TY - JOUR T1 - Recurrent Mandibular Giant Cell Lesion in Neurofibromatosis Type 1: Second Hit Mutation on the <em>NF1</em> Gene in the Osseous Lesion JF - Anticancer Research JO - Anticancer Res SP - 2945 LP - 2952 DO - 10.21873/anticanres.15777 VL - 42 IS - 6 AU - REINHARD E. FRIEDRICH AU - ANDREAS M. LUEBKE AU - ULRICH SCHÜLLER AU - CHRISTIAN HAGEL AU - FELIX K. KOHLRUSCH AU - ILSE WIELAND AU - MARTIN ZENKER Y1 - 2022/06/01 UR - http://ar.iiarjournals.org/content/42/6/2945.abstract N2 - Background/Aim: In the autosomal dominant hereditary disease neurofibromatosis type 1 (NF1), lesions of the jaw develop in isolated cases, which are diagnosed as central giant cell granuloma (CGCG). This study aimed to clarify the genetic basis of a bone lesion in a syndromic patient. Case Report: The NF1 patient had developed a CGCG that recurred after local excision. Blood and tumor tissue were studied for NF1 mutations using advanced molecular genetic methods. Examinations of blood and tumor tissue provided evidence of the constitutive mutation in both samples. A further mutation was detected in the tumor, which was interpreted as a somatic mutation. The detection of somatic mutation in the tissue was successful both on native and routinely fixed material. Conclusion: The study supports current assessments of CGCG as a benign neoplasm. In NF1 patients, the phenotype seems to imply bi-allelic loss of the NF1 gene. The detection of both mutations in routinely fixed tissue allows studies of archived tissue samples with this diagnosis. ER -