Toxocara canis Mimicking a Metastatic Omental Mass from Sigmoid Colon Cancer: A Case Report

Toxocara canis is an important roundworm of canids and a fearsome animal parasite of humans. Human infections can lead to syndromes called visceral larva migrans (VLM), ocular larva migrans, neurotoxocariasis, and covert toxocariasis. VLM is most commonly diagnosed in children younger than 8 years of age, but adult cases are relatively frequent among those infected by ingesting the raw tissue of paratenic hosts in East Asia. This research reports the case of a 59-year-old man with sigmoid colon cancer, who visited our institution for surgery. An intraperitoneal mass was found on preoperative computed tomography, and it was thought to be a metastatic mass from sigmoid colon cancer. A postoperative histologic examination and serum test showed eosinophilic granuloma due to toxocariasis. Diagnosis of VLM is often difficult and highly suspicious in adults. Researchers suggest, although rarely, that VLM be included in the differential diagnosis as a cause of intraperitoneal tumors.