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Table 2　Consensus recommendations for the management of Li-Fraumeni syndrome12)Table 3　Comparison between previous reports and this case with c.216dupC in TP53 (p.Val73Arg fsX76)410cell lymphoma (BIA-ALCL), which is a rare form of T-cell lymphoma that occurs in some people who have had breast implants. BIA-ALCL in LFS has been accumulating and also requires atten-tion17). In this case, reconstruction was performed using a smooth type of implant, but there is a report recommending removal in cases of LFS using implants with textured surfaces. BIA-AL-CL-derived cell line studies have shown evidence of dysregulation of p53 signaling pathways in response to DNA damage18). Therefore, it is possible that BIA-ALCL develops due to inadequate tumor-suppressor activity in LFS.Characteristics of the variant in this caseIn LFS, missense variants account for about 70% of cases, and the variant in this case is a frameshift variant that has been reported in three cases, two of them developed osteosarcoma, breast cancer and no evidence of onset in childhood (Table 3)19, 20). Genotype-phenotype correlation has been reported for the TP53 gene, and variable phenotypes, expres-sivity, and penetrance of cancer are frequent21). Recently, variants leading to loss of function of p53 have been reported to have a more severe pheno-type than patients with partial loss22). The loss-of-function form has an early onset of primary cancer, often developing sarcoma or breast cancer by the Radiation therapySurgical therapySystemic drug therapyDiagnostic ImagingMRI, magnetic resonance imaging; RT, radiation therapy.Medical HistoryFamily historyF, female; M, male; Lt, left; Rt, right; y, years old; Pt, patient.RT of the intact breast is contraindicated.Postmastectomy RT should only be considered in patients with a significant risk of locoregional regional recurrence.〔Strength of recommendation: Moderate, Quality of evidence: Low (case-series only)〕A mastectomy is the recommended therapeutic option.Avoid cytotoxic anticancer drugs that induce DNA damage if possible.PARP inhibitors: insufficient evidence for moderately penetrant genes including TP53.Avoid radiation exposure (e.g.: ultrasound, MRI).Togucihda et al 199215yF OsteosarcomaMother: 25y Breast cancerZerdoumi Y et al 2017Pt22, 27yF Breast cancerPt21, 28yM UnaffectedNot listedage of 35 and meeting the classical LFS and Chom-pret’s criteria. The pathological variant in this case has also been reported to show normal p53 protein loss of function. In this case, the frameshift muta-tion has altered the structure of the p53 protein itself, so it is not detected by immunostaining. The possibility of a paternal origin has not been completely ruled out, since the LFS has a 75% male penetrance and the paternal uncle is also suspected of having skin cancer. However, since the proba-bility suggests that our case could be a single case, it is necessary to consider the possibility of germ-line mosaicism, which occurs at a frequency of 2.4% in addition to de novo8).Establishing a continuous surveillance systemA lifetime risk of developing cancer, and regular systemic screening is considered important in LFS. Currently, surveillance based on the Toronto protocol has been introduced worldwide for TP53 carriers (Table 4)13). Meanwhile since there are some differences in surveillance subjects and the timing of the start of surveillance subject depending on the region, it is better to refer to the guideline by Kumamoto et al. in Japan10). It is not clear whether the current surveillance studies contribute to improved survival rates due to the short obser-vation period and the low incidence of the disease. Our case 202116yF Osteosarcoma29y Lt-breast cancer33y Rt-breast cancerNot specific