The evaluation of right lower quadrant (RLQ) abdominal pain in pediatric pa
tients with malignancy can be difficult. However, since the mortality rate
from peritoneal infections in these patients is very high, the differential
diagnosis of RLQ peritoneal irritation, mainly of acute appendicitis (AA)
versus neutropenic enterocolitis (NE), is crucial. Three cases of pediatric
patients with malignancy demonstrating these difficulties are represented
to enlighten this problem. The first patient died of multiorgan failure aft
er operation for perforated appendicitis without generalized peritonitis. T
he second had a severe life-threatening postoperative complication because
of delayed diagnosis of acute appendicitis. The third patient with malignan
t pelvic spread, underwent an unnecessary abdominal exploration for suspect
ed AA. In all these cases and probably in many others, the clinical outcome
could have been different if a previous incidental appendectomy had been p
erformed during the primary abdominal operation. Incidental appendectomy in
oncologic patients is recommended to facilitate the differential diagnosis
of RLQ pain and to exclude the diagnosis of AA.