[Solid pseudopapillary neoplasms of the pancreas : Diagnostics, surgical treatment and postoperative outcome]. / Solid-pseudopapilläre Neoplasien des Pankreas : Diagnostik, chirurgische Therapie und postoperatives Outcome.

BACKGROUND: Malignant solid pseudopapillary neoplasms (SPN) are rare tumor entities of the pancreas. The prognosis for SPN is generally excellent, although some tumors have malignant potential and tend to metastasize or relapse. OBJECTIVE: The aim was to investigate whether there are histopathological or surgical risk factors that enable the biological potential of SPN to be estimated. PATIENTS AND METHODS: Data from patients with SPN treated in two large German pancreas centers from 2009 to 2018 were evaluated with respect to the occurrence of SPN, surgical management, histopathological tumor characteristics and the postoperative outcome. RESULTS: A total of 22 patients with SPN (17 women, 5 men) were operated on. The median age of the patients was 37 years (range 19-69 years). At the time of surgery 20 patients showed tumor growth limited to the pancreas. A female patient with recurrence of an externally resected SPN had lymph node involvement. Another female patient had a hepatic metastatic recurrence (Union Internationale contre Cancer (UICC) stage IV) of an externally resected SPN. Although all patients survived recurrence-free during the follow-up, this patient developed liver metastases again. The survival rate up to the end of the follow-up (median 43 months; range 1-132 months) of this study was 100%. CONCLUSION: There is a lack of knowledge of the possible parameters that can be used to predict the biological behavior of SPN. Apart from an increased likelihood of recurrence after resection of an SPN recurrence, no clear risk factors could be identified in the examined patient collective that could indicate an increased malignant potential and a possibly poorer outcome. Only a radical surgical resection with lymphadenectomy enables a reliable assessment of the tumor stage and the removal of possibly affected lymph nodes, which could be the cause of a recurrence if left intact.

DOG1 is commonly expressed in pancreatic adenocarcinoma but unrelated to cancer aggressiveness.

BACKGROUND: DOG1 (ANO1; TMEM16A) is a voltage-gated calcium-activated chloride and bicarbonate channel. DOG1 is physiologically expressed in Cajal cells, where it plays an important role in regulating intestinal motility and its expression is a diagnostic hallmark of gastrointestinal stromal tumors (GIST). Data on a possible role of DOG1 in pancreatic cancer are rare and controversial. The aim of our study was to clarify the prevalence of DOG1 expression in pancreatic cancer and to study its association with parameters of cancer aggressiveness. METHODS: DOG1 expression was analyzed by immunohistochemistry in 599 pancreatic cancers in a tissue microarray format and in 12 cases of pancreatitis on large tissue sections. RESULTS: DOG1 expression was always absent in normal pancreas but a focal weak expression was seen in four of 12 cases of pancreatitis. DOG1 expression was, however, common in pancreatic cancer. Membranous and cytoplasmic DOG1 expression in tumor cells was highest in pancreatic ductal adenocarcinomas (61% of 444 interpretable cases), followed by cancers of the ampulla Vateri (43% of 51 interpretable cases), and absent in 6 acinus cell carcinomas. DOG1 expression in tumor associated stroma cells was seen in 76 of 444 (17%) pancreatic ductal adenocarcinomas and in seven of 51 (14%) cancers of the ampulla Vateri. Both tumoral and stromal DOG1 expression were unrelated to tumor stage, grade, lymph node and distant metastasis, mismatch repair protein deficiency and the density of CD8 positive cytotoxic T-lymphocytes in the subgroups of ductal adenocarcinomas and cancers of ampulla Vateri. Overall, the results of our study indicate that DOG1 may represent a potential biomarker for pancreatic cancer diagnosis and a putative therapeutic target in pancreatic cancer. However, DOG1 expression is unrelated to pancreatic cancer aggressiveness.