Successful pancreatectomy after conversion-intended chemotherapy using gemcitabine and nab-paclitaxel for unresectable adenosquamous carcinoma of the pancreas: a case report

Abstract

Background: Adenosquamous carcinoma of the pancreas (ASCP) accounts for only 1-4% of all pancreatic exocrine cancers and has a particularly poor prognosis. The efficacy of chemotherapy for ASCP remains unknown because of the small number of cases, and few studies have evaluated conversion-intended chemotherapy.

Case presentation: A 76-year-old woman was referred to our hospital because of epigastric pain and nausea. A preoperative contrast-enhanced multidetector row computed tomography (MDCT) scan revealed a 17 × 17 mm low-density tumor with an ill-defined margin at the arterial phase in the pancreatic head. The tumor involved the common hepatic artery, left hepatic artery bifurcated from the common hepatic artery, and gastroduodenal artery, and was in contact with the portal vein. Fluorodeoxyglucose-positron emission tomography (FDG-PET) showed an uptake in the pancreatic head but no evidence of distant metastasis. The tumor was diagnosed as an adenocarcinoma of the pancreatic head and staged unresectable because the common and left hepatic arteries were involved. Hence, the patient underwent seven courses of conversion-intended chemotherapy using gemcitabine and nab-paclitaxel for pancreatic ductal adenocarcinoma over 7 months. After chemotherapy, the tumor shrank to 10 × 10 mm on contrast-enhanced MDCT. Consequently, the boundary between the tumor and major vessels of the common and left hepatic arteries and the portal vein became clear, and the involvement of the arteries with the tumor was evaluated to be released. The contact of the tumor to the portal vein also reduced to less than half the circumference of the portal vein. FDG-PET showed decreased accumulation in the tumor. Hence, the tumor was judged resectable, and pancreaticoduodenectomy was performed. The tumor and major blood vessels were easily dissected and R0 resection was achieved. The patient experienced no major complications and was discharged on postoperative day 28. The tumor was revealed as ASCP via pathological examination. The patient is alive and recurrence-free seven months after surgery. This is the first report of successful R0 resection for an initially unresectable ASCP following conversion-intended chemotherapy using gemcitabine and nab-paclitaxel regimen.

Conclusions: Conversion-intended chemotherapy using gemcitabine and nab-paclitaxel regimen may be effective for ASCP.

Keywords: Carcinoma, Adenosquamous; Chemotherapy; Neoadjuvant therapies; Pancreatic cancer.

Fig. 1

Multidetector row computed tomography (MDCT) scan findings of a pancreatic adenosquamous carcinoma. a–c Contrast-enhanced MDCT scan findings before conversion-intended chemotherapy. The tumor had invaded the common and left hepatic arteries and contacted more than half the circumference of the portal vein. d–f Contrast-enhanced MDCT scan findings after conversion-intended chemotherapy. The tumor in the pancreatic head shrank to release the involvement of the common hepatic and left hepatic artery. The contact with the tumor to the portal vein became less than half the circumference of this vein. T, tumor; CHA, common hepatic artery; SPA, splenic artery; PV, portal vein; LHA, left hepatic artery; SPV, splenic vein; and SMV, superior mesenteric vein

Fig. 2

Multidetector row computed tomography (MDCT) scans of a pancreatic adenosquamous carcinoma. a, b Contrast-enhanced MDCT scans before conversion-intended chemotherapy. The tumor had invaded the common hepatic, left hepatic, and gastroduodenal arteries and contacted the superior mesenteric and portal veins. c, d Contrast-enhanced MDCT scans after conversion-intended chemotherapy. The margin of the common and left hepatic arteries became distinct, and clear fat planes around these arteries were observed. GDA, gastroduodenal artery

Fig. 3

Fluorodeoxyglucose-positron emission tomography (FDG-PET) findings. a, b Before neoadjuvant chemotherapy, FDG-PET showed a standardized uptake maximum value of 6.6 in the pancreatic head. c, d After chemotherapy, FDG-PET showed a decreased accumulation with a standardized uptake maximum of 3.6 in the tumor

Fig. 4

Intraoperative findings. a The tumor did not invade the common or left hepatic arteries and was easily dissected. b The tumor in the pancreatic head did not invade the portal vein and could be dissected without resection of the portal vein. c The right hepatic artery was bifurcated from the celiac artery and showed no tumor invasion. d The tumor did not invade the superior mesenteric artery. Finally, R0 resection was performed. 1. Left hepatic artery, 2. common hepatic artery, 3. gastroduodenal artery, 4. pancreas head, 5. right hepatic artery, and 6. superior mesenteric artery

Fig. 5

Histological and immunohistochemical results of adenosquamous carcinoma of the pancreas. Hematoxylin and eosin staining (a, 20 ×) and (b, 200 ×) revealed the adenocarcinoma component forming glandular structures and the squamous cell carcinoma component displaying nests, which were partially intermingled with continuity. Black arrow: adenocarcinoma; white arrow: squamous cell carcinoma. c Immunohistochemical p40 staining is positive for squamous cell carcinoma and negative for adenocarcinoma. d CK7 staining is positive for adenocarcinoma and negative for squamous cell carcinoma