Use of EUS-Guided Needle-Based Confocal Laser Endomicroscopy and Microforceps Biopsy to Prevent an Unnecessary Cyst-Gastrostomy

Abstract

Introduction: Current radiologic and endoscopic studies for pancreatic cystic lesions have known poor sensitivity and accuracy for distinguishing any particular cystic lesion. The current case describes the use of two novel EUS-guided tools for the diagnosis and management of a large, symptomatic pancreatic cyst. Case Description: 30 year old female with prior history of pancreatitis presented with left upper quadrant abdominal pain. MRCP revealed a large 28 mm x 39 mm unilocular cyst in the tail of the pancreas. Based on the history, the possibility of a pancreatic pseudocyst was raised. However, given the patient's young age and female gender, as well as the cyst morphology and location, a clinical suspicion was raised for a possible mucinous cystic neoplasm (MCN). Given the diagnostic uncertainty, and the vast differences in management of these lesions, the decision was made to perform further diagnostic testing to help guide management. EUS evaluation with multimodality sampling was performed. nCLE imaging revealed multiple thickened epithelial bands lining the cyst wall. Four biopsies were then obtained using the MFB. Following this, FNA was performed. Seventeen ml of dark brown watery fluid was obtained. Cyst fluid analysis demonstrated glucose 1,500 ng/ml, amylase 11,859 u/L. Cytology revealed foamy macrophages and a few clusters of bland glandular cells. MFB pathology yielded tissue with ovarian-like stroma with mucinproducing epithelial lining consistent with an MCN. The patient was referred for a distal pancreatectomy. Final surgical pathology revealed the cyst wall to be lined by flat cuboidal epithelium and ovarian-type stroma without cytologic atypia, papillary architecture or epithelial proliferation. Final diagnosis favored an endometrial cyst of the pancreas over an atypical MCN. The patient had resolution of her symptoms following surgery. Discussion: Standard EUS-FNA and cyst fluid analysis are suboptimal in their ability to make a cytopathologic diagnosis of a pancreatic cyst. In the current case, standard biochemical fluid analysis produced conflicting results showing both an elevated cyst fluid CEA and amylase, and thus unable to distinguish an inflammatory pseudocyst from a neoplastic