1252 Isolated Brain Metastasis From Pancreatic Cancer in Lynch Syndrome

Abstract

INTRODUCTION: Pancreatic cancer is the 4th leading cause of death in US. The incidence of pancreatic cancer metastasis to brain is rare ranging from 0.1 to 0.3% from various studies. Overall from our knowledge, this is the 26th reported case. This is the first reported case of a patient with a history of Lynch syndrome (LS) who was diagnosed with solitary brain metastasis from pancreatic adenocarcinoma and subsequently treated. CASE DESCRIPTION/METHODS: A 69-year-old female with history of LS and sarcoidosis presented complaining of new onset acute expressive aphasia. Patient's oncologic history significant for colon cancer status post (s/p) subtotal colectomy in 2007, pancreatic adenocarcinoma s/p Whipple in 4/2015. The pathology demonstrated isolated tumor cells in two peripancreatic lymph nodes treated with adjuvant gemcitabine. She had surveillance imaging in 9/2017 showing new metastatic disease, PET-avid retroperitoneal lymphadenopathy and cervical lymphadenopathy. Biopsy showed adenocarcinoma of pancreatic origin. She began gemcitabine/abraxane in 10/2017 with complete resolution on interval imaging in 1/2018. She continued chemotherapy with no metastatic disease on surveillance imaging and was well until presenting with aphasia in 2/2019. MRI of the brain revealed 2 cm enhancing left frontal lobe mass with vasogenic edema and 3 mm midline shift. Labwork including Ca 19-9 and CEA were normal. Because of the uncertainty of the origin of the metastatic disease, left frontal craniotomy and tumor resection was performed. Pathology demonstrated IHC positive for CK7, CK19, CA19-9, CDX-2, and negative for TTF-1, CK20, compatible with metastatic pancreatic adenocarcinoma. Subsequently, the patient underwent single fraction 20 Gy of CyberKnife radiosurgery. The patient symptoms improved and surveillance MRI in 6/2019 demonstrated decreased enhancement consistent with response to treatment. DISCUSSION: To our knowledge this is the first documented case of isolated brain metastatic from pancreatic adenocarcinoma in a LS patient. This case suggests awareness and brain imaging are necessary when pancreatic cancer patients present for neurological complaints. LS is due to germline mutations, which has a different pathogenesis from usual sporadic pancreatic adenocarcinoma. This may explain the unusual presentation, excellent response to therapy, and prolonged survival. Treatment with surgical resection and stereotactic radiosurgery can be considered.