[Differential diagnosis of retinoblastoma: a retrospective study of 486 cases]

OBJECTIVES

Detail the most frequent problems encountered in the differential diagnosis of retinoblastoma.

PATIENTS

and method: We conducted a retrospective study on the children referred to the Curie Institute for suspicion of retinoblastoma between 2000 and 2006. Diagnosis was made by fundus examination using the indirect ophthalmoscope, ultrasonography, and MRI.

RESULTS

Of the 486 children seen during this period, 408 had unilateral or bilateral retinoblastoma and 78 (16%) had another lesion: Coats disease (20 children, 25%), congenital malformations (23 children, 30%; coloboma, PHPV, microphthalmia, isolated or associated with retinal dysplasia), other tumors (10 children, 13%; astrocytomas and medulloepithelioma), combined hamartomas (six children, 8%), inflammatory diseases (six children, 8%) (Toxocara canis, cat scratch eye disease, or toxoplasmosis), and other diseases (13 children, 16%; corneal opacities, congenital cataract, or retinal detachment).

DISCUSSION

Compared to previous series, this study shows the proportion of erroneous diagnosis has lowered (16%) compared to earlier studies by Balmer (1986; 30%), and Shields (1991; 42%). No cases of retinopathy of prematurity were seen in our series, demonstrating that screening is good or of a lower frequency in France. The frequency of PHPV has dropped. Coats disease remains a frequent and sometimes difficult diagnosis to make, particularly in advanced stages of the disease.

Imaging of sacral tumours

All components of the sacrum (bone, cartilage, bone marrow, meninges, nerves, notochord remnants, etc.) can give rise to benign or malignant tumours. Bone metastases and intraosseous sites of haematological malignancies, lymphoma and multiple myeloma are the most frequent aetiologies, while primary bone tumours and meningeal or nerve tumours are less common. Some histological types have a predilection for the sacrum, especially chordoma and giant cell tumour. Clinical signs are usually minor, and sacral tumours are often discovered in the context of nerve root or pelvic organ compression. The roles of conventional radiology, CT and MRI are described and compared with the histological features of the main tumours. The impact of imaging on treatment decisions and follow-up is also reviewed.

PET/CT imaging: what radiologists need to know

Positron emission tomography (PET)/computed tomography (CT) imaging is frequently requested in Oncology. Radiologists and nuclear medicine physicians are often asked to perform a panel of imaging examinations as part of the initial staging or follow-up of cancer patients. Medical imaging must therefore integrate polyvalent skills enabling imaging specialists to understand and interpret all types of images. In this context, PET imaging combined with non-enhanced CT, and diagnostic quality contrast-enhanced CT scan and optimisation of CT settings, is part of this multidisciplinary approach requiring the specific skills of a radiologist and a nuclear medicine physician. This approach must therefore be conducted in both directions: radiologists and nuclear medicine physicians should both know how to correlate PET and CT images, while preserving the specificities of each discipline. Radiologists need to be aware of several aspects of PET imaging: PET technology, the examination procedure and injection of iodinated contrast agent for high quality diagnostic CT, ideally followed by double interpretation of CT images, PET images and fused images. Radiologists should be familiar with PET imaging, as this procedure may be associated with several pitfalls and artefacts that need interpretation by a trained specialist. The authors analyse the examination technique of PET combined with non-enhanced and/or contrast-enhanced CT and the proposals for optimal interpretation of normal or pathological PET/CT fusion images.

Chromosomal CGH identifies patients with a higher risk of relapse in neuroblastoma without MYCN amplification

Whereas neuroblastoma (NB) with MYCN amplification presents a poor prognosis, no single marker allows to reliably predict outcome in tumours without MYCN amplification. We report here an extensive analysis of 147 NB samples at diagnosis, without MYCN amplification, by chromosomal comparative genomic hybridisation (CGH), providing a comprehensive overview of their genomic imbalances. Comparative genomic hybridisation profiles showed gains or losses of entire chromosomes (type 1) in 71 cases, whereas partial chromosome gains or losses (type 2), including gain involving 17q were observed in 68 cases. Atypical profiles were present in eight cases. A type 1 profile was observed more frequently in localised disease (P<0.0001), and in patients of less than 12 months at diagnosis (P<0.0001). A type 2 genomic profile was associated with a higher risk of relapse in the overall population (log-rank test; P<0.0001), but also in the subgroup of patients with localised disease (log-rank test, P=0.007). In multivariate analysis, the genomic profile was the strongest independent prognostic factor. In conclusion, the genomic profile is of prognostic impact in patients without MYCN amplification, making it a help in the management of low-stage NB. Further studies using higher-resolution CGH are needed to better characterise atypical genomic alterations.

