Part 2 book “Paediatrics and child health” has contents: Solid tumours and histiocytosis, endocrinology, metabolic diseases, genetics, immunology, rheumatology, speech and language therapy, neonatal and general paediatric surgery, otorhinolaryngology, oral and dental surgery, orthopaedics and fractures,… and other contents.
337 Chapter Twelve Solid Tumours and Histiocytosis Jon Pritchard • Richard Grundy Antony Michalski • Mark N Gaze Gill A Levitt INTRODUCTION Cancer affects about in 600 children worldwide Leukaemia (bone marrow cancer) is the commonest form (30–35% of all cancer in childhood), followed by brain tumours (20–25%), lymphomas including Hodgkin’s disease (10%), soft tissue sarcomas, particularly rhabdomyosarcoma (8%), neuroblastoma and Wilms’ tumour (6–7%) Leukaemia and lymphoma are covered in the ‘Blood Diseases’ chapter Other rarer forms of cancer also occur (see Table 12.1) Fortunately, well over half of all children with cancer and leukaemia can now be completely cured Unlike some other diseases (e.g diabetes), patients cured of childhood cancer not need to continue treatment for life; their treatment usually stops after three to 36 months Today, around one in 1,000 young people in their twenties have already been cured of childhood cancer Table 12.1 Types of childhood cancers and cure rates Type of Cancer Acute lymphocytic leukaemia (ALL)* Brain tumour Lymphomas – Hodgkin’s disease Non-Hodgkin’s lymphomas Sarcomas of soft tissue Acute myeloid leukaemia (AML) Neuroblastoma Wilms’ tumour (nephroblastoma) Osteosarcoma Ewing’s sarcoma (PNET)*** Malignant germ cell tumour Retinoblastoma Rare tumours**** Percentage of children’s cancer 25–30% 20–25% 4% 6% 8–9% 7–8% 7–8% 6–7% 3–4% 3–4% 2–3% 3% 2–3% Current average cure rate 60–70% See** 80–90% 60–90% 60% 50–60% 50% 85% 60% 60% 80–90% 95% Variable * Chances of cure in individual children are dependent on the sub-type and stage of the cancer or leukaemia in the child and on the treatment the child receives These figures are ‘averages’ – i.e only a guide to the chance of cure for a particular patient ** There are several types of brain tumour and the average chance of cure varies with each type *** PNET = Primitive neuro-ectodermal tumour outside the central nervous system **** e.g hepatoblastoma, carcinomas, adrenal tumours Solid Tumours and Histiocytosis 338 WILMS’ TUMOUR AND OTHER RENAL TUMOURS See also ‘Urology’ chapter Wilms’ tumour (nephroblastoma) is by far the commonest type of renal tumour in childhood, but other varieties occur (Table 12.2) Around 80–90 cases of Wilms’ tumour occur in the UK each year, representing around 6–7% of all childhood cancers EPIDEMIOLOGY / AETIOLOGY With the exception of clear cell sarcoma of the kidney (CCSK), which is commoner in boys, the genders are almost equally affected No clear environmental risk factor has emerged but Wilms’ tumour is 1.5 times more common in Afro-Caribbeans than in Caucasians and least common in Asian populations Familial Wilms’ tumour (dominant inheritance) is occasionally seen but there are other, commoner Wilms’ ‘predisposition syndromes’, including: • Wiedemann-Beckwith syndrome • Denys-Drash syndrome • Perlman syndrome (very rare) • The ‘WAGR’ (Wilms’ tumour, Aniridia, abnormal Genitalia and growth Retardation) syndrome About 5% of tumours are bilateral ‘Sporadic’ Wilms’ tumours typically present in the fourth year of life, but children with bilateral disease or a predisposing syndrome usually present earlier These observations all suggest a genetic origin for Wilms’ tumour GENETICS The molecular pathology of Wilms’ tumour is complex, with the involvement of several genes in initiation and progression, as well as disruption of normal genomic imprinting on the short arm of chromosome 11(11p) WAGR patients have a heterozygous constitutional deletion of l1p, usually visible via standard lymphocyte karyotyping (12.1) To date, only one gene, WT1, has been precisely located – at 11p13 The WT1 gene is essential for kidney development Constitutional point mutations within this gene are found consistently in Denys-Drash syndrome but fewer than 10% of sporadic tumours have any detectable abnormality of l1p 