A 56-year-old man presented to our hospital for close examination of a mass in the portal vein. CT showed a homogeneously enhanced mass occupying the portal vein. No other lesions suggestive of a primary
tumor were detected. Endoscopic ultrasound-guided fine-needle aspiration revealed that the
tumor was pathologically
acinar cell carcinoma (ACC) based on the positive staining for both BCL-10 and
trypsin. He was diagnosed with an ectopic ACC developed in the portal vein. Because the
tumor invaded secondary branches of the right intrahepatic portal vein and the superior mesenteric vein, it was considered surgically un-resectable. Therefore,
chemotherapy with gemcitabine plus
nab-paclitaxel (GEM + nab-PTX) was started. After 2 courses, CT showed progressive disease, so the regimen was switched to
FOLFIRINOX. After starting treatment with
FOLFIRINOX, the
tumor shrank gradually. After 29 courses, CT scan eventually showed disappearance of the
tumor and complete response was achieved. After 34 courses, the
chemotherapy was discontinued. Since then, the patient has been recurrence-free for 5 years. Our English literature review yielded 6 cases, including this case, of un-resectable ACC in which complete response was achieved by
chemotherapy. Our case suggest that
platinum-based regimen might be an effective
therapy for un-resectable ACC, including ectopic ACC.