Improving the interpretation of bone marrow imaging in cancer patients

Magnetic resonance imaging (MRI) is the best technique for bone marrow imaging. The MRI signal of bone marrow depends on the quantity of fat it contains and on its cellularity. Evaluation of marrow of patients treated for cancer is complicated by age and osseous site related changes in the distribution of normal haematopoietic (red) and fatty (yellow) marrow and by the changes induced by treatments: decrease in pathological cellularity, increase in fat proportion, conversion of red marrow to fatty marrow or, conversely, reconversion of fatty marrow in normal haematopoietic red marrow. The treatments used in oncology modify pathological marrow but also normal marrow and may sometimes lead to complications. These modifications may be focal or diffuse, homogeneous or patchy and symmetrical or asymmetric. The knowledge of bone marrow physiological status and post-therapeutic patterns is important for the interpretation of marrow disorders and effects of therapy and to avoid false-positive diagnosis of marrow metastases and tumour progression. The aim of this paper is to recall the MRI patterns of normal bone marrow and normal variations and to show the effects of treatments on bone tissue and normal bone marrow and treatment-related modifications on pathological marrow.

[Rhabdomyosarcoma of the genitourinary sinus in children]

Genitourinary rhabdomyosarcoma (RMS) accounts for approximately 25% of all rhabdomyosarcomas. Management of RMS at this site has changed during the last 5 consecutive Intergroup Rhabdomyosarcoma (IRS) trials, with increasing emphasis of bladder and vaginal conservation. As more effective treatment regimens has improved survival, surgical approaches have evolved to less aggressive management of the primary tumour to improve conservation. Various combinations of chemotherapy, irradiation and surgery have resulted in a decreased late sequelae in the group of patients with sarcoma arising in the genitourinary tract.

Hypertension in childhood cancer: a frequent complication of certain tumor sites

The clinical features and management of severe hypertension (HT) (blood pressure > 99th percentile + 5 mm Hg) have been rarely described in pediatric oncology.

OBJECTIVES

Retrospective descriptive study of the case files of 31 patients followed in the Institut Curie Department of Pediatric Oncology between 1999 and 2004 and presenting severe HT at the time of diagnosis of their tumor.

RESULTS

The median age was 2 years 1 month (range: 3 mo to 6 y 8 mo). Median blood pressure was 99th percentile + 30 mm Hg (range: 99th percentile + 7 mm Hg to 99th percentile + 62 mm Hg). The tumors presented by these children were: Wilms tumor (n=17, ie, 20% of all Wilms tumors treated during this period), neuroblastoma (n=12, ie, 10% of all neuroblastomas treated during this period) or other tumors (n=2). HT was asymptomatic in all children. Initial management consisted of etiologic treatment by primary chemotherapy and/or surgical resection of the tumor, associated with antihypertensive therapy, initially administered by intravenous injection for 12 children (nicardipine, labetalol) and then orally in all children (calcium channel blockers, n=23; angiotensin-converting enzyme inhibitor, n=16; beta-blockers, n=4; alpha/beta-blockers, n=2; diuretics, n=1). Dual therapy was necessary in 7 cases and triple therapy was necessary in 1 case. The median duration of antihypertensive therapy was 40 days (range: 9 to 195). No child developed a serious complication of HT.

CONCLUSIONS

Initial HT is a frequent complication of Wilms tumor and neuroblastoma and affects young children (< 2.5 y). It is often severe, asymptomatic, but needs specific treatment and resolves after treatment of the tumor.

