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Radiologically-guided cutting needle biopsy for suspected malignancy in childhood
Clinical Radiology(1993) 48, 236 240
Radiologically-Guided Cutting Needle Biopsy for Suspected Malignancy in Childhood J. M. SOMERS, D. J. LOMAS, J. C. H A C K I N G , N. C O L E M A N * , V. A. B R O A D B E N T t and A. K. D I X O N
Departments of Radiology, *Histopathology and ~Paediatric Oncology, Addenbrooke's Hospital and the University of Cambridge, Cambridge Twenty-seven cutting needle biopsies were performed on 25 children with suspected malignancy using computed tomographic (CT, 22) or ultrasound (US, 5) guidance. Anatomical sites were: retroperitoneum 6, liver 4, kidney 4, abdomen/pelvis 4, thorax 4, bowel 2, neck 1. Sixteen patients (64 %) underwent subsequent open biopsy (5), marrow biopsy (2) or resection (9). There was complete concordance between the histological findings from the open or marrow biopsy and the previous needle biopsy in 12 of these 16 patients; in two patients the needle biopsy was misleading, causing inappropriate initial treatment in one. In two other patients needle biopsy was correct but lacked specific diagnostic features. Needle biopsies were performed under general, local or Ketamine anaesthesia. There were no apparent complications related to these procedures. We believe that radiologically-guided cutting needle biopsy should replace open biopsy in most children with solid malignant lesions. It can easily be performed during a single anaesthetic episode which allows radiological evaluation, biopsy, bone marrow and cerebrospinai fluid sampling. However, the potential for sampling error and histological variation within these tumours needs to be borne in mind. Somers, J.M., Lomas, D.J., Hacking, J.C., Coleman, N., Broadbent, V.A. & Dixon, A.K. (1993). Clinical Radiology 48, 236-240. RadiologicallyGuided Cutting Needle Biopsy for Suspected Malignancy in Childhood
Accepted for Publication 19 April 1993
Radiologically-guided needle biopsy is now an established procedure in adult oncological practice [1]. It is quick [2], and carries virtually no morbidity [3]. Open biopsy has been the practice for suspected malignancy in the paediatric age group, with the exception of inoperable Wilms' tumour, where diagnostic cutting needle biopsies are taken before starting chemotherapy [4]. Even in this latter situation biopsies are often performed as a surgical rather than a radiological procedure, and without direct image guidance [5]. Since 1981 there have been several reports suggesting that biopsy procedures may also be effective in children [6-11]. In our institution we have been relying increasingly on this technique for initial diagnosis. In this article we present our experience of radiologically-guided cutting needle biopsy for suspected malignancy at Addenbrooke's Hospital, Cambridge, which is a regional paediatric oncology centre. P A T I E N T S AND M E T H O D S Between 1983 and 1992, 25 patients with suspected solid malignancies underwent radiologically-guided cutting needle biopsy. The patients' ages ranged from 12 months to 16 years (mean = 6 years 7 months, median--4 years l0 months). Two patients underwent a second biopsy (vide infra) totalling 27 procedm'es in all. All biopsies were performed by a radiologist under either computed tomographic (CT) or ultrasound (US) control. The majority of biopsies (22) were performed under CT control, usually at the end of the initial diagnostic and staging investigation. US guidance was Correspondence to: J. M. Somers, Radiology Department, City Hospital, Hucknall Road, Nottingham NG5 1PB.
