Clinical significance of pancreatic intraepithelial neoplasia in resectable pancreatic cancer on survivals

PURPOSE: Noninvasive precursor lesions for pancreatic adenocarcinoma include pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. PanIN is often found synchronously adjacent to resected pancreatic ductal adenocarcinoma (PDAC) tumors. However, its prognostic significance on outcome after PDAC resection is unknown. The purpose of the current study was to determine if the presence of PanIN has a prognostic or predictive effect on survival after resection for PDAC with curative intent. METHODS: We retrospectively reviewed the clinicopathologic data of patients who underwent pancreatectomy for PDAC from January 2002 to January 2013. Intraductal papillary mucinous lesions and mucinous cystic neoplasms were excluded. All available postoperative imaging and clinical follow-up data were reviewed. RESULTS: There were 95 patients who underwent pancreatectomy. Tumors were most commonly located in the pancreas head and as such pancreaticoduodenectomy was the most commonly performed operation. The median tumor size was 3.2 cm. An absence of PanIN lesions was identified in 39 patients (41%). Of the patients with PanIN lesions, high-grade PanIN (grade 3) was the most common type (64.3%) followed by grade 2 (28.6%). There was no significant difference in overall survival or disease-free survival between the non-PanIN and PanIN groups. CONCLUSION: The presence or absence of PanIN lesions did not affect survival in patients undergoing resection for pancreatic cancer. However, patients with high-grade PanINs tended to have better overall survival. Larger studies with longer follow up are needed to accurately determine its clinical significance.

Primitive Neuroectodermal Tumor on the Buttock

Primitive neuroectodermal tumors (PNET) usually arise in the brain and central nervous system, but rarely occur outside of the brain, such as in the limbs, pelvis, paravertebral region or chest wall. Herein, a case of PNET on the buttocks is reported. A 24-year-old female was admitted for evaluation of a mass on her left buttock. An incisional biopsy revealed a primitive neuroectodermal tumor, with focal neural differentiation histologically. Preoperative MRI demonstrated the tumor was located in the subcutaneous layer of the left perineum, and extended to the ischiorectal fossa. The lesion showed an irregular, but well defined border; however, the differentiation from the left posterior wall of anus was focally obliterated. On operation, the tumor was not adhered to the surrounding structure, except for the external anal sphincter. The mass was completely resected. The tumor was about 8 x 9 x 5.8 cm in size, and the pathological evaluation confirmed a PNET, with a free anal sphincter margin. Therefore, chemoradiation therapy was planned, but the tumor recurred two months later. It was recommended the patient undergo a re-resection, but was lost before the procedure could be undertaken.