Pediatric Imaging Patterns

A 3-year-old boy from Delhi presents with a 2-week history of progressive abdominal distension, vomiting, and constipation. On examination, he is afebrile with a palpable abdominal mass in the right flank. Abdominal ultrasound shows a large heterogeneous mass with a "target sign" on transverse section. CT abdomen with contrast reveals a mass with alternating layers of soft tissue and fat density. What is the most likely diagnosis?

A 6-month-old female infant from Delhi presents with a 3-week history of progressive respiratory distress, feeding difficulty, and recurrent respiratory tract infections. Chest radiograph shows a large, well-defined, radiolucent mass occupying the left hemithorax with mediastinal shift to the right and compression of the left lower lobe bronchus. The mass is filled with air-fluid levels and contains multiple cystic spaces of varying sizes. Ultrasound of the abdomen is normal. What is the most likely diagnosis?

A 3-year-old boy from rural Maharashtra presents with a 2-week history of progressive abdominal distension, constipation, and failure to pass meconium beyond the neonatal period. Physical examination reveals a distended abdomen with visible peristaltic waves. Abdominal radiograph shows dilated loops of small bowel with air-fluid levels. Contrast enema reveals a transition zone in the rectosigmoid region with a narrow distal segment. What is the most likely diagnosis?

A 6-month-old girl from Delhi presents with recurrent episodes of projectile vomiting for 3 weeks. The infant appears dehydrated with visible peristaltic waves moving from left to right across the epigastrium. On palpation, a firm, olive-shaped mass is felt in the epigastric region. Abdominal ultrasound is ordered. What is the expected ultrasound finding?

A 3-year-old boy from rural Maharashtra presents with a 2-week history of progressive abdominal distension, constipation, and explosive diarrhea alternating with periods of obstruction. On examination, the abdomen is grossly distended with visible peristaltic waves. Plain radiograph of the abdomen shows a 'transition zone' with a narrow segment of colon in the rectosigmoid region, proximal colonic dilatation, and absence of gas in the distal rectum. What is the most likely diagnosis based on these imaging findings?