used in five patients with large tumours where access was relatively straightforward. These biopsies were performed as a separate procedure following discussion and careful evaluation of the CT appearances. General anaesthesia was employed on 10 occasions (37%) and local anaesthesia on l0 occasions (37%), the latter usually in older and more cooperative patients. Seven biopsies (26%) were performed under Ketamine anaesthesia. The method of biopsy is identical to that used in adult practice. Full consent for anaesthesia and biopsy needs to be obtained from the parent or guardian and the child prepared as for a surgical procedure. Following diagnostic CT, a slice is selected which allows access to the tumour percutaneously whilst avoiding structures such as bowel, blood vessels or other organs. For this purpose enhancement of vessels with intravenous contrast medium is required. The projected site of entry is marked on the skin using the light beam on the CT machine and checked with a needle (e.g. for local anaesthetic) placed in the subcutaneous tissues. For likely retroperitoneal tumours a prone approach may be necessary. The biopsy needle is then inserted to a predetermined depth as judged from the CT images and making allowance for the travel of the needle during biopsy. The patient is rescanned to ensure the needle is in the correct position and the biopsy is then taken (Fig. 1). This can be repeated until adequate samples have been obtained. All biopsies were taken using cutting needles. The two earliest biopsies used a manually operated 14 gauge 'Trucut' needle. All other biopsies (1989 onwards) were taken with a powered biopsy device (BioptyTM)using. 18 or 20 gauge cutting needles. As a minimum, two biopsy cores were taken and sent fresh to the Department of Histopathology. All biopsies were retrospectively reviewed by
BIOPSY FOR PAEDIATRIC MALIGNANCY
(a)
237
Fig. 2 A C T section through the pelvis demonstrating a solid mass intimately related to small bowel. The tip of the biopsy needle is demonstrated in good position for biopsy (arrow). Histology revealed only inflammatory tissue. A repeat needle biopsy yielded the same result. Subsequent open biopsy revealed an inflammatory mass around a loop of ileum with no evidence of malignancy. The mass subsided with conservative treatment and the patient remains well.
DISCUSSION
(b) Fig. l - ( a ) A C T section through the upper abdomen demonstrating ascites and a large heterogeneously-enhancing but largely fluid dense mass on the left. This was shown to be separate from the liver, adrenal and left kidney. The mass was considered to be extensively necrotic and unsuitable for needle biopsy at this level. (b) An inferior section at the level o f the pancreas shows a solid lesion suitable for biopsy. The needle tip is shown in good position for biopsy (arrow). A needle biopsy diagnosis of embryonal rhabdomyosarcoma was obtained. This result was confirmed at subsequent resection; the t u m o u r was arising from the omentum.
one histopathologist (NC) and assessed for diagnostic quality (Tables 1 3). Bone marrow and fluid samples for flow cytometry were also taken where appropriate during the same anaesthetic episode. The patient returned to the ward for at least 24 h. Routine observations were recorded after the procedure; these varied according to the anatomical site of the biopsy.
RESULTS The results together with histopathological assessment of the biopsy samples are given in Tables 1-3. There was no mortality and no apparent morbidity associated with the procedures.
One of the major goals in paediatric oncology is to obtain an accurate diagnosis as quickly as possible with the minimum morbidity to the patient. For solid malignant lesions outside the central nervous system, initial clinical, laboratory and radiological investigation has conventionally been followed by an open surgical biopsy for tissue diagnosis. This will necessarily entail some delay and morbidity. Radiologically-guided needle biopsy provides several advantages. It can be performed as part of the initial radiological diagnostic investigation, thus saving time. Image guidance allows the selection of more solid parts of the tumour for biopsy, avoiding cystic, and therefore probable necrotic areas (Fig. 1). The use of modern powered biopsy 'guns' or spring-loaded needles reduces crush artefact compared with hand-operated cutting needles and allows the use of smaller gauge needles [6]. This in turn leads to a reduction in morbidity which was insignificant in this and other series [7-11]. Samples provided are cores of tissue suitable for histology, immunocytochemistry and electron microscopy. Other biological variables including oncogene analysis and cytogenetics were not readily available at this centre during the period of the study. These variables are becoming increasingly important to differentiate between various histologically similar small round cell tumours of childhood. It remains to be seen whether small core biopsies are suitable for such studies, but it would seem that accurate image guidance to obtain the best possible core biopsies will be of even greater importance. Many biopsies can be performed without formal general anaesthesia, particularly in older children. However, a group from Germany obtained excellent results using only local anaesthesia for all ages [4]. We have found the anaesthetic agent Ketamine particularly useful since it provides general anaesthesia whilst maintaining the airway and spontaneous respiration. In 84% of patients in this series the results of needle biopsy either allowed treatment to commence without open biopsy (9) or were in complete agreement with
