Random Radiology fRiday: Oh Granny, what a big gallbladder you have

Ready for a random quick one? Welcome to Friday!
Gallbladder Hydrops: 
- >4cm transverse, >9cm longitudinal on US
- Can be seen in fasting patient (no symptoms)
- When pathologic, may be secondary to:
= chronic impacted stone (neck/cystic duct), tumor/polyp, extrinsic compression
Kawasaki: w/in first 2wks of illness; acalculous; 2/2 periportal inflammation to cystic duct (treatment is supportive)
= Mesenteric adenitis (look for RUQ pain next time you see this)
parasites (Ascaris)
- filled with mucoid or watery secretions instead of bile; 
= may be up to 1.5L
- labs usually WNL; mild leukocytosis, no real change in LFTs/bili (unless CBD obstruction); 
- overdistension can lead to empyema/gangrene/perforation
- in most cases, treatment is cholecystectomy (even if acalculous)
Hydrops with GB wall thickening, no obvious gallstone on this cut. (The case is a teenager with mononucleosis w/ splenomegaly and LAD).
Remember Courvoisier's Law: if the GB is palpably enlarged w/ jaundice but NONtender = unlikely to be due to gallstones (this is not 100% true but a good rule of thumb)