Portal vein thrombosis during antineoplastic chemotherapy in children: Report of five cases and review of the literature

We report five paediatric cases of portal vein thrombosis (PVT) occurring during chemotherapy, observed in two institutions over an 8-year time period. These children aged 2.5-15 years were treated for Burkitt's lymphoma, Ewing's tumour, small cell bone tumour or medulloblastoma. PVT was diagnosed on colour Doppler ultrasonography (US). In four patients, thrombosis occurred 2-45 days after severe hepatic veno-occlusive disease (HVOD) secondary to intensive chemotherapy containing busulfan. In one case, PVT occurred in the absence of HVOD in a patient with pre-existing periportal lymphomatous infiltration. Four patients experienced persistent portal hypertension, which resulted in death in one. PVT during chemotherapy in children is a rare event and appears to be closely related to intensive chemotherapy containing busulfan and to be associated with HVOD.

Laparoscopic adrenal surgery for neuroblastomas in children

PURPOSE

The role of laparoscopy in children with neuroblastomas has not been fully defined. The laparoscopic approach to the adrenal gland is already largely used in adults and a few cases have been reported in children. We report the experience of a single surgical team center with laparoscopic adrenal surgery for neuroblastomas in children.

MATERIALS AND METHODS

Between September 2000 and October 2002 laparoscopic adrenalectomy for neuroblastoma was performed in 9 patients (6 girls and 3 boys) with a mean age of 38 months (range 2 months to 9 years). Two tumors were detected prenatally and 7 postnatally. Preoperative diagnosis was neuroblastoma stage I in 4 cases and stage IV in 3 cases, and nondetermined suprarenal calcified masses in 2 cases. A 4 or 5-trocar transperitoneal approach was used in all cases. The adrenal tumors were completely excised, placed into a plastic bag and removed through the umbilical trocar site.

RESULTS

All of the adrenal tumors were well encapsulated and completely excised. One of the 9 procedures was converted to open surgery because of adhesions to renal vessels. In 1 case a second hepatic localization was removed simultaneously, and in 3 cases 1 or more lymph nodes were resected. Average operative time was 85 minutes (range 45 to 170). There were no deaths. There were no postoperative complications, except 1 port site infection that was treated locally. Blood transfusion was not required. Average hospital stay was 4.5 days (range 2 to 10). Histological analysis of the 9 specimens (maximum length 6 cm) confirmed the diagnosis of neuroblastoma. N-myc status was studied in 8 of the 9 resected neuroblastomas and was amplified in 2 cases (both stage IV with preoperative biopsy). Average postoperative followup was 15 months (range 1 to 25). There was no local recurrence or metastasis, except in the case that required conversion to open surgery (local recurrence 7 months later).

CONCLUSIONS

Laparoscopic adrenalectomy for neuroblastoma is safe and feasible in children, with good results. Experience with advanced laparoscopic surgery is required to achieve this result in optimal oncological conditions. Our short-term results must be reevaluated at long term, and further studies are needed to compare laparoscopy to open surgical techniques.

[Central neurological manifestations during chemotherapy in children]

The central neurotoxicity of cytotoxic drugs depends on their ability to cross the blood-brain barrier (BBB). The drugs with the highest neurotoxicity are therefore those that cross the BBB most easily: alkylating agents (metabolites of cyclophosphamide and ifosfamide, thiotepa and high-dose melphalan), busulfan, platinum derivatives, aracytine and methotrexate. Apart from aracytine-induced cerebellar toxicity, the clinical signs suggestive of chemotherapy neurotoxicity are relatively nonspecific: altered level of consciousness, seizures, behavioural disorders and motor deficits. Nevertheless, a good knowledge of the various neurological syndromes likely to occur can allow them to be attributed to a drug-induced cause. However, as patients may be receiving several potentially neurotoxic treatments (chemotherapy, concomitant drugs, neurosurgery, radiotherapy), it is difficult to formally confirm the responsibility of the drug, which should only be considered after confirming the absence of radiological and metabolic abnormalities. A specific antagonist treatment can be administered in rare cases (ifosfamide-induced encephalopathy).

Neoadjuvant chemotherapy for extensive unilateral retinoblastoma

AIM

The role of neoadjuvant chemotherapy was studied when first line enucleation cannot be safely performed in unilateral extensive retinoblastoma (major buphthalmia or radiologically detectable optic nerve involvement).

