INTRODUCTION: Primitive neuroectodermal tumors (PNET) are highly aggressive malignancies composed of small round cells that are neuroectodermal in origin similar to Ewings Sarcoma. PNET of the pancreas is extremely rare with around 20 cases reported in literature.
CASE REPORT: A 60-year-old male experienced abdominal pain, appetite loss and weight loss of around 40 pounds for several months. Abdominal CT revealed a pancreatic head mass with a pseudocyst causing gastric outlet obstruction. He underwent an endoscopic ultrasound guided FNA which did not show any evidence of malignancy. An attempted endoscopic drainage of the pseudocyst was unsuccessful. An exploratory laparotomy with en bloc resection of multiple abdominal organs did not provide much benefit as the pseudocyt recurred, leading way for a second limited laparotomy. Pathology was consistent with PNET demonstrating Immunohistochemistry (IHI) positivity for FL1, CD99, Vimentin and synaptophysin and a Ki 67 index of 90%. 6 months into his course, he was hospitalized with sepsis which was believed to be secondary to peritonitis. CT abdomen showed multiple hepatic masses and extensive omental carcinomatosis with free fluid in the abdomen. The infection failed to improve with antibiotics and supportive care. His poor performance status meant systemic therapy or repeat surgery was not an option. It was believed that his worsening clinical status was due to his enormous intra-abdominal tumor burden. He eventually decided to become comfort care and proceed with hospice.
DISCUSSION: Histopathology, IHI and genetic analysis are essential in the diagnosis of PNET of the pancreas, as other pancreatic mesenchymal and neuroendocrine tumors, pancreatoblastomas and lymphomas are differentials. PNET generally express the MIC2 protein (CD99), vimentin and 85-95% of the times, have the translocation resulting in the EWS-FLI1 fusion product. Abdominal pain, jaundice, dyspepsia and vomiting are the usual presenting symptoms with the head of the pancreas being the most common location. Multi-agent regimes like cyclophosphamide, adriamycin, and vincristine or neoadjuvant vincristine, dactinomycin, adriamycin, cyclophosphamide, ifosfamide and etoposide have been used with limited success This can be combined with surgery and radiation, but the prognosis remains to be poor. Thus, more research is needed to better manage this morbid malignancy.