浸潤性膵管腺癌切除標本に既知乳癌由来の腹部リンパ節転移を認めた

Incidental abdominal lymph node metastases from a known breast cancer in resected specimen of invasive pancreatic ductal adenocarcinoma: report of a case.

• Tomohiko Taniai
• Koichiro Haruki
• Michinori Matsumoto
• Taro Sakamoto
• Hiroaki Shiba
• Katsuhiko Yanaga

抄録

乳がんは全身のあらゆる臓器に転移することが知られています。しかし、乳癌からの腹部リンパ節転移は極めて稀である。本稿では、乳癌からの腹部リンパ節転移と診断された浸潤性膵管腺癌（PDAC）の切除例を報告する。54歳女性は膵尾部に腫瘍があり，遠位膵管拡張を伴うと指摘された．51歳で左乳癌で乳房部分切除術を受け，6ヶ月前に肝転移で肝臓部分切除術を受けていた．CT検査では膵尾部に低密度の腫瘍が認められ，主膵管が拡張していた．磁気共鳴画像法（MRI）では、拡散強調画像で膵尾部に高強度の腫瘍が認められた。膵臓癌と診断され，遠位膵切除術とリンパ節郭清を伴う脾臓切除術を施行した．脾動脈に沿ったリンパ節転移はPDACと病理学的に類似していた。しかし、左胃動脈、総肝動脈、腹腔軸、上腸間膜動脈に沿ったリンパ節転移は病理学的には乳癌と類似していた。腹部リンパ節の免疫組織化学染色ではGATA-3が陽性であり、転移性乳癌を強く示唆していた。乳癌に対してS-1とPDACによる化学療法を4ヶ月間受けたが，MRIでは乳癌由来の多発性肝転移が認められ，12ヶ月後に死去した．最終的に術後12ヶ月で死亡した。

Breast cancer is known to metastasize to all organs of the body. However, abdominal lymph node metastases from breast cancer are extremely rare. We herein report a resected case of an invasive pancreatic ductal adenocarcinoma (PDAC) in which abdominal lymph node metastases from breast cancer were diagnosed. A 54-year-old woman was pointed out to have a tumor in the pancreatic tail with dilatation of the distal pancreatic duct. She had undergone partial mastectomy for left breast cancer at the age of 51 years and had undergone partial liver resection for liver metastasis in the segment 3/4 6 months earlier. Computed tomography revealed a low-density tumor in the pancreatic tail with dilated distal main pancreatic duct. Magnetic resonance imaging (MRI) exhibited a high-intensity tumor in the pancreatic tail in diffusion-weighted images. With a diagnosis of pancreatic cancer, distal pancreatectomy and splenectomy with lymph nodes dissection was performed. Lymph node metastases along the splenic artery were pathologically similar to PDAC. However, lymph node metastases along the left gastric artery, common hepatic artery, celiac axis, and superior mesenteric artery were pathologically similar to breast cancer. Immunohistochemistry staining of abdominal lymph nodes with GATA-3 was positive, which strongly suggested metastatic breast cancer. Although she received chemotherapy with S-1 for breast cancer and PDAC for 4 months, MRI showed multiple liver metastases derived from breast cancer. Finally, she died 12 months after operation.