12.1 Lymphocyte karyotype from a patient with WAGR syndrome.There is a readily visible deletion from the short arm of copy of chromosome 11 (arrow), designated11p- Table 12.2 Types of renal tumour in childhood Benign Mesoblastic nephroma (mesonephric hamartoma) Angiomyolipoma Cystic nephroma Haemangioma and lymphangioma Comments Commonest in small infants There are‘typical’ and ‘cellular’ subtypes which are managed differently Occurs in association with tuberous sclerosis Probably part of the Wilms’ tumour ‘spectrum’ Malignant Wilms’ tumour Clear cell sarcoma (CCSK) Rhabdoid tumour (RTK) Carcinoma Neuroblastoma Non-Hodgkin lymphoma (NHL) Comments Variable histology (see text) Can metastasise to bone and/or brain Associated with PNET of brain May be familial Can be ‘intra-renal’ Usually bilateral, diffuse involvement Wilms’ tumour and other renal tumours PRESENTATION Most Wilms’ tumours are discovered ‘incidentally’ or because parents or grandparents notice abdominal enlargement (12.2 and 12.3) They are often very large at diagnosis Pain is uncommon and usually attributed to intra-tumoral bleeding, whilst haematuria occurs in only 10–15% Presentation with tumour rupture, varicoele, hypertension or symptoms of metastatic spread is rare INVESTIGATIONS Imaging: Initial screening of abdominal masses is with ultrasound, to exclude cystic lesions, which may show the blood ‘lakes’ characteristic of intra-tumoral bleeding in Wilms’ tumour but not other types of renal tumour CT and MRI scanning are equally effective in demonstrating the renal origin of the primary tumours, the anatomy of the ‘opposite’ kidney – to exclude bilateral disease (12.4) – and determining whether or not the IVC is involved (12.5) These days, because of the considerable radiation dose from CT, MRI is preferred Children with Wilms’ tumours should have chest x-rays and chest computerized tomography (CT) to investigate for lung metastases Those with CCSK and RTK should have, in addition, an istotope bone scan and a CT or MRI brain scan, if clinically indicated Other investigations: Some patients have a low haemoglobin because of intra-tumoral bleeding The partial thromboplastin time (PTT) may be prolonged because some Wilms’ tumours make an anti-von Willebrand factor If proteinuria is present, Denys-Drash syndrome should be suspected Constitutional karyotype studies 12.4 CT scan of abdomen showing huge L Wilms’ tumour and a normal R kidney IVC (arrow) 12.2 Two-year old girl on day of diagnosis of Lsided Wilms’.The tumour weighed kg but was histopathologically stage I and of ‘favourable’ histology (FH) 12.3 The same girl, 6.5 years later, cured by surgery and vincristine chemotherapy only Apart from nephrectomy, there are no discernible ‘late effects’ 12.5 CT scan showing renal vein and IVC involvement (arrow) by direct tumour extension Pre-operative chemotherapy is indicated 339 Solid Tumours and Histiocytosis 340 should be carried out if the patient is dysmorphic Histopathology: Malignant tumours are stratified into those with a relatively favourable prognosis: FH (‘favourable histology’) and those with a lesser likelihood of cure – UH (‘unfavourable histology’) 12.6 shows a standard ‘triphasic’, FH Wilms’ tumour and 12.7 shows an area of ‘anaplasia’ in a UH tumour Clear cell sarcoma of the kidney (CCSK) and rhabdoid tumour of the kidney (RTK), previously categorized as UH, are not Wilms’ tumours at all Nephroblastomatosis, a curious tumour-like condition, is associated with Wilms’ and is often assumed to be a precursor lesion Staging: Two staging systems are in common use The National Wilms’ Tumour System (NWTS) is most appropriate when patients have surgery first, but the International Society of Paediatric Oncology (SIOP) system is preferred for patients having preoperative chemotherapy The NWTS system is shown in Table 12.3 PROGNOSIS Survival for FH patients is: Stage I, >95%; Stage II, >90%; Stage III, 80–85%; Stage IV, 60–80% (overall FH survival is 85%) For UH patients (all stages) survival is: anaplastic tumours, 60%; CCSK, 80% (doxorubicin is the crucial drug for CCSK) and RTK, 20% Cure is possible for up to half of relapsing patients, especially those who