238
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nancy, possibly lymphoma. Needle biopsy (Fig. 2) on two occasions revealed only inflammatory tissue, which was confirmed by subsequent open biopsy and follow-up with radiological resolution on conservative treatment. This illustrates the problem of accepting a non-specific negative biopsy where malignancy is suspected. This is a difficult area for the clinician who may be obliged, as in this patient, to elect for open biopsy rather than run the considerable risk of missing a diagnosis such as lymphoma [1]. The four cases of incomplete concordance between needle and open biopsy can be attributed to unrepresentative sampling (Table 2). In two patients, undifferentiated sarcoma and mediastinal Hodgkin's disease, the lack of specificity was recognized and led directly to open biopsy. In the third case, a good biopsy sample was thought to be consistent with Wilms' tumour. This was fully in keeping with the clinical and radiological findings. However, the tumour failed to regress and subsequent nephrectomy revealed the correct diagnosis of the rare bone metastasizing renal tumour of childhood. The original biopsy did not, even on review, show any features diagnostic of this tumour and had presumably missed the relevant areas which were elsewhere within the tumour mass. The fourth incomplete diagnosis illustrates variation o f histology encountered in malignant small cell tumours of childhood. Biopsies of a retroperitoneal mass showed unequivocal differentiated ganglioneuroma (Fig. 3). Marrow samples taken at the same time as the needle biopsy revealed neuroblastoma. Thus the patient did not require surgical biopsy of the primary mass. Neuroblastoma is noted for its ability for benign differentiated ganglioneuromatous elements to co-exist with undifferentiated neuroblastoma within the same tumour [ 12,13]. While sampling error can be reduced by taking multiple biopsy samples from carefully selected sites, it cannot be completely abolished. It is important to assess the histological result together with all other diagnostic information when reaching the final diagnosis. It should be noted, however, that no case of malignant disease was missed and in only one case did biopsy sampling error lead to initial incorrect management, namely the bone metastasizing turnout of childhood. We believe that radiologically-guided cutting needle biopsy can replace surgical open biopsy for most solid malignant tumours outside the central nervous system in children. In our institution it has already done so. REFERENCES
(c) Fig. 3 - (a) CT in the supine position demonstrating a right paraspinal, retrocrural mass which is infiltrating the spinal canal (arrow) and is typical for neuroblastoma. (b) CT in the prone position demonstrating the needle tip within the mass prior to biopsy (arrow). (c) Histology from the needle biopsy ( • l0 objective lens) shows a mixture of elongated cells with wavy nuclei and fibrillary cytoplasm, and large ganglion cells, with oval nuclei, containing occasional nucleoli (arrow). No undifferentiated elements are present. There was widespread expression ofneurofilament protein (not shown). Appearances are those of a ganglioneuroma. Marrow samples, however, revealed malignant small round cells typical of neuroblastoma.
subsequent open biopsy (3), marrow biopsy (1) or resection (8). In only one patient was an open biopsy carried out because the needle biopsy was thought to be incorrect. In this patient a mass adjacent to the small bowel was considered to be highly suspicious of malig-
1 Husband JE, Golding SJ. The role of computed tomography-guided needle biopsy in an oncology service. Clinical Radiology 1983;34:255 260. 2 Lomas D J, Dixon AK. The duration of interventional procedures using computed tomographic guidance. Journal of Interventional Radiology 1990; 1:13- l 5. 3 Welch T J, Sheedy PF, Johnson CD, Johnson CM, Stephens DH. CT-guided biopsy: prospective analysis of I000 procedures. Radiology 1989;171:493~[96. 4 Saarinen UM, Wilkstrom S, Koskimies O, Sariola H. Percutaneous needle biopsy preceding preoperative chemotherapy in the management of massive renal tumours in children. Journal of Clinical Oncology 1991;9:406-415. 5 Dykes EH, Marwaha RK, Dicks-Mireaux C, Sams V, Risdon RA, Duffy PG, Ransley PG, Pfitchard J. Risks and benefits of percutaneous biopsy and primary chemotherapy in advanced Wilms' Turnout. Journal of Pediatric Surgery 1991;26:610 612. 6 Poster RB, Jones DB, Spirt BA. Percutaneous pediatric renal biopsy: use of the Biopty gun. Radiology 1990;176:725-727.
