Surgeons Find "Mouse" in Patient's Abdomen During Surgery

An unusual surgical case left doctors speechless at a hospital in Jordan. During a routine laparoscopic operation to treat a varicocele in a 22-year-old man, surgeons found a smooth, egg-shaped object floating freely in the abdominal cavity.

The object, which could be moved from one side of the abdomen to the other with a simple touch, was removed via the laparoscope and sent to the laboratory. Histological analysis revealed it was calcified necrotic adipose tissue, known in medical jargon as a "peritoneal loose body" or "peritoneal mouse."

The case was published in the American Journal of Case Reports on August 27, 2026. The patient, in perfect health and with no prior abdominal surgeries, had come to the hospital to treat the swelling of the scrotal veins that was causing him discomfort.

The "peritoneal mouse" is a rare pathological formation that develops in the abdominal cavity. It consists of adipose tissue that, for reasons not always clear, detaches from its original site, dies (becomes necrotic), calcifies, and begins to move freely within the peritoneum, the membrane lining the abdominal organs.

These free bodies can form spontaneously or following trauma, surgical procedures, or inflammatory processes. Their presence is often asymptomatic and is discovered accidentally during examinations or operations for other reasons, as in the described case. The term "mouse" comes from the English word and refers to the object's mobility within the abdomen.

Although rare, these cases have been documented in medical literature for years. Their removal is generally recommended to avoid future complications, such as intestinal obstructions or misdiagnoses during future examinations. The Jordanian case is particularly interesting because the patient had no surgical history that could explain the formation of the free body.