have received only one or two chemotherapy drugs and no radiotherapy ‘first time around’ LATE EFFECTS Rather than ‘cure at any cost’, the objective in treating Wilms’ tumour is ‘cure at least cost’ Therapists try to avoid some of the ‘late effects’ by omitting that treatment whenever it can be shown, by clinical trial, to be unnecessary Aside from the usual reasons for referral to a tertiary paediatric oncology centre, avoidance of unnecessary therapy is crucial for these patients COURTESY OF PROF TONY RISDON COURTESY OF PROF TONY RISDON TREATMENT There has been a divergence of opinion between Europe and the USA as to the merits of preoperative chemotherapy versus immediate nephrectomy In Britain, the UKWT3 trial randomized between the two: no difference in survival was evident but less operative morbidity in the preoperative group was reported Importantly, there was ‘stage migration’, with more children having lower-stage disease and less treatment Treatment within Europe, including Britain, uses 4–6 weeks of preoperative chemotherapy with vincristine and actinomycin D Postoperative treatment depends on the stage and histological sub-type 12.6 ‘Typical’ triphasic Wilms’ tumour (‘FH’) showing blastema (single arrow), epithelial structures (double arrow) and stroma 12.7 ‘UH’ tumour because of focal anaplasia Atypical nuclei are arrowed Table 12.3 National Wilms’ tumour staging system Stage I Stage II Stage III Stage IV Bilateral Single tumour confined to kidney and completely excised, pathologically Single tumour invading through pseudo-capsule but completely excised, pathologically: tumour rupture into flank only Single tumour either invading into adjacent tissues and incompletely excised or tumour inoperable, usually because of IVC invasion (Figure 12.5) any abdominal lymph nodes positive: tumour rupture with diffuse peritoneal contamination Metastatic disease, excepting abdominal lymph nodes Primary tumours in both kidneys Liver tumours 341 LIVER TUMOURS In sharp contrast to adults, primary liver tumours in children are more common than secondary tumours Both benign and malignant types occur (Table 12.4) Overall, they represent 1–2% of all children’s tumours and about 1% of all children’s cancers Males are more commonly affected than females AETIOLOGY Hepatoblastoma is associated with familial adenomatous polyposis (FAP) and with Beckwith-Wiedemann syndrome Hepatocellular carcinoma often arises in a liver previously damaged by hepatitis B virus, and is therefore commoner in epidemic areas (e.g., Taiwan), or by metabolic liver disease, especially glycogen storage disease (GSD) type I and tyrosinosis PRESENTATION Liver tumours usually present with upper abdominal distension (12.8) Pain is unusual and jaundice only occurs in some children with biliary rhabdomyosarcoma Besides increased levels of alpha-fetoprotein (α-FP), which must be interpreted according to the patient’s age, thrombocytosis (due to release of a thrombopoietin) is characteristic of hepatoblastoma and hepatocellular carcinoma Rarely, hepatoblastomas secrete ACTH or sex hormones and the 12.8 Distended upper abdomen in a child with hepatoblastoma Note that there is no jaundice corresponding endocrine syndrome develops Imaging: The lungs are by far the most frequent site for metastatic hepatoblastoma and hepatocellular carcinoma, so chest x-ray and computerized tomographic (CT) scan of the lungs are mandatory Magnetic resonance imaging (MRI) is probably better than CT at displaying the anatomy and focality of the primary tumour, and vividly reflects treatment response (12.9) Table 12.4 Types of liver tumour and relationship to level* of serum α-fetoprotein (α-FP) at diagnosis Undetectable Slight elevation Very high Benign Adenoma 50% 50% – Haemangioma Haemangioendothelioma Mesenchymal hamartoma All All 50% – – 50% – – – Hepatoblastoma Hepatocellular carcinoma** Sarcoma 80% For hepatocellular carcinoma, prognosis is still relatively poor because tumours are often multifocal and/or metastatic at diagnosis; however, unifocal tumours are curable in at least 50% of cases Liver transplant is a realistic option for ‘unresectable’ tumours responding to chemotherapy, without