38thAnnual Late (Dr) .P. K. Bora MemorialOration.Abdominal Mass Lesion in Paediatric age group- A viewthrough Radiologist’s eye.Dr.Karuna Hazarika,Professor & HOD Radiology,Silchar Medical College.Introduction :Abdominal masses are most common in children under the age of 5years. Mostabdominal masses in neonates are retroperitoneal and of kidney origin. The older thechild the more likely the mass represents a malignant process. The diagnosticevaluation of a mass lesion of abdomen in children is a challenging problem. The role ofRadiologist to select a appropriate tool for diagnosis depends on the presentingfeatures of the patient. The role is to identify the precise location the origin and extent ofpathologic process with a minimal number of imaging procedure with little discomfort tothe patient.Three decades earlier detailed history of the disease , clinical judgment and laboratoryinvestigations were the most important and often only tool to come to a diagnosis. Nowa days multitude of imaging modalities like plain radiograph ,Contrast studies of GIT andothers ,USG, CT,MRI, Angiography, Nuclear Scan etc. play a vital role in diagnosis ofabdominal mass lesion. This helps the Radiologist to achieve the diagnosis for bettercare of the patient with judicious selection of techniques.Pathological Conditions :Most common lesion in the child to present as a mss is Renal lesion (55%)-Hydronephrosis, Cystic Disease, Multicystic dysplastic kidney, polycystic kidney,Nephroma ,Nephroblastomatosis, This could be unilateral or bilateral. Genital /pelvic (15%)- teratoma, Ovarian cyst, Hydrometrocolpos ,Obstructed bladder etc. Outof Non renal Retroperitoneal lesion(10%) are Adrenal Haemorrhage,Neuroblastoma, Teratoma etc. GIT lesion(15%) are Hypertrophic pyloric stenosis,Duplication cyst, Mesenteric/omental cyst, Volvulusetc. Hepatoboiliary & Pancreaticlesion(5%) includes Heatoblastoma, Haemangioendothelioma, Metastasis , Choledocalcyst, Pancratic pseudo tumour, Pancreatic blastoma etc. Lesions in older child includeRenal –Wilm,’s Tumour, Hydronephrosis,Cystic disease, Non renal retroperitoneal(23%) are Neuroblastoma, Teratoma etc. GIT lesions are Appendeceal abscess,Lymphoma etc. Hepatic lesions lioke Hepatoblastoma, HCC, etc. Genital lesion areOvarian cyst, Teratoma, Hydrometro-colpos. EtcC Adrenal Haemorrhage,
Neuroblastoma, Teratoma etc. GIT lesion(15%) are Hypertrophic pyloric stenosis,Duplication cyst, Mesenteric/omental cyst.Radiological Technique: The imaging modalities available today for the evaluationof abdominal mass in children are :Plain RadiographsContrast studiesUltrasonography (USG)Computed tomography (CT)Magnetic resonance imaging (MRI)AngiographyNuclear scanChoice of imaging modalities :The presenting symptoms of a patient govern to a large extent the type of initialinvestigation performed. The radiologists have to take the judicious decision to selectthe appropriate imaging technique to achieve the diagnosis for better care of thepatient. Thus in a child with an abdominal lump US is the initial investigation of choice.As the details discussion of various findings of different lesions in different imagingtechnique is beyond the scope of this article ,a brief review of importance of differentimaging technique in evaluation of abdominal mass lesions in children will bepresented.Plain radiograph :Plain radiographs do not have the significant role in the diagnostic evaluation of patientwith abdominal mass except in certain clinical situations where patient with atypicalpresentation like bowel obstruct ion. Mass lesion with calcification, e.g. teratoma ,hepatoblastoma, pancreatoblastoma, neuroblastoma etc. plain radiographs arediagnostic. Pulmonary complication like basal pneumonia ,pleural effusion in abdominalmass lesion may be seen in chest radiographs.Contrast study: Clinical circumstances of the patient determine which contrast studyto be performed and in what fashion. The advancement of imaging technique andincreasing experience the diagnostic algorithms have changed dramatically in mostdiseases. The role of barium studies in the evaluation of GI masses in children has
declined significantly. However, in urogenital lesion contrast evaluation still plays somerole mostly in obstructive uropathies.Ultrasonography: US is the screening modality of choice in a child suspected tohave an intra abdominal mass. It is quick, easy to perform, rarely requires sedation. Itrequires no patient preparation and is non ionizing and cost effective. Lack of intraabdominal fat in infants and children allows better visualisation of intra abdominalstructures when compared with adults .It can give information about the fluid,presence and location of mass and nature of mass along with presence of adenopathy.It also guide for the further investigation and selection of imaging modality. ColourDoppler study helps in visualization of vascular flow to the organs along with pattern offlow.Computed Tomography: CT is an extremely accurate and fast imaging techniqueand is playing an increasing role in the radiological evaluation of abdominal masses inchildren. It can provide information about the site of involvement, information about thebowel wall, mesentery ,lymph node status, peritoneum, omentum and other solid organslike liver, kidney, spleen, pancreas and pelvic organs. Dynamic contrast study is moreaccurate in diagnosis of neoplastic lesions than US. With the advent of MDCT it is nowpossible to image the abdomen during the arterial and portal venous phases. Forpancreatic imaging the pancreas should be examined in “pancreatic phase’ only. Thisphase occurs in the interval between the arterial and portal venous phase at 40-70seconds after the bolus injection of contrast at a rate of 3ml/second. During this phasethere is maximum pancreatic parenchymal enhancement with accentuation of thelesion-to-pancreas contrast. Relative disadvantage of CT is the radiation exposure andit may require short sedation specially for children between 4 months to 4years. SpiralCT further decreases the scan time and allows the use of 3d reconstruction .Magnetic resonance imaging: MR imaging offers excellent soft tissue resolutionand delineation of vascular structures, multi planar ability, absence of ionising radiation.It is superior to both US and CT in characterizing the lesion and showing its extent,particularly vascular invasion. Because of expense, limited availability, motion artefactsfrom bowel peristalsis and compulsory sedation nearly all infants and children whichmakes its routine use impractical. It is usually reserved as problem solving modality.However due to lack f ionizing radiation , MR and MRCP are specially useful in thepaediatric population.Angiography : Angiography has limited role except for the vascular road-mapping oftumours when surgery or therapeutic embolisation is considered.Radionuclide scanning: Nuclear scanning is of liver and kidney are helpful indiagnosis of various mass lesions involving the liver and kidney. Tc 99m –Sulphurcolloid has sensitivity and specificity of 80-85 per cent each. It can be supplementedby single photon emission computed tomography (SPECT) which can detect lesion assmall as 1 cm.(90-95 % sensitivity and specificity). Radio iodide (MIBG) and Tc-99DMSA scan is useful in diagnosis of neuroblastoma and renal lesion and function.
Now the recent technique of PET –CT /Pet –MR help in detection of various abdominalmass lesions of children with follow up of treatment and prognosis. PET with FDGcan demonstrate metabolic activity in most neuroblastomas.Conclusion : The ultimate goal of imaging- better Patient care – depends oncoordinated efforts of radiologist, paediatrician and surgeon. The age of patient and thepresenting symptoms guides the initial imaging technique. Precise diagnostic evaluationallows selection of proper surgical and medical treatment to achieve our goal i.e.; ahealthy child.