Search engines such as PubMed and MEDLINE were browsed for English-language articles since 1989 using a list of keywords, as well as references from review articles. Search terms were NF1, osteosarcoma, leiomyosarcoma, somatostatinoma and GIST. Data were summarized in a table at the end of the Results section.
In our four NF1 cases, there were one osteosarcoma, one leiomyosarcoma, one somatostatinoma and GIST and one GIST. NF1 was diagnosed at an adult age when these patients were admitted to our oncology department. The results generated by the literature search yielded 75 articles about NF and GIST. We summarized the clinical characteristics of 43 patients with NF1 and somatostatinoma. Forty-five articles involving NF and osteosarcoma were found, and of these, 26 involved NF1; from these articles, we identified the clinical features of 8 patients. Twenty-five articles were found concerning NF1 and leiomyosarcoma, and of those, we summarized the clinical features of 15 patients.
Here we reviewed somatostatinomas, GISTs, osteosarcomas and leiomyosarcomas occurring in NF1 patients. Patients with NF1 who present with gastrointestinal symptoms, should be carefully evaluated carefully with a high index of suspicion of potential GISTs, periampullary and duodenal tumors. Patients with pathological fractures or bone pain along with NF1 should be carefully screened for malignant bone tumors. Patients with NF1 can develop leiomyosarcoma less frequently than other malignancies, but the association of uterine leiomyoma and NF1 may not be fortuitous. Somatic mutations were defined for frequent tumors, including neurogenic tumors and GISTs but not for sarcomas due to the complexity of underlying mechanisms of the disease and tumorigenesis. Based on the findings; all NF patients can develop malignant tumors, including the less frequently observed ones. Therefore, we recommend that new genetic studies should be performed for rare malignancies in cases of NF1.