De novo malignances in pediatric organ transplant recipients.

A study of 10813 types of cancer that occurred in 10151 organ transplant recipients showed that the pattern of malignancies that occurred in pediatric recipients was very different from the general pediatric population and from adult recipients. Tumors (527) occurred in 512 pediatric patients (aged 18 years or less), and 9639 adults developed 10286 neoplasms. Post-transplant lymphoproliferative disease (PTLD) was the predominant neoplasm in pediatric recipients and comprised 52% of all tumors compared with 15% in adult recipients. Eighty-four percent of PTLD in the former patients presented during childhood. There was a disproportionately high incidence among nonrenal allograft recipients compared with renal recipients (81% vs. 31% of all tumors). The second most common malignancy in pediatric patients was skin cancer (19% of tumors), but this was less frequent than in adult recipients, in whom it comprised 39% of neoplasms. Only 16 pediatric patients (16%) with skin cancers developed their tumors during childhood (6 had malignant melanomas), with an average time of appearance after transplantation of 126 months (range 5.5-292). Malignant melanomas were more common in pediatric than adult recipients (12% vs. 5% of skin cancers), as were lip cancers (23% vs. 12%). Spread to lymph nodes was also more common in pediatric than in adult recipients (9% vs. 6%). Sarcomas comprised 4% of tumors compared with 1% in adults. Carcinomas of the vulva and perineum also comprised 4% of tumors. Females outnumbered males in a ratio of 8.5:1. These tumors appeared beyond childhood at an average of 142 months (range 42-262 months) post-transplantation. Other cancers observed in recipients transplanted during childhood were thyroid carcinomas (15), Kaposi's sarcomas (15), carcinomas of the liver (13), leukemias (13), carcinomas of the cervix (10), brain tumors (7), renal carcinomas (7), ovarian carcinomas (5), and miscellaneous tumors (19). Of all 527 malignancies, 314 (60%) appeared during childhood and 213 (40%) manifested themselves between the ages of 19 and 40 years. By far the most common tumor diagnosed during childhood was PTLD, which comprised 230 of the 314 (73%) malignancies.