240
CLINICAL RADIOLOGY
7 Klose KC, Mertens R, Alzen G, Loer F, Bocking A. CT-guided percutaneous large-bore biopsies in benign and malignant pediatric lesions. Cardiovascular andlnterventional Radiology 1991;14:78 83. 8 Rosenberg HK, Sherman NH. Ultrasound guidance for interventional and intraoperative techniques in infants and children. Clinical Pediatrics 1990;29:457-463. 9 Hoffer FA, Kozakewich H, Shamberger RC. Percutaneous biopsy of thoracic lesions in children. Cardiovascular and Interventional Radiology 1990;13:32-35. 10 Towbin RB, Strife JL. Percutaneous aspiration, drainage, and biopsies in children~ Radiology 1985; 157:81-85.
11 Sabbah R, Ghandour M, Ali A, Lewall D. Tru-cut needle biopsy of abdominal tumours in children: a safe and diagnostic procedure. Cancer 1981;47:2533-2535. 12 Hughes M, Marsden MB, Palmer MK. Histologic patterns of neuroblastoma related to prognosis and clinical staging. Cancer 1974;34:1706-1711. 13 Shimada H, Chatten J, Newton WA Jr, Sachs N, Hamoudi AB, Chiba T et al. Histopathologic prognostic factors in neuroblastic tumors: definition of subtypes of ganglioneuroblastoma and an agelinked classification of neuroblastomas. Journal of the National Cancer Institute 1984;73:405-413.
Radiologically-Guided Cutting Needle Biopsy for Suspected Malignancy in Childhood J. M. SOMERS, D. J. LOMAS, J. C. H A C K I N G , N. C O L E M A N * , V. A. B R O A D B E N T t and A. K. D I X O N
Departments of Radiology, *Histopathology and ~Paediatric Oncology, Addenbrooke's Hospital and the University of Cambridge, Cambridge Twenty-seven cutting needle biopsies were performed on 25 children with suspected malignancy using computed tomographic (CT, 22) or ultrasound (US, 5) guidance. Anatomical sites were: retroperitoneum 6, liver 4, kidney 4, abdomen/pelvis 4, thorax 4, bowel 2, neck 1. Sixteen patients (64 %) underwent subsequent open biopsy (5), marrow biopsy (2) or resection (9). There was complete concordance between the histological findings from the open or marrow biopsy and the previous needle biopsy in 12 of these 16 patients; in two patients the needle biopsy was misleading, causing inappropriate initial treatment in one. In two other patients needle biopsy was correct but lacked specific diagnostic features. Needle biopsies were performed under general, local or Ketamine anaesthesia. There were no apparent complications related to these procedures. We believe that radiologically-guided cutting needle biopsy should replace open biopsy in most children with solid malignant lesions. It can easily be performed during a single anaesthetic episode which allows radiological evaluation, biopsy, bone marrow and cerebrospinai fluid sampling. However, the potential for sampling error and histological variation within these tumours needs to be borne in mind. Somers, J.M., Lomas, D.J., Hacking, J.C., Coleman, N., Broadbent, V.A. & Dixon, A.K. (1993). Clinical Radiology 48, 236-240. RadiologicallyGuided Cutting Needle Biopsy for Suspected Malignancy in Childhood
Accepted for Publication 19 April 1993
Radiologically-guided needle biopsy is now an established procedure in adult oncological practice [1]. It is quick [2], and carries virtually no morbidity [3]. Open biopsy has been the practice for suspected malignancy in the paediatric age group, with the exception of inoperable Wilms' tumour, where diagnostic cutting needle biopsies are taken before starting chemotherapy [4]. Even in this latter situation biopsies are often performed as a surgical rather than a radiological procedure, and without direct image guidance [5]. Since 1981 there have been several reports suggesting that biopsy procedures may also be effective in children [6-11]. In our institution we have been relying increasingly on this technique for initial diagnosis. In this article we present our experience of radiologically-guided cutting needle biopsy for suspected malignancy at Addenbrooke's Hospital, Cambridge, which is a regional paediatric oncology centre. P A T I E N T S AND M E T H O D S Between 1983 