A first report of a rare TP53 variant associated with Li-Fraumeni syndrome manifesting as invasive breast cancer and malignant solitary fibrous tumor

Background Li-Fraumeni is a rare autosomal dominant cancer predisposition syndrome. The basis is a germline mutation of TP53 gene which encodes tumor suppressor protein resulting in early onset of tumors, most often breast cancer, soft tissue sarcomas, brain tumors, adrenocortical carcinomas, and leukemia. Case report We present a case of a young woman with a positive family history for cancer diagnosed with malignant solitary fibrous tumor and luminal B-like invasive breast cancer. Breast cancer and sarcomas account for the majority of tumors associated with Li-Fraumeni syndrome, yet solitary fibrous tumor is a rare clinical entity with no established guidelines for treatment. Even though both primary tumors were successfully resected, the sarcoma relapsed in the form of lung metastases. The NGS analysis revealed single nucleotide variant (c.1101-1G>A) in TP53 gene, affecting the acceptor splice site at intron 10. Until now, only one case of this genetic variant has been documented with conflicting interpretations of pathogenicity. Conclusions The knowledge of TP53 mutation status is essential since the management of these patients requires different approach to avoid excessive toxicity due to the risk of developing secondary malignancy. Using the clinical criteria to screen for affected individuals facilitates appropriate early genetic counseling of patients and their families. Following the American College of Medical Genetics criteria, we believe that the reported single nucleotide variant (c.1101-1G>A) in TP53 gene should be considered pathogenic.