Breast cancer with an intraductal component that was proven genetically to be metastasis of contralateral breast cancer: a case report

Yoshiaki Shinden,Yuki Nomoto,Akihiro Nakajo,Koji Minami,Tsubasa Hiraki,Tetsuhiro Owaki,Shoji Natsugoe,Toshiaki Akahane,Yuko Kijima,Ayako Nagata,Akihide Tanimoto,Hazuki Saho

doi:10.1186/s40792-020-00966-y

Yoshiaki Shinden, Yuki Nomoto + Show 10 more

Open Access

https://doi.org/10.1186/s40792-020-00966-y

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Abstract

BackgroundWhen diagnosing patients with bilateral breast cancer, it is challenging to determine the relationship between multiple breast cancer lesions at the individual patient level with certainty.Case presentationA 35-year-old Japanese woman was diagnosed with a left breast cancer. She was previously diagnosed with right pT3N3M0 stage IIIC breast cancer and underwent chemotherapy with targeted therapy, radiotherapy, and endocrine therapy as adjuvant treatment after mastectomy and axillary lymph node dissection. Approximately 2 years after the first surgery, her left breast cancer was preoperatively diagnosed as a contralateral primary breast cancer, and left mastectomy and axillary lymph node dissection were performed. Histopathologically, the tumor was determined to be invasive ductal carcinoma accompanied with several intraductal components. After a second surgery, mutation analysis of her bilateral breast cancer was performed in a clinical study, which revealed that her metachronous bilateral breast tumors had the same GATA3 and CSMD1 mutations. Thus, mutation analysis strongly supported her latter left breast cancer being a metastatic lesion from the former right breast cancer. Some difficulties in diagnosing bilateral breast cancer exist when determining whether they are double primary cancers or represent contralateral breast metastasis. The existence of intraductal components is a critical piece of information for suspecting primary lesions. However, this case demonstrated that metastatic contralateral breast lesions can have intraductal components.ConclusionHerein we report a genetically proven contralateral breast metastasis with some intraductal components.

Highlights

When diagnosing patients with bilateral breast cancer, it is challenging to determine the relationship between multiple breast cancer lesions at the individual patient level with certainty.Case presentation: A 35-year-old Japanese woman was diagnosed with a left breast cancer
Several diagnostic criteria exist for bilateral breast cancer, but it is challenging to determine the relationship between multiple breast cancer lesions at the individual patient level with certainty [6]
Using germline mutation analysis with the blood sample as a reference, only somatic mutations in tumor samples were analyzed using a web portal. This analysis revealed that her metachronous bilateral breast tumors had the same GATA binding protein 3 (GATA3) and CUB and Sushi multiple domains 1 (CSMD1) mutations (Table 1). These results strongly suggested that her latter left breast cancer was a metastatic lesion from the former right breast cancer

Summary

Background

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in females worldwide [1]. We report a case of metachronous bilateral breast cancer in whom the second breast cancer was diagnosed as a metastatic lesion from contralateral breast cancer using mutation analysis. This analysis revealed that her metachronous bilateral breast tumors had the same GATA3 and CSMD1 mutations (Table 1) These results strongly suggested that her latter left breast cancer was a metastatic lesion from the former right breast cancer. The left lesion had a different PgR status, was located in the outer upper region of the breast and far from the midline, and was not accompanied by distant metastatic lesions We diagnosed the latter breast cancer as a second primary lesion, because we detected in situ carcinoma contiguous to the invasive carcinoma in this lesion.

Conclusion

Funding None