and 1992, 25 patients with suspected solid malignancies underwent radiologically-guided cutting needle biopsy. The patients' ages ranged from 12 months to 16 years (mean = 6 years 7 months, median--4 years l0 months). Two patients underwent a second biopsy (vide infra) totalling 27 procedm'es in all. All biopsies were performed by a radiologist under either computed tomographic (CT) or ultrasound (US) control. The majority of biopsies (22) were performed under CT control, usually at the end of the initial diagnostic and staging investigation. US guidance was Correspondence to: J. M. Somers, Radiology Department, City Hospital, Hucknall Road, Nottingham NG5 1PB.
used in five patients with large tumours where access was relatively straightforward. These biopsies were performed as a separate procedure following discussion and careful evaluation of the CT appearances. General anaesthesia was employed on 10 occasions (37%) and local anaesthesia on l0 occasions (37%), the latter usually in older and more cooperative patients. Seven biopsies (26%) were performed under Ketamine anaesthesia. The method of biopsy is identical to that used in adult practice. Full consent for anaesthesia and biopsy needs to be obtained from the parent or guardian and the child prepared as for a surgical procedure. Following diagnostic CT, a slice is selected which allows access to the tumour percutaneously whilst avoiding structures such as bowel, blood vessels or other organs. For this purpose enhancement of vessels with intravenous contrast medium is required. The projected site of entry is marked on the skin using the light beam on the CT machine and checked with a needle (e.g. for local anaesthetic) placed in the subcutaneous tissues. For likely retroperitoneal tumours a prone approach may be necessary. The biopsy needle is then inserted to a predetermined depth as judged from the CT images and making allowance for the travel of the needle during biopsy. The patient is rescanned to ensure the needle is in the correct position and the biopsy is then taken (Fig. 1). This can be repeated until adequate samples have been obtained. All biopsies were taken using cutting needles. The two earliest biopsies used a manually operated 14 gauge 'Trucut' needle. All other biopsies (1989 onwards) were taken with a powered biopsy device (BioptyTM)using. 18 or 20 gauge cutting needles. As a minimum, two biopsy cores were taken and sent fresh to the Department of Histopathology. All biopsies were retrospectively reviewed by
BIOPSY FOR PAEDIATRIC MALIGNANCY
(a)
237
Fig. 2 A C T section through the pelvis demonstrating a solid mass intimately related to small bowel. The tip of the biopsy needle is demonstrated in good position for biopsy (arrow). Histology revealed only inflammatory tissue. A repeat needle biopsy yielded the same result. Subsequent open biopsy revealed an inflammatory mass around a loop of ileum with no evidence of malignancy. The mass subsided with conservative treatment and the patient remains well.
DISCUSSION
(b) Fig. l - ( a ) A C T section through the upper abdomen demonstrating ascites and a large heterogeneously-enhancing but largely fluid dense mass on the left. This was shown to be separate from the liver, adrenal and left kidney. The mass was considered to be extensively necrotic and unsuitable for needle biopsy at this level. (b) An inferior section at the level o f the pancreas shows a solid lesion suitable for biopsy. The needle tip is shown in good position for biopsy (arrow). A needle biopsy diagnosis of embryonal rhabdomyosarcoma was obtained. This result was confirmed at subsequent resection; the t u m o u r was arising from the omentum.
one histopathologist (NC) and assessed for diagnostic quality (Tables 1 3). Bone marrow and fluid samples for flow cytometry were also taken where appropriate during the same anaesthetic episode. The patient returned to the ward for at least 24 h. Routine observations were recorded after the procedure; these varied according to the anatomical site of the biopsy.
