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

Renal Masses

Congenital Pevicalyceal dilatation

Infection Neoplasm Vascular

Multicystic Dysplastic kidney

  Abscess Malignant: Wilm’s tumour

Renal vein thrombosis

PUJ obstruction

  Focal nephritis Benign Haematoma

Cystic renal disease

  Xanthogranulomatous pyelonephritis

Wilm’s tumour• It arises from the primitive metanephric

epithelium • Bilateral synchrous tumours occur in 5-10%.• Nephroblastomatosis as precursor• Increased incidence

sporadic aniridia,hemihypertrophy,Beckwith-wiedemann syndorme,Drash syndrome,Horseshoe kidney,Family history.

Presentation

•Mostly present as asymptomatic mass•Abdominal pain•Haematuria•Fever•Hypertension

Imaging• On 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 atrium

• On 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 T2

• The lung is commonest site for metastases.

Tumor stagingDetermined by imaging and surgical findings.• Stage 1:Encapsulated tumor completely excised.• Stage 2:Extends beyond the kidney, completely excised• Stage 3:Residual tumor confined to abdomen and nodes• Stage 4:Haemetogenous metastasis• Stage 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.

Treatment

•The main types of treatment that can be used for Wilm's tumor are:

•Surgery•Chemotherapy•Radiation therapy

Nephrectomy followed by chemotherapy•Postoperative radiation therapy for stage

II and IV lesions

•Renal cell carcinoma is very rare in young children but sometimes occurs in older children and adolescents

•The 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.

Neuroblastoma•Malignant tumor of neural crest cells•Commonest extracranial solid malignant

tumor•Approximately 70% originate in the

abdomen of which 2/3rd arise in adrenal,20% in the chest and 10% in the head and neck

•May present as palpable abdominal mass or non specific symptoms

•50 to 60% of all neuroblastoma cases present with metastases

Radiological imaging• Ultrasound 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

Staging

Involve the radiological, surgical and bone marrow aspirate:• Stage 1:confined to organ of origin• Stage 2: extending beyond the organ of origin,

unilateral nodal disease• Stage 3:extending across the midline, bilateral

nodal disease• Stage 4: distant metastases• Stage 4s: age<1year,localized primary(stage 1 or

2 metastases to liver, skin and/or bone marrow)

•Treatment options for neuroblastoma largely depend on the location and size of the tumor and usually involve multimodal therapy

•1.Surgery•2.Radiation therapy•3.Chemotherapy•Immunotherapy•Bone marrow transplant

Hepatobiliary masses• Accounts for 6% of abdominal masses• 2/3rd are malignant and 1/3rd are benign.

HepatoblastomaMost common malignant hepatic tumor

• Majority present under 2 years• No association with cirrhosis• Increased risk with beckwith wiedemann syndrome,

affected siblings, familial polyposis coli and trisomy 18.

usually present with an abdominal mass

Imaging•On ultrasound single or multiple hyperechoic

masses with distortion of the adjacent vascular architecture,hepatoblastomas usually are highly vascular

•On CT heterogeneous low attenuation lesion are seen with areas of necrosis and hemorrhage and often containing coarse calcification

•Vascular and tumor thrombus strongly suggest malignancy

•Lung is the most frequent site of metastases

Management

•Chemotherapy•Radiotherapy•Resection and transplantation

Liver metastases

•Metastases to the liver are more common than primary hepatic tumours and most frequently associated with the neuroblastoma, Wilm's tumour, lymphoma and leukemia

Ultrasound of liver metastases can have a variety of appearances•hypoechoic: most common ~ 65%•Hyperechoic•peripheral halo•Calcified•Cystic•poorly defined (infiltrative)

Infantile haemangioendothelioma •common benign hepatic mass in newborn.

May be multifocal or solitary.

Imaging

• Infantile haemangioendotheliomas have a variable sonographic appearance and may be either hypoechoic or hyperechoic or may have mixed echogenicity

• Colour Doppler sonographic evaluation will show increased flow.

