JEONJU — Surgeons in Jeonju, South Korea, discovered a 10-inch tapeworm in the peritoneal cavity of a 71-year-old man during a routine hernia repair surgery on his right groin. The unexpected finding led to a diagnosis of sparganosis, a rare parasitic infection caused by the larval form of the tapeworm Spirometra erinaceieuropaei.

The patient had presented with only a painless bulge in his right groin and reported no other symptoms prior to the operation. Pre-operative laboratory tests showed no eosinophilia, a common indicator of parasitic infection, and there was no evidence of localized pain, inflammatory reaction, or neurological symptoms suggestive of parasitic disease, according to doctors Chang-Seop Lee and Yeon Jun Jeong of Jeonbuk National University Medical School in Jeonju.

After removal, the extracted tapeworm was observed undulating on the surgical table, confirming its viability at the time of extraction. A polymerase chain reaction (PCR) test later classified the organism as Spirometra erinaceieuropaei, leading to a definitive diagnosis of sparganosis. Following the surgery, the patient was administered antiparasitic drugs and reported feeling well 45 days post-operation.

This case marks the second time a tapeworm has been found in the same patient. Four years earlier, during surgery to repair a left inguinal hernia, a 7-inch tapeworm was incidentally discovered and removed. At that time, the patient did not receive antiparasitic medication. The recurrence—and location shift from the left to the right side of the abdomen—underscores the parasite’s migratory nature within the human body.

The patient recalled consuming raw snake meat on multiple occasions approximately 50 years ago during his military service. He had done so based on the belief that raw snake meat conferred health benefits or increased stamina. This historical exposure aligns with known transmission routes for sparganosis, which can occur when humans eat undercooked meat from infected snakes or frogs or drink water contaminated with infected crustaceans.

Chang-Seop Lee and Yeon Jun Jeong emphasized the unusual nature of the presentation. “This case represents an exceptionally unusual clinical presentation and illustrates the prolonged survival and migratory potential of spargana in humans,” they stated. They added that sparganosis should be included in the differential diagnosis for patients with a history of consuming raw reptiles or amphibians in endemic regions. They also stressed that “[c]areful inspection of unexpected intraoperative findings and appropriate pathological or molecular confirmation are important for establishing the diagnosis.”

Sparganosis is a rare condition globally, with approximately 2,000 cases reported, primarily in Southeast Asia. However, endemic regions also include parts of North America. The infection typically begins when eggs from infected cats or dogs enter freshwater environments. Microscopic crustaceans or crayfish then ingest the eggs, where they develop into larvae. Frogs or snakes that consume these crustaceans become intermediate hosts, harboring spargana larvae. The life cycle continues when these infected animals are eaten by definitive hosts like cats, dogs—or occasionally, humans.

Human infection can also occur through the use of frog tissue as poultices on open wounds. Clinically, sparganosis often presents as a subcutaneous nodule that may become tender, inflamed, bleed, or proliferate over time. In about 20% of cases, the parasite migrates to the brain or central nervous system, where it can cause severe complications and may be fatal. Notably, the infection can remain asymptomatic for extended periods, with clinical manifestations appearing anywhere from weeks to decades after initial exposure.

Bruce E. Hirsch, MD, of Northwell Health in Manhasset, New York, commented on the case, noting the absence of tissue damage despite the parasite’s size and location. “Not only does the tapeworm look extremely comfortable inside the peritoneal cavity, but the peritoneal cavity looks fine,” he said. His observation highlights the insidious nature of some parasitic infections, which can persist without triggering typical immune or inflammatory responses.

Why It Matters

This case illustrates the long latency and diagnostic challenges associated with sparganosis, a condition that may go undetected for decades. The patient’s asymptomatic presentation and normal pre-operative labs demonstrate that standard screening may miss parasitic infections with atypical or dormant courses. Given global travel and dietary practices—including the consumption of raw or undercooked wildlife—physicians in non-endemic regions must consider sparganosis in patients with relevant exposure histories.

Published research, including a 2015 study in PLoS Neglected Tropical Diseases titled “Characterization of Spirometra erinaceieuropaei Plerocercoid Cysteine Protease and Potential Application for Serodiagnosis of Sparganosis,” has sought to improve diagnostic tools for this rare infection. However, as noted in reports of unconfirmed cases—such as one in Missouri where antibody testing was unavailable—diagnosis often relies on surgical discovery and molecular confirmation, reinforcing the need for heightened clinical suspicion in at-risk individuals.