RESULTS The results together with histopathological assessment of the biopsy samples are given in Tables 1-3. There was no mortality and no apparent morbidity associated with the procedures.
One of the major goals in paediatric oncology is to obtain an accurate diagnosis as quickly as possible with the minimum morbidity to the patient. For solid malignant lesions outside the central nervous system, initial clinical, laboratory and radiological investigation has conventionally been followed by an open surgical biopsy for tissue diagnosis. This will necessarily entail some delay and morbidity. Radiologically-guided needle biopsy provides several advantages. It can be performed as part of the initial radiological diagnostic investigation, thus saving time. Image guidance allows the selection of more solid parts of the tumour for biopsy, avoiding cystic, and therefore probable necrotic areas (Fig. 1). The use of modern powered biopsy 'guns' or spring-loaded needles reduces crush artefact compared with hand-operated cutting needles and allows the use of smaller gauge needles [6]. This in turn leads to a reduction in morbidity which was insignificant in this and other series [7-11]. Samples provided are cores of tissue suitable for histology, immunocytochemistry and electron microscopy. Other biological variables including oncogene analysis and cytogenetics were not readily available at this centre during the period of the study. These variables are becoming increasingly important to differentiate between various histologically similar small round cell tumours of childhood. It remains to be seen whether small core biopsies are suitable for such studies, but it would seem that accurate image guidance to obtain the best possible core biopsies will be of even greater importance. Many biopsies can be performed without formal general anaesthesia, particularly in older children. However, a group from Germany obtained excellent results using only local anaesthesia for all ages [4]. We have found the anaesthetic agent Ketamine particularly useful since it provides general anaesthesia whilst maintaining the airway and spontaneous respiration. In 84% of patients in this series the results of needle biopsy either allowed treatment to commence without open biopsy (9) or were in complete agreement with
238
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BIOPSY FOR PAEDIATRIC MALIGNANCY
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239
nancy, possibly lymphoma. Needle biopsy (Fig. 2) on two occasions revealed only inflammatory tissue, which was confirmed by subsequent open biopsy and follow-up with radiological resolution on conservative treatment. This illustrates the problem of accepting a non-specific negative biopsy where malignancy is suspected. This is a difficult area for the clinician who may be obliged, as in this patient, to elect for open biopsy rather than run the considerable risk of missing a diagnosis such as lymphoma [1]. The four cases of incomplete concordance between needle and open biopsy can be attributed to unrepresentative sampling (Table 2). In two patients, undifferentiated sarcoma and mediastinal Hodgkin's disease, the lack of specificity was recognized and led directly to open biopsy. In the third case, a good biopsy sample was thought to be consistent with Wilms' tumour. This was fully in keeping with the clinical and radiological findings. However, the tumour failed to regress and subsequent nephrectomy revealed the correct diagnosis of the rare bone metastasizing renal tumour of childhood. The original biopsy did not, even on review, show any features diagnostic of this tumour and had presumably missed the relevant areas which were elsewhere within the tumour mass. The fourth incomplete diagnosis illustrates variation o f histology encountered in malignant small cell tumours of childhood. Biopsies of a retroperitoneal mass showed unequivocal differentiated ganglioneuroma (Fig. 3). Marrow samples taken at the same time as the needle biopsy revealed neuroblastoma. Thus the patient did not require surgical biopsy of the primary mass. Neuroblastoma is noted for its ability for benign differentiated ganglioneuromatous elements to co-exist with undifferentiated neuroblastoma within the same tumour [ 12,13]. While sampling error can be reduced by taking multiple biopsy samples from carefully selected sites, it cannot be completely abolished. It is important to assess the histological result together with all other diagnostic information when reaching the final diagnosis. It should be noted, however, that no case of malignant disease was missed and in only one case did biopsy sampling error lead to initial incorrect management, namely the bone metastasizing turnout of childhood. We believe that radiologically-guided cutting needle biopsy can replace surgical open biopsy for most solid malignant tumours outside the central nervous system in children. In our institution it has already done so. REFERENCES
(c) Fig. 3 - (a) CT in the supine position demonstrating a right paraspinal, retrocrural mass which is infiltrating the spinal canal (arrow) and is typical for neuroblastoma. (b) CT in the prone position demonstrating the needle tip within the mass prior to biopsy (arrow). (c) Histology from the needle biopsy ( • l0 objective lens) shows a mixture of elongated cells with wavy nuclei and fibrillary cytoplasm, and large ganglion cells, with oval nuclei, containing occasional nucleoli (arrow). No undifferentiated elements are present. There was widespread expression ofneurofilament protein (not shown). Appearances are those of a ganglioneuroma. Marrow samples, however, revealed malignant small round cells typical of neuroblastoma.