evidence of extra-hepatic spread α-FP 107 106 105 104 103 102 101 100 COURTESY OF PROFESSOR JAMES LEONARD 12.9 MRI showing large unifocal hepatoblastoma (arrows) prior to and after three months of ‘PLADO’ chemotherapy 12.10 CT scan showing multiple adenomas in the liver of a boy with GSD type 1.With adequate dietary control, tumour growth usually slows down and tumours may regress, as occurred in this case 10 Weeks 15 20 12.11 Serum α-FP response to courses of ‘PLADO’ chemotherapy (solid arrows – see text) in a 1.5-year-old child with hepatoblastoma.The t1/2 is 4–5 days, indicating a major tumour response Complete surgical resection was achieved (open lozenge).The MRI scans of this patient, who is a long-term survivor, are shown in 12.9 Histiocytosis HISTIOCYTOSIS There are two main types of histiocytes, both derived from pluri-potential stem cells of the bone marrow The principal function of one type is antigen-processing, chiefly by phagocytosis: members of the family of cells include the circulating blood monocyte, the pulmonary alveolar macrophage, the hepatic Kupffer cell and the so-called ‘microglia’ of the central nervous system (CNS) The other type of histiocyte is chiefly concerned with antigen presentation and the Langerhans cell, which forms a ‘network’ at the dermo–epidermal junction, over the entire body surface, is the most notable member of this cell family Pathologically and clinically, distinct types of histiocytosis arise from these two cell types Haemophagocytic lymphohistiocytosis (HLH) and Rosai Dorfman disease seem to be disorders of phagocytes (Type I histiocytosis) while Langerhans cell histiocytosis (LCH) is a disease of Langerhans cells (Type II histiocytosis) Although sometimes progressive and (especially in the case of HLH) fatal, none of these disorders is currently regarded as ‘malignant’ True malignant histiocytosis (Type III) is exceptionally rare in children and will not be discussed here 12.12 High resolution CT scan of skull, showing soft tissue mass in middle ear with adjacent destruction of the petrous temporal bone and invasion of the structures of the middle and inner ear The patient, a five-year-old girl, presented with an aural polyp and deafness Only the skeleton was involved in this patient (‘single-system disease’) 343 LANGERHANS CELL HISTIOCYTOSIS Aetiology/epidemiology Langerhans cell histiocytosis (LCH) is caused by a clonal proliferation of pathological Langerhans cells (LCH cells) which invade a range of organs in which their normal counterparts are never found and attract several types of ‘inflammatory’ cells, forming an infiltrate LCH is commoner in boys than in girls, and also occurs in adults Inheritance The cause of LCH has not been identified Epidemiological studies reveal a uniform racial and geographical distribution, with no ‘clustering’ of cases in time or space and, to date, no specific cytogenetic or molecular lesion has been identified in LCH cells On the other hand, familial clustering, including identical twins, have been reported Clinical presentation Histiocytosis can affect many organ systems Lytic bone lesions often heal slowly but completely, although deformity and disability can occur The skull bones are commonly affected (12.12, 12.13) resulting in sequelae including deafness and proptosis Skin involvement can resemble seborrhoeic dematitis involving the 12.13 Skull radiograph showing ‘punched-out’ lytic deposits in the skull table of a five-year old boy with ‘multi-system’ LCH.The inset shows the corresponding radionuclide scan after injection of an 111In radiolabelled mouse anti-CDla antibody.There is increased uptake in the skull lesions and in Waldeyer’s ring 344 Solid Tumours and Histiocytosis flexural creases (12.14) and purpura can appear if platelets are low (12.15) Restrictive lung defects with cysts and bullae formation may result in pneumothoraces; pulmonary fibrosis is a chronic sequela (12.16, 12.17) Liver disease may progress to biliary cirrhosis Lymph node and splenic enlargement can be massive and lymph nodes may erode to create sinuses Small and large gut involvement is often underdiagnosed Selective invasion of the pituitary/hypothalamus