Oncologic manifestations of neurofibromatosis type 1 in Korea.

Purpose: The aim of this study was to investigate the incidence and spectrum of malignant tumors in Korean neurofibromatosis type 1 (NF1) patients.

Methods: We retrospectively reviewed 125 patients who were diagnosed with NF1 at a single institution from 1995 to 2010. The incidence, location, histologic type, and radiologic findings of malignant tumors as well as development of multiple primary tumors were analyzed.

Results: Eighteen malignant tumors occurred in 16 patients (12.8%) among 125 Korean NF1 patients; 9 carcinomas, 8 sarcomas and 1 central nervous system (CNS) tumor. Five tumors were of nervous system origin and 13 were non-nervous system tumors. The locations of the tumors were as follow: 1 CNS, 2 lung, 3 breast, 3 stomach, 3 small bowel, 1 colon, 1 liver, 1 uterus, 1 neck, and 2 in extremities. Three malignant peripheral nerve sheath tumors (MPNSTs) occurred at the neck and extremity, and one in the liver. All three gastrointestinal stromal tumors (GISTs) had multiple tumors in the jejunum, and one MPNST and one pheochromocytoma were accompanied in two GISTs. Multiple primary tumors, benign or malignant were reported in 4 patients (25.0%), synchronously or metachronously.

Conclusion: Korean NF1 patients had a high risk of developing malignant tumors. The common malignant tumors in Koreans such as breast, lung and stomach cancers developed frequently in addition to the NF1-related tumors such as MPNST or GIST.