may account for highly increased FDG uptake which should be interpreted with caution and not simply read as a sign of malignancy. PET/CT offers the opportunity to exactly localize the areas of increased FDG uptake within regions of pleural thickening caused by talc deposition, however, the dilemma of misleading FDG accumulation cannot be solved by this hybrid imaging modality. © 2007 Elsevier Ireland Ltd. All rights reserved.
1. Introduction During the last decade, positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) has become a clini-
∗
Corresponding author. Tel.: +49 228 287 19858; fax: +49 228 287 11016. E-mail address: [email protected] (H. Ahmadzadehfar). 1 http://www.nucmedinfo.com.
cally convincing tool in the diagnosis, staging and treatment of non-small cell lung cancer [1—5]. Worldwide guidelines for thoracic surgery recommend performance of FDG-PET mainly for lymph node staging in lung cancer. However, FDGPET is of high sensitivity (93—95%) and acceptable specificity (77—88%) in the differential diagnosis of solitary pulmonary lesions [6—9]. A source of false positive findings is found in inflammatory processes like, e.g. granuloma, tuberculosis, aspergiloma, nocardiosis. This case report presents PET/CT findings in a patient suspected to have metastatic lung cancer after talc pleurodesis.
0169-5002/$ — see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.lungcan.2007.05.015
False positive
18
F-FDG-PET/CT in a patient after talc pleurodesis
2. Case report A 61-year-old patient presented with right sided spontaneous pneumothorax in July 1999. Bullous emphysema was diagnosed at that time. The patient underwent talc pleurodesis with no other pulmonary intervention such as a wedge resection. The patient had no further complaints after this procedure. In June 2004, a routine chest X-ray showed suspicious pleural lesions and an emphysema. Subsequent chest CT showed multiple pleural, mediastinal and one intrapulmonary lesion. Some of the lesions seemed compatible with the history of talc pleurodesis performed 5 years ago. However, a lesion of two centimetres in diameter located in the lower lobe of the right lung appeared not typical for this condition (Fig. 1a). As a consequence
419
further evaluation was performed by a FDG-PET/CT scan (Siemens Biograph). FDG-PET/CT demonstrated high glucose uptake in all mentioned lesions, an exemplary image is shown in Fig. 2. Thoracic magnetic resonance imaging (MRI) (Fig. 1d) identified the right intrapulmonary lesion with an increased signal in the T2 sequence which was not consistent with inactive fribrotic tissue (scar). It also showed partial contrast enhancement in the apical part of the lesion indicative of vital tissue. The finding was read as compatible with either an inflammatory process or a benign tumor. The subsequently performed needle biopsies of the described parenchymal lung lesion (Fig. 1e and f) and a mediastinal lesion yielded a histopathology of calculous fibrotic changes consistent with talcum granuloma and no evidence of malignancy.
Fig. 1 Suspect intrapulmonary lesion (arrow) seen on the CT scan (1a), with high glucose uptake (standard uptake value, SUV mean: 1.5) seen on PET/CT (1b) and PET (1c), and increased signal in the T2 sequence in MRI (1d), needle biopsy of this lesion (1e and 1f).
420
Fig. 2 2d.
H. Ahmadzadehfar et al.
FDG-PET/CT demonstrating high glucose uptake (arrows) in mediastinal lesions, SUV mean: 9 in 2b and SUV mean: 4.8 in
Imaging studies were performed with a PET/CT scanner (Biograph; Siemens Medical Solutions, Inc.) using a 15.8 cm axial field of view and an in-plane spatial resolution of 4.6 mm. PET imaging was commenced 90 min after intravenous injection of 351 MBq of 18 F-FDG. Blood glucose measured before injection was 0.95 g/L. The acquisition time was 5 min per bed position, with six bed positions covering thorax, abdomen and pelvis. CT was performed within 1 min before PET with the patient in the same position. Attenuation correction for PET was based on rescaling of the CT image.
