ABSTRACT Abdominal tumors are one of the most common types of pediatric cancer. Therefore, they should always be included in the differential diagnosis of abdominal masses. Here, we present the case of a child whose initial hypothesis of diagnosis contemplated this possibility. Later, it was demonstrated that the abdominal mass found was secondary to a common parasitosis. A 2-year old, moderately malnourished and pale white boy was referred with a history of a rapidly growing, well-limited, middle abdominal mass. The mass was 10 by 3 cm, hard and poorly movable, apparently involving both abdominal rectus muscles. A complete resection was performed, revealing an abdominal wall abscess, with intense eosinophilic proliferation, secondary to a local and intense reaction to innumerous Ascaris lumbricoides eggs. Extra luminal infestations with Ascaris, that usually form peritoneal granulomas have been previously described. However, neither external trauma nor fistula, that could explain the superficial presence of the eggs, was found. This description reinforces the relevance of infectious diseases within the differential diagnosis of abdominal masses, particularly in areas with high prevalence of parasitic infestations.