What are some clinical differential diagnoses for right sided abdominal pain?
Cholecystitis, appendicitis, ureteric colic, diverticulitis (more commonly left sided), omental infarction / epiploic appendagitis...
What other significant finding is present?
Large left sided renal cell carcinoma.
Are renal cell carcinomas usually painful? How do they classically present?
No, in general RCC are painless, and classically present with haematuria.
The vermiform appendix is thickened and surrounded by extensive stranding in the surrounding fat. There is no abscess formation or free intra-abdominal air.
Additionally left upper pole renal mass is present consistent with a renal cell carcinoma. The fat plane between the left crus of the diaphragm and the splenic artery above the mass is lost, which is suspicious for local invasion.