3. Discussion Talc pleurodesis is widely performed in the management of persistent pneumothorax and pleural effusion, in particularly malignant effusions. However, there is very few data characterizing FDG-PET/CT findings after treatment. Talc pleurodesis was first employed by Bethune in 1935 as a preoperative procedure to anchor the lung during lobectomy [10]. Since then, talc pleurodesis has been widely employed for recurrent pneumothoraces and pleural effusions with high efficiency [11—13]. A first case report on FDG uptake after talc pleurodesis has been previously published [14]. It described increased FDG accumulation that corresponded to high density plaques in the CT. The findings were attributed to talc pleurodesis. Recently, another report on FDG-PET and CT after talc pleurodesis was published [15]. Nine patients who had talc pleurodesis underwent FDG-PET scanning on average 22 months after the procedure. There was moderate to intense plaque-like or focal nodular increased FDG uptake in the pleura on PET with standardized uptake val-
ues (SUV) between 2.0 and 16.3. The FDG uptake was either diffuse (n = 2) or focal (n = 7) and most commonly occurred in the posterior costophrenic angles (n = 5), followed by the apical regions (n = 3), anterior costophrenic angel (n = 1) and the anterior chest wall (n = 1). On chest CT, these lesions corresponded to pleural thickening or nodularity with 140—380 Hounsfield units (HU). It was concluded that talc pleurodesis produces increased FDG uptake in high density areas of pleural thickening on CT. Our findings are very similar to those published by this group. It was concluded that FDG findings in the pleural space should be correlated with CT in order to identify potential pleural thickening with increased attenuation; these lesions would then suggest talc deposits rather than tumor. In this condition, chronic granulomatous reactions, like other inflammatory lesions, may account for highly increased FDG uptake. These findings of glucose hypermetabolism should be interpreted with caution and not simply misdiagnosed as malignancy. The ability of PET/CT to fuse and correlate FDG and CT findings may be helpful in differentiating malignant from talc-induced granulomatous lesions by providing the exact CT morphologic feature that matches the tracer accumulation. Allocation of hypermetabolic foci to lesions of increased density should lead to the estimated diagnosis of talc-induced granulomatous lesions in the presence of respective history. However, the core problem of misleading FDG accumulation in granulomatous tissue cannot be solved by the use of PET/CT hybrid imaging devices.
Conflict of interest None declared.
False positive
18
F-FDG-PET/CT in a patient after talc pleurodesis
References [1] Vansteenkiste Johan F. PET scan in the staging of non-small cell lung cancer. Lung Cancer 2003;42(Suppl. 1):S27—37. [2] Vansteenkiste Johan F, Stroobants Sigrid G. Positron emission tomography in the management of non-small cell lung cancer. Hematol Oncol Clin North Am 2004;18(1):269—88. [3] Halter G, Buck AK, Schirrmeister H, Aksoy E, Liewald F, Glatting G, et al. Lymph node staging in lung cancer using [18 F]FDG-PET. Thorac Cardiovasc Surg 2004;52(2):96—101. [4] Cerfolio RJ, Ojha B, Bryant AS, Bass CS, Bartalucci AA, Mountz JM. The role of FDG-PET scan in staging patients with non-small cell carcinoma. Ann Thorac Surg 2003;76(3):861—6. [5] Cheran SK, Herndon II JE, Patz EF. Comparison of whole-body FDG-PET to bone scan for detection of bone metastases in patients with a new diagnosis of lung cancer. Lung Cancer 2004;44(3):317—25. [6] Herder GJ, Golding RP, Hoekstra OS, Comans EF, Teule GJ, Postmus PE. The performance of (18)F-fluorodeoxyglucose positron emission tomography in small solitary pulmonary nodules. Eur J Nucl Med Mol Imaging 2004;31(9):1231—6. [7] Gupta NC, Maloof J, Gunel E. Probability of malignancy in solitary pulmonary nodules using fluorine-18-FDG and PET. J Nucl Med 1996;37(6):943—8.
421
[8] Dewan NA, Gupta NC, Redepenning LC, Phalen JJ, Frick MP. Diagnostic efficacy of PET-FDG imaging in solitary pulmonary nodules, potential role in evaluation and management. Chest 1993;104(4):997—1002. [9] Baldwin DR, Birchall JD, Ganatra RH, Pointon KS. Evaluation of the solitary pulmonary nodule: clinical management, role of CT and nuclear medicine. Imaging 2004;16:22—36. [10] Bethune N. Pleural poudrage, a new technique for the deliberate production of pleural adhesions as a preliminary to lobectomy. J Thorac Surg 1935;4:251—61. [11] Weissberg D, Ben-Zeev I. Talc pleurodesis, experience with 360 patients. J Thorac Cardiovasc Surg 1993;106(4):689—95. [12] Kennedy L, Sahn SA. Talc pleurodesis for the treatment of pneumothorax and pleural effusion. Chest 1994;106(4): 1215—22. [13] Rodriguez-Panadero F, Antony VB. Pleurodesis, state of the art. Eur Respir J 1997;10(7):1648—54. [14] Murray JG, Erasmus JJ, Bahtiarian EA, Goodman PC. Talc pleurodesis simulating pleural metastases on 18 Ffluorodeoxyglucose positron emission tomography. AJR 1997;168(2):359—60. [15] Kwek BH, Aquino SL, Fischman AJ. Fluorodeoxyglucose positron emission tomography and CT after talc pleurodesis. Chest 2004;125(6):2356—60.