Gallstones with CBD dilatation. Be done.

See if the entity u mentioned is Choledochal cyst Than surgery will depend on the type Of cyst Rest don't go on H/o of pain is not there or any symptoms Malignant changes chances are high In this case So do the needful as early as possible

This is a complicated case, try to read carefully and understand. When you got USG for gastroenteritis (GE) it reported cholelithiasis. For cholelithiasis, the only treatment is cholecystetomy or else you can manage it conservative (i.e. with medications with chances for pain on and off). But then, along with gall stone there was also CBD dilation without jaundice, which required MRCP for further evaluation.  This revealed choledochal cyst. For choledochal cyst the definite procedure is cyst excision and reconstruction.  Reconstruction can be done either by roux-en-y hepaticojejunostomy or by hepaticoduodenostomy. Among these roux-en-y hepaticojejunostomy is better option. But, both these procedures are major surgeries and to be done in surgically fit patient. Also, you are saying that there are no major symptom (then what is the need of such major procedure???) Surgery is needed as these cases have high potential to turn towards malignancy or recurrent cholangitis. I hope, i explained everything.

Roux-, y for CD  Cyst Treat gastroenteritis accordingly