<prompt> Doughnut sign is seen inIntussusceptionCarcinoma colonCHPSVolvulus  <response>: .CONGENITAL HYPEROPHIC PYLORIC STENOSIS is hyperophy of musculature of pyloric antrum, especially the circular muscle fibres, causing primary failure of pylorus to relax. Duodenum is normal. Clinical features of congenital pyloric stenosis 1. Vomiting 2. VGP 3. Palpable mass 4. Constipation and dehydration Diagnosis is established by -- Clinical examination. -- US abdomen very useful--Doughnut sign. Pyloric muscle 4 mm or more in thickness. Length of pyloric canal 1.8 cm. -- Barium meal shows obstruction. ref:SRB;S manual of surgery,ed 3,pg no 752 