paediatric abdominal masses

Click here to load reader

Post on 30-May-2017

215 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

Paediatric Abdominal Masses

Paediatric Abdominal MassesDr.Aftab Qadir

1.Renal Masses2.Adrenal 3.Hepatobiliary 4.Pancreatic 5.Spenic 6.Gastrointestinal 7.Pelvic

Imaging plays an important role in the diagnosis and management. Plain radiographs provide clues to the location of the mass,organomegaly and the presence of calcifications. Ultrasound is generally the most valuable procedure for the initial evaluation. Ultrasound differentiates cystic from solid masses, indicates the organ of origin, and suggests the diagnosis, also about the vascular compromise and intraluminal thrombosis.

CT or MR needed when the mass is large, poorly defined, for staging or when obscured by bowel gas.Radionuclide for specific applications

Neuroblastoma is mIBG avid 3

Renal MassesCongenital Pevicalyceal dilatationInfectionNeoplasmVascularMulticystic Dysplastic kidneyAbscessMalignant: Wilms tumourRenal vein thrombosisPUJ obstructionFocal nephritisBenignHaematomaCystic renal diseaseXanthogranulomatous pyelonephritis

Benign renal massesMesoblastic nephromaMultilocular cystic nephromaAngiomyolipoma

4

Wilms tumourIt arises from the primitive metanephric epithelium Bilateral synchrous tumours occur in 5-10%.Nephroblastomatosis as precursorIncreased incidence sporadic aniridia,hemihypertrophy,Beckwith-wiedemann syndorme,Drash syndrome,Horseshoe kidney,Family history.

NephroblastomatosisSmall islands of primitive metanephric blastema, which are precursor of Wilms tumor, commonly exist in the kidneys of the normal newborn infant. These primitive cells usually spontaneously regress by 4 months of age. A diffuse and proliferative form of persistent renal blastoma is referred to as nephroblastomatosis. The abnormal tissue can form as multiple discrete nodules within the renal parenchyma or may completely replace the renal cortex. -Nephroblastomatosis appears on CT or IV pyelogram as bilateral lobulated and enlarged kidneys with marked compression, stretching, and distortion of the pelvicaliceal structures On US, the kidneys are enlarged, lobular, andechogenic, or enlarged with diffuse hypoechoic thickening of the cortex. In such cases, Wilms tumor should be suspected. Nephrogenic rests are more likely to appear cortical, tend to be homogeneous, and are of low echogenicity on US, low attenuation on CT, and low signal intensity on T1WIs . Small, focal nephrogenic rests smaller than 1 cm are difficult to visualize by US and are better evaluated with contrast-enhanced CT or T1WI

5

PresentationMostly present as asymptomatic massAbdominal painHaematuriaFeverHypertension

ImagingOn ultrasound Wilms tumor characteristically is a well-defined, predominantly solid mass Appears as echogenic, heterogeneous with cystic areas. Wilms tumor has a propensity to extend into the renal vein, inferior vena cava, and right atriumOn CT Wilms tumours are heterogeneous soft-tissue density masses, rarely calcifications and enhancement is patchy.On MRI, tumor tends to have decreased signal on T1 and increased on T2The lung is commonest site for metastases.

7

Sagittal image of the right kidney A rounded solid appearing mass is seen in the interpolar region of the right kidney. The mass shows no obvious calcifications.8

Sagittal image of the right kidney The right kidney appears enlarged and lobulated. The complex right renal mass is appreciated again in this image. The mass exhibits a few scattered areas that are hypoechoic9

Contrast enhanced axial CT scan The right renal mass is again identified in this image. The mass is seen to occupy a large portion of the kidney and invades the right renal hilum; however it does not cross the midline.10

Wilm's Tumor. Conventional radiograph of abdomen shows a large right upper mass displacingbowel loops into the pelvis and accross the midline (blue arrows). Coronal and sagittal reformatted CTdemonstrate a large, heterogeneous mass arising from the right kidney (white arrows). A smallsliver of functioning right kidney is seen to enhance (yellow arrow).11

Tumor stagingDetermined by imaging and surgical findings.Stage 1:Encapsulated tumor completely excised.Stage 2:Extends beyond the kidney, completely excisedStage 3:Residual tumor confined to abdomen and nodesStage 4:Haemetogenous metastasisStage 5:Bilateral tumours at diagnosis

5 year survival exceeds 90% in those with early stage and favorable histology.

A tumor biopsy is not typically performed due to the chance of upstaging the cancer and seeding the abdomen with malignant cells.

TreatmentThe main types of treatment that can be used for Wilm's tumor are:SurgeryChemotherapyRadiation therapy

Nephrectomy followed by chemotherapyPostoperative radiation therapy for stage II and IV lesions

Renal cell carcinoma is very rare in young children but sometimes occurs in older children and adolescentsThe imaging characteristics of renal cell carcinoma are indistinguishable from those of Wilm's tumor.

