Tele Early Symptoms Of Childhood Cancer Ism . These signs may be present in the abdomen, armpits, pelvis, neck or chest. I ncreased swelling or persistent pain in bones, joints, back, or legs l ump or mass, often in the abdomen, neck, chest, pelvis, or armpits d evelopment of excessive bruising, bleeding, or rash c onstant, frequent, or persistent infections a whitish color behind the pupil n ausea that persists or vomiting without nausea childhood cancer signs and symptoms United Cancer Support Foundation from unitedcsf.org In any case, common indications of brain tumors are: Cancer in children is not common, but it’s important to have your child checked by a doctor if they have unusual signs or symptoms that do not go away, such as: Signs for childhood cancers can include lumps, masses or swelling that a doctor finds during an exam.