METHODS

Six patients, referred for unilateral retinoblastoma, presented with major buphthalmia (two) or optic nerve invasion (four): they were treated by neoadjuvant chemotherapy using etoposide and carboplatin.

RESULTS

Good tumour response was observed in the two patients with buphthalmia and in three of four cases with optic nerve involvement. Meningeal progressive disease was observed in the last patient. The five patients without disease progression were then operated on: anterior enucleation in the patients with buphthalmia and enucleation via a double neurosurgical and ophthalmological approach with prechiasmatic optic nerve section in the other three cases. Postoperative chemotherapy was performed in these five patients. Local radiotherapy to the chiasmatic region and posterior part of the optic canal was necessary in only one patient. The non-operated patient died with disease progression 6 months after the diagnosis. The other five patients are alive with a follow up of 12, 15, 21, 36, and 40 months after stopping treatment.

CONCLUSION

Neoadjuvant chemotherapy can be useful in extensive unilateral retinoblastoma with buphthalmia and/or radiological optic nerve invasion at diagnosis.

Outcome of suprarenal localized masses diagnosed during the perinatal period: a retrospective multicenter study

BACKGROUND

The growing use of abdominal ultrasonography during pregnancy and in the postnatal period is leading to the discovery of an increasing number of suprarenal masses. The optimal diagnosis and treatment of these masses has not yet been determined.

METHODS

The authors reviewed the files of patients with suprarenal masses detected prenatally or during the first 3 months of life, between 1986 and 1999, in the pediatric surgery and oncology departments of Paris hospitals.

RESULTS

Thirty masses were detected prenatally and 23 postnatally. In the latter group of patients, the diagnosis was based on ultrasound in 8 cases and on the palpation of a mass in 15 cases, 13 of which were neuroblastoma. At birth, the masses were cystic in 19 cases, solid in 17, and mixed in 13. Sensitivities of methyliodobenzylguanidine and urinary catecholamine assay were 70% and 52% respectively. Surgery was performed in 38 cases with a median age of 42 days. Histologic analysis showed 31 neuroblastomas, 1 adrenal hemorrhage, 2 necrotic masses, 1 bronchogenic cyst, and 3 sequestrations. All the patients were alive and disease free, at a follow-up ranging from 3 months to 13 years.

CONCLUSIONS

In this series, 58% of the suprarenal masses diagnosed perinatally were localized neuroblastoma with a favorable outcome. All other cases either regressed spontaneously or turned out to be benign lesion. Thus, the management of these masses must strike a compromise between aggressive treatment and a wait-and-see attitude. This requires appropriate initial assessment and a close follow-up in a specialized center.

[Ultrasound in pediatric urology]

GENERAL OBJECTIVE: To review technical considerations, indications, findings and limitations of ultrasound and Doppler in pediatric urology.

EDUCATIONAL OBJECTIVES

This course aims to help the reader improve his/her own technical skills and knowledge of ultrasound findings as well as their significance in pediatric urology. The most common causes of misinterpretation and limitations are reviewed. The scope of the article is limited to common diseases: infection, urinary tract malformation, trauma and tumor. Because ultrasound cannot be separated from other imaging modalities, the indications for each of these imaging modalities are provided in relevant sections.

[Current strategy for the imaging of neuroblastoma]

Advances in the management of neuroblastoma lead radiologists and nuclear medicine specialists to optimize their procedures in order to propose a rational use of their techniques, adjusted to the various clinical presentations and to therapeutic management. The aim of this paper is to assess the imaging procedures for the diagnosis and follow-up of neuroblastoma in children according to current therapeutic European protocols. An imaging strategy at diagnosis is first proposed: optimal assessment of local extension of the primary tumour is made with MRI, or spiral-CT when MRI is not available, for all locations except for abdominal tumours for which CT remains the best imaging modality. Metastatic extension is assessed with mIBG scan and liver sonography. Indications for bone metastasis evaluation with either radiological or radionuclide techniques are detailed. Imaging follow-up during treatment for metastatic or unresectable tumours is described. A check-list of radiological main points to be evaluated before surgery is proposed for localized neuroblastoma. The imaging strategy for the diagnosis of "occult" neuroblastoma is considered. Finally, we explain the management of neuroblastoma detected during the prenatal or neonatal period.