• On CT enhancement is typical • On MRI lesions are low signal on T1 and high on

T2 with large vascular signal voids

Choledochal CystsCongenital dilatations of the biliary tree• Most cause symptoms in childhood and adult life.

There are four types:• Type 1A: Fusiform dilatation of the CBD below the cystic

duct• Type 1B: Fusiform dilation of the common hepatic duct

and CBD• Type 2: Eccentric diverticulum off the CBD• Type 3: Choledococele-Dilatation of the distal intramural

portion of the CBD• Type 4: Caroli’s disease-saccular dilations of the hepatic

bile ducts

Complications include cholangitis, biliary calculi, pancreatitis and biliary cirrhosis.

•On ultrasound or CT the biliary tree dilatation or cyst can be seen.

•99mTc-HIDA scinitraphy will show accumulation of tracer within the cyst.

•Percutanous or endoscopic cholangiography and MRCP are helpful in preoperative planning.

Pancreatic masses

•Pancreatic pseudocysts occurring as the sequelae of previous pancreatitis or trauma

•True epithelial line congenital pancreatic cysts are less common

•Primary pancreatic tumours are rare in childhood including the pancreticoblastoma,papillary epithelial neoplasm and endocrine adenomas

Splenic massesCauses of splenomegaly

Infections Mononucleosis,tuberculosis,septicemia,typhoid,malaria

Portal hypertension

Haemolytic anemia

Thalassaemia

Haematological malignancies

Leukemia,lymphoma

Infiltrative disorders

Gaucer’s,niemann-pick,Langerhans cell histiocystosis

Collagen vascular disorders

Rheumatoid arthritis

CCF  

• Asplenia and polysplenia occurs as part of heterotaxy syndrome.(Situs ambiguus)

• Asplenia is associated with right isomerism,malrotation and severe congenital cardiac defects with majority of infants dying in the first year of life

• Polysplenia in which multiple well defined masses are found in the left upper quadrant.

• Wandering spleen is ectopic location outside the left upper quadrant

Wandering spleen

Focal splenic lesions

•Splenic cysts may be congenital or acquired secondary to trauma, infarction or hydatid disease.

•Benign focal splenic masses include haemangiomas,lymphangiomas, AVM and hamartomas

Gastrointestinal Masses

•Duplication cysts and mesenteric/omental cysts

•Commonest malignancy is Burkitt’s non Hodgkin’s lymphoma ▫Ill defined mass of adherent bowel loops

with infiltration of the adjacent mesentery and with lymphadenopathy

Pelvic masses

•Rhabdomyosarcoma•Sacrococcygeal teratomas•Ovarian masses•Pelvic inflammatory disease

Rhabdomyosarcoma

•Commonest pediatric soft tissue sarcoma•Pelvis most frequent site of origin•In boys mostly arises from the prostate or

bladder base•In girls from the urinary bladder, uterus

or vagina

•These are aggressive tumors•Invasion of adjacent viscera and pelvic

wall•Distant spread to lymph nodes, lung and

bone

Ultrasound •shows heterogeneous well-defined

irregular mass of low to medium echogenicity

CT•soft tissue density•some enhancement with contrast•adjacent bony destruction seen in over

20% of cases

Ovarian tumors

•65% are benign and 35% are malignant •Ovarian teratomas usually present at

puberty and 90% are benign•The majority of ovarian malignancies are

germ cell tumour•Most are large >15cm at presentation

Serology

•CA-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

Imaging

•On ultrasound solid and cystic component can be demonstrated

•CT can demonstrate the solid-cystic mass with fat and calcific components

•It is not possible to determine whether a mass is benign or malignant unless local invasion or distant metastasis is present on imaging

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 Douglas

• Doppler signal is usually absent.

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

• macroglossia - most common clinical finding • omphalocoele• localised gigantism / macrosomia• hemihypertrophy• cardiac anomalies• pancreatic islet cell hyperplasia• organomegalies• nephromegaly• hepatosplenomegaly

Associations

•Wilms tumour•Neuroblastoma•Hepatoblastoma•Rhabdomyosarcoma

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