subsequent open biopsy (3), marrow biopsy (1) or resection (8). In only one patient was an open biopsy carried out because the needle biopsy was thought to be incorrect. In this patient a mass adjacent to the small bowel was considered to be highly suspicious of malig-
1 Husband JE, Golding SJ. The role of computed tomography-guided needle biopsy in an oncology service. Clinical Radiology 1983;34:255 260. 2 Lomas D J, Dixon AK. The duration of interventional procedures using computed tomographic guidance. Journal of Interventional Radiology 1990; 1:13- l 5. 3 Welch T J, Sheedy PF, Johnson CD, Johnson CM, Stephens DH. CT-guided biopsy: prospective analysis of I000 procedures. Radiology 1989;171:493~[96. 4 Saarinen UM, Wilkstrom S, Koskimies O, Sariola H. Percutaneous needle biopsy preceding preoperative chemotherapy in the management of massive renal tumours in children. Journal of Clinical Oncology 1991;9:406-415. 5 Dykes EH, Marwaha RK, Dicks-Mireaux C, Sams V, Risdon RA, Duffy PG, Ransley PG, Pfitchard J. Risks and benefits of percutaneous biopsy and primary chemotherapy in advanced Wilms' Turnout. Journal of Pediatric Surgery 1991;26:610 612. 6 Poster RB, Jones DB, Spirt BA. Percutaneous pediatric renal biopsy: use of the Biopty gun. Radiology 1990;176:725-727.
240
CLINICAL RADIOLOGY
7 Klose KC, Mertens R, Alzen G, Loer F, Bocking A. CT-guided percutaneous large-bore biopsies in benign and malignant pediatric lesions. Cardiovascular andlnterventional Radiology 1991;14:78 83. 8 Rosenberg HK, Sherman NH. Ultrasound guidance for interventional and intraoperative techniques in infants and children. Clinical Pediatrics 1990;29:457-463. 9 Hoffer FA, Kozakewich H, Shamberger RC. Percutaneous biopsy of thoracic lesions in children. Cardiovascular and Interventional Radiology 1990;13:32-35. 10 Towbin RB, Strife JL. Percutaneous aspiration, drainage, and biopsies in children~ Radiology 1985; 157:81-85.
11 Sabbah R, Ghandour M, Ali A, Lewall D. Tru-cut needle biopsy of abdominal tumours in children: a safe and diagnostic procedure. Cancer 1981;47:2533-2535. 12 Hughes M, Marsden MB, Palmer MK. Histologic patterns of neuroblastoma related to prognosis and clinical staging. Cancer 1974;34:1706-1711. 13 Shimada H, Chatten J, Newton WA Jr, Sachs N, Hamoudi AB, Chiba T et al. Histopathologic prognostic factors in neuroblastic tumors: definition of subtypes of ganglioneuroblastoma and an agelinked classification of neuroblastomas. Journal of the National Cancer Institute 1984;73:405-413.