A cluster of diagnoses involving an extremely rare form of cancer has left families in an affluent Orange County community searching for answers after multiple children were diagnosed with the same disease. Families in Ladera Ranch say at least six children from the area have been diagnosed with Ewing sarcoma, a rare bone and soft tissue cancer that affects only about 200 to 240 children and teenagers nationwide each year, according to the American Cancer Society. Among them was 17-year-old Brody Matteson, who died after battling the disease. “He was an outdoor kid. There was a time to be outside, that was…