BRCA1/BRCA2 Double Heterozygosity Presenting as Intrahepatic Cholangiocarcinoma

Abstract

We report a case of BRCA1/BRCA2 double heterozygosity-a rare condition with an estimated prevalence of fewer than 1 in 100,000 individuals in unselected populations-identified through tumor genomic profiling in a 50-year-old Japanese woman with intrahepatic cholangiocarcinoma and no prior cancer history. Germline testing confirmed BRCA1 c.2389_2390del and BRCA2 c.5621_5624del. This case demonstrates that intrahepatic cholangiocarcinoma can be a sentinel malignancy of BRCA-related cancer predisposition, thus underscoring the importance of germline testing.

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BibTeX RIS

BibTeX

@article{inagaki2026brca1brca2,
  title = {{BRCA1/BRCA2 Double Heterozygosity Presenting as Intrahepatic Cholangiocarcinoma}},
  author = {Natsuko Inagaki and Yoshiya Yamauchi and Sawako Matsumoto and Sakiko Naito and Masato Bingo and Hourin Cho and Yuri Ueda and Jingyi Dong and Kazuyo Kiribayashi and Akiko Yamamoto and Aoi Sukeda and Toshitaka Nagao and Takashi Ishikawa and Atsushi Sofuni and Takao Itoi},
  journal = {Internal Medicine},
  year = {2026},
  month = sep,
  doi = {10.2169/internalmedicine.7739-26},
  url = {https://www.jstage.jst.go.jp/article/internalmedicine/advpub/0/advpub_7739-26/_article},
  note = {CC BY-NC-ND},
}

RIS

TY  - JOUR
TI  - BRCA1/BRCA2 Double Heterozygosity Presenting as Intrahepatic Cholangiocarcinoma
AU  - Natsuko Inagaki
AU  - Yoshiya Yamauchi
AU  - Sawako Matsumoto
AU  - Sakiko Naito
AU  - Masato Bingo
AU  - Hourin Cho
AU  - Yuri Ueda
AU  - Jingyi Dong
AU  - Kazuyo Kiribayashi
AU  - Akiko Yamamoto
AU  - Aoi Sukeda
AU  - Toshitaka Nagao
AU  - Takashi Ishikawa
AU  - Atsushi Sofuni
AU  - Takao Itoi
PY  - 2026
DA  - 2026/09/22
JO  - Internal Medicine
DO  - 10.2169/internalmedicine.7739-26
UR  - https://www.jstage.jst.go.jp/article/internalmedicine/advpub/0/advpub_7739-26/_article
AB  - We report a case of BRCA1/BRCA2 double heterozygosity-a rare condition with an estimated prevalence of fewer than 1 in 100,000 individuals in unselected populations-identified through tumor genomic profiling in a 50-year-old Japanese woman with intrahepatic cholangiocarcinoma and no prior cancer history. Germline testing confirmed BRCA1 c.2389_2390del and BRCA2 c.5621_5624del. This case demonstrates that intrahepatic cholangiocarcinoma can be a sentinel malignancy of BRCA-related cancer predisposition, thus underscoring the importance of germline testing.
SN  - 1349-7235
SN  - 0918-2918
ER  -

Abstract

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