Adrenal MassesAdrenal Hemorrhage Commonest cause of adrenal massMay be unilateral or bilateral

Predisposing factors include large babies, obstetric trauma, neonatal sepsis, and hypoxia

Ultrasound: demonstrate an avascular heterogeneous adrenal mass that has becomes cystic and smaller over the following weeks as clot retractions occur.Serial ultrasound to document the typical course of cystic changes and resolution, usually evolves from hyper echoic to iso-echoic to hypo-echoic.

Adrenal HemorrhageThe infants may present with an abdominal mass, jaundice, hypotension, or anemia, but small hemorrhages may go unnoticed. Hemorrhage occurs more frequently on the right and is occasionally bilateral. Older children develop adrenal hemorrhage as a result of accidental trauma, child abuse, meningococcemia, or anticoagulant therapyHemorrhage enlarges the gland and causes loss of the V shape. Initially, the hematoma resembles a solid, echogenic mass . As the hemorrhage resolves, it becomes increasingly hypoechoic, starting in the central region and progressing peripherally . 15

hypo-echoic hematoma in the right adrenalAdrenal hemorrhage longitudinalAdrenal hemorrhage without vascularity longitudinal

17

NeuroblastomaMalignant tumor of neural crest cellsCommonest extracranial solid malignant tumorApproximately 70% originate in the abdomen of which 2/3rd arise in adrenal,20% in the chest and 10% in the head and neck

The etiology of neuroblastoma is not well understood. The great majority of cases are sporadic and non-familial.detect neuroblastoma is the mIBG scan (meta-iodobenzylguanidine), which is taken up by 90 to 95% of all neuroblastomas, often termed "mIBG-avid18

May present as palpable abdominal mass or non specific symptoms50 to 60% of all neuroblastoma cases present with metastases

Radiological imagingUltrasound demonstrates a hyperechoic mass in the adrenal or central retroperitonuem often with flecks of calcification. Doppler for flow in encased vessels

CT confirms the calcification with low attenuation mass.

The most characteristic imaging feature is the encasement of adjacent vessels

99m Tc MDP scintigraphy is useful for detection of bone metastasis.mIBG scan

Tc-99m MDP (Bone Scan)MIBG scintiscan20

A well-defined, rounded, mildly lobulated, hypoechoic mass that is separate from the liver is noted in the right upper quadrant. The mass has areas of calcification and appears to displace the kidney downwards and medially.21

StagingInvolve the radiological, surgical and bone marrow aspirate:Stage 1:confined to organ of originStage 2: extending beyond the organ of origin, unilateral nodal diseaseStage 3:extending across the midline, bilateral nodal diseaseStage 4: distant metastasesStage 4s: age15cm at presentation

SerologyCA-125 levels - elevated in most ovarian malignancies (~ 80% in general)

AFP levels - elevated particularly with immature ovarian teratomas (~ 50% of cases) and ovarian yolk sac tumours

ImagingOn ultrasound solid and cystic component can be demonstrated CT can demonstrate the solid-cystic mass with fat and calcific componentsIt is not possible to determine whether a mass is benign or malignant unless local invasion or distant metastasis is present on imaging

Ovarian Teratoma complex cystic and solid pelvic mass containing two teeth and fat65

Contrast-enhanced coronal CT images of the abdomen and pelvis, demonstrate a large predominantly cystic left adnexal mass containing multiple septations almost completely occupying the abdomen (black arrow). The twisted vascular pedicle in the left lower quadrant demonstrates a whirlpool sign (white arrows)66

Adnexal torsion Can occur at any age but is most frequent in the first two decades of life. The affected ovary may be normal or containing a cyst or tumour.

Patients present with acute lower abdominal pain and vomiting.Ultrasound demonstrate an enlarged swollen ovary with peripheral cysts and free fluid in the pouch of DouglasDoppler signal is usually absent.

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder:

macroglossia - most common clinical finding omphalocoelelocalised gigantism / macrosomiahemihypertrophycardiac anomaliespancreatic islet cell hyperplasiaorganomegaliesnephromegalyhepatosplenomegaly

AssociationsWilms tumourNeuroblastomaHepatoblastomaRhabdomyosarcoma

Claw signIt refers to the sharp angles on either side of the mass which the surrounding normal parenchyma forms when the mass has arisen from the parenchyma. As such, normal parenchyma extends some way around the mass.

Examples where a claw sign is useful include:

meningioma vs intraparenchymal brain tumourWilms tumour vs neuroblastomarenal angiomyolipoma vs retroperitoneal liposarcoma71

Thank You