Differential Diagnosis for 42yo Female with Right Flank Pain and CT Showing Mild Hydronephrosis Secondary to Uterine Fibroid

• Single Most Likely Diagnosis
  • Uterine fibroid causing ureteral compression: This is the most direct explanation given the CT findings, which explicitly mention the hydronephrosis is secondary to a uterine fibroid. The fibroid's size and location can compress the ureter, leading to obstructive uropathy and subsequent hydronephrosis.
• Other Likely Diagnoses
  • Kidney stone: Although the CT shows hydronephrosis due to a fibroid, kidney stones are a common cause of flank pain and hydronephrosis. The presence of a fibroid does not rule out the possibility of a stone, especially if the stone is causing additional obstruction.
  • Pyelonephritis: Infection of the kidney can cause flank pain and could be a secondary complication of the obstructive uropathy caused by the fibroid.
  • Ureteropelvic junction (UPJ) obstruction: This is a condition where there is a blockage at the junction where the ureter attaches to the kidney. While less likely given the fibroid's role, it's a possible cause of hydronephrosis.
• Do Not Miss Diagnoses
  • Ovarian torsion: Although less common, ovarian torsion can cause severe pain and is a surgical emergency. The presence of a uterine fibroid does not exclude this possibility, especially if the fibroid is large and potentially displacing or torsing the ovary.
  • Ectopic pregnancy: In a woman of childbearing age, ectopic pregnancy must be considered in the differential diagnosis of acute abdominal or pelvic pain, despite the presence of a known fibroid.
  • Ureteral injury: This could be a complication of the fibroid or a separate issue, such as from a surgical procedure or trauma, and would require prompt intervention.
• Rare Diagnoses
  • Retroperitoneal fibrosis: A rare condition characterized by the proliferation of fibrous tissue in the retroperitoneum, which can encase and obstruct structures such as the ureters.
  • Genitourinary malignancies: Although rare, cancers of the uterus, ovaries, or kidneys could potentially cause hydronephrosis by obstructing the ureters.
  • Endometriosis involving the ureter: Endometriosis can rarely involve the ureters and cause obstruction leading to hydronephrosis.