Which postoperative complication typically develops 2 to 6 months after renal surgery and presents as an encapsulated lymphatic collection between the kidney and bladder?

Which postoperative complication typically develops 2 to 6 months after renal surgery and presents as an encapsulated lymphatic collection between the kidney and bladder?

• A. Lymphocele
• B. Urinoma
• C. Pyonephrosis
• D. Hydronephrosis

Answer: (A)

The main idea here is recognizing a postoperative lymphatic fluid collection that forms months after renal surgery. When lymphatic channels are disrupted during the operation, lymphatic fluid can leak into the retroperitoneal space. Over weeks to months this fluid accumulates and becomes encapsulated by a fibrous wall, creating a lymphocele. Because it’s a closed, walled-off collection, it often sits between the kidney and the bladder—the perinephric/retroperitoneal region—and its appearance is timed in the 2- to 6-month window after surgery. This timing and encapsulated nature help distinguish it from other postoperative collections. Imaging typically shows a well-defined, anechoic or hypoechoic fluid collection with a surrounding wall, separate from the renal collecting system. If the lymphocele is large or symptomatic, it can compress nearby structures, potentially causing obstruction or hydronephrosis, and may require drainage or surgical management. Why the others don’t fit: a urinoma is a urine collection from a leak in the collecting system and usually presents sooner after surgery; pyonephrosis is infected fluid within the dilated kidney and shows debris and infection signs rather than a simple encapsulated fluid gap; hydronephrosis is dilation of the kidney due to obstruction, not a discrete encapsulated fluid collection.

The main idea here is recognizing a postoperative lymphatic fluid collection that forms months after renal surgery. When lymphatic channels are disrupted during the operation, lymphatic fluid can leak into the retroperitoneal space. Over weeks to months this fluid accumulates and becomes encapsulated by a fibrous wall, creating a lymphocele. Because it’s a closed, walled-off collection, it often sits between the kidney and the bladder—the perinephric/retroperitoneal region—and its appearance is timed in the 2- to 6-month window after surgery. This timing and encapsulated nature help distinguish it from other postoperative collections.

Imaging typically shows a well-defined, anechoic or hypoechoic fluid collection with a surrounding wall, separate from the renal collecting system. If the lymphocele is large or symptomatic, it can compress nearby structures, potentially causing obstruction or hydronephrosis, and may require drainage or surgical management.

Why the others don’t fit: a urinoma is a urine collection from a leak in the collecting system and usually presents sooner after surgery; pyonephrosis is infected fluid within the dilated kidney and shows debris and infection signs rather than a simple encapsulated fluid gap; hydronephrosis is dilation of the kidney due to obstruction, not a discrete encapsulated fluid collection.