region (12.18) causes diabetes insipidus and growth hormone deficiency in 40% and 10% of cases respectively Other CNS complications include cerebellar white matter involvement, resulting in ataxia (12.19) and cerebral mass lesions 12.14 Seborrhoea-like rash involving the scalp and external ear of a two-year-old girl with multi-system LCH.The condition had previously been diagnosed as ‘seborrhoeic eczema’; the cotton-wool plug provides the diagnostic clue! Eighteen years later, she is alive and disease-free Classification LCH is classified according to whether one (‘single-system disease’) or more (‘multi-system disease’) organs is/are affected The commonest form of LCH (around 50%) is single-system bony disease, with one or more lytic lesions in almost any bone These lesions are also known as ‘eosinophilic granuloma’ Skin involvement (12.14) is also common, in a characteristic distribution (see also ‘Dermatology’ chapter) Some 5–10% of patients have severe multisystem disease, with organ failure (‘LettererSiwe disease’) and the remaining 40–45% suffer disease with intermediate severity Diabetes insipidus, in up to 40% of patients, is the commonest chronic sequel of LCH Diagnosis The picture is similar in all forms of LCH The infiltrating lesion is heterogeneous but LCH cells, characterized by CDla positivity are present in every case, together with ‘ordinary’ histiocytes, neutrophils, eosinophils, giant cells and T lymphocytes In chronic disease, CDlapositive cells disappear and fibrosis or, in the brain, gliosis are the dominant features Full blood count, liver function tests with plasma albumin and coagulation studies, chest x-ray, radiographic skeletal survey (preferred to isotope bone scanning) and early morning urine osmolarity are needed in each patient This initial screening may indicate the need for other investigations including bone marrow, liver or gut biopsy, CT scan of lungs and/or respiratory function tests, dental or aural radiographs, MRI scan of pituitary and brain Using these results, patients are categorized into those with single-system disease and those with multi-system LCH with/without organ dysfunction 12.15 Widespread, confluent central truncal rash and petechiae in an infant with multisystem LCH and thrombocytopenia due to ‘haemopoietic failure’ despite treatment.This 14-month-old boy died six months later, from progressive LCH Histiocytosis 12.16 LCH pulmonary disease X-ray showing a four-year old boy at diagnosis, with interstitial infiltrate and bilateral pneumothorax The same patient aged 18 years had a much-reduced chest volume secondary to lung fibrosis with secondary cyst formation 345 12.18 Pituitary stalk thickening (increased from to 2–3 mm) and absence of the posterior pituitary ‘bright signal’ in this Tlweighted MRI scan of a two-year-old boy with proven diabetes insipidus (DI) but normal growth.The DI was well-controlled with oral DDAVP tablets Anterior pituitary function was normal a b 12.19 MRI scans (T2 weighted) of 10-year-old patient with multi-system LCH since birth and cerebellar ataxia, evolving over the previous four years.The symmetrical changes in the white matter of both cerebellar hemispheres (a) are characteristic of ‘burnt-out’ LCH Scan in a normal 9–10 year old (b) 12.17 A high magnification view of the lung of another patient, who was a smoker, showing intense interstitial shadowing; biopsy confirmed ‘active’ LCH 346 Solid Tumours and Histiocytosis Treatment/prognosis Patients with single-system disease usually have an excellent prognosis Systemic treatment is rarely needed and spontaneous regression is common Helpful ‘local’ therapies include topical anti-inflammatory lotions and tar-based shampoos, intra-lesional steroids and/or oral indomethacin for bone pain and surgical debridement of aural/oral lesions Patients with multi-system LCH require systemic therapy with steroids and cytotoxic drugs; however, ‘local’ therapies can be a helpful ‘adjuvant’ to management Diabetes insipidus is managed by replacement DDAVP and GH deficiency by GH supplementation Hepatic failure may be treated with transplantation Adverse prognostic factors for multi-system LCH include age