Preoperative Treatment With FOLFIRINOX and Successful Resection for a Patient With Mixed Acinar-Endocrine Carcinoma of the Pancreas
Mixed acinar-endocrine carcinoma (MAEC) of the pancreas is an extremely rare entity. Therefore, the biological behavior of the MAEC of the pancreas has not been clearly determined and is generally considered as clinically aggressive. We report a case of a 48-year-old man with MAEC who underwent pancreaticoduodenectomy after neoadjuvant chemotherapy.
A 48-year-old man was referred to our institution for a large mass within the head of the pancreas. He was in his usual state of health until he developed severe abdominal pain a few weeks before presentation. A pancreas-protocol, contrast-enhanced CT showed a 7.7 × 5.9-cm enhancing solid mass with cystic portions in the pancreatic head and uncinate process (Fig. 1A). On the CT, the mass abutted the superior mesenteric vein (SMV) without narrowing it and also appeared to abut the posterior aspect of the superior mesenteric artery (SMA) (Fig. 1B). The patient underwent endoscopic ultrasonography (EUS) with fine-needle aspiration (FNA) of the mass. This revealed a malignant epithelioid neoplasm with both acinar and endocrine features. Immunohistochemical staining of the tumor cells showed strong positivity for trypsin and synaptophysin. The Ki-67 labeling index was 10% to 20%. No distant metastasis or lymphadenopathy was suggested on either the CT or EUS. Serum carbohydrate antigen 19–9 (CA 19–9) level was 374 U/mL.
Given the size and potential vascular involvement of the tumor, the patient received 6 cycles of FOLFIRINOX without any adverse effects. On the follow-up CT, the tumor showed a significant decrease in size to 1.9 × 1.4 cm (Fig. 1C). The tumor appeared to have retracted away from the SMV (Fig. 1D). There was still some soft tissue density on the CT scan involving the posterior aspect of the SMA; however, no evidence of metastatic disease or lymphadenopathy was seen. His serum CA 19–9 level had decreased to 29 U/mL. Since downstaging of the tumor was confirmed at this point, he underwent exploratory laparotomy and a pylorus-preserving pancreaticoduodenectomy. No vascular resection was required. The patient recovered uneventfully and was discharged on postoperative day 6.
Pathological examination with immunohistochemistry of the surgical specimen was consistent with MAEC of the pancreas(Fig. 2A–D): it was diffusely positive for trypsin and synaptophysin. The gross tumor size was 2.0 cm. The tumor cells invaded the retroperitoneal soft tissue. Margins were negative. No metastasis was detected within 34 harvested lymph nodes. Neither perineural invasion nor lymphovascular invasion were observed. Mild treatment response was seen. At the last follow-up, the patient was alive 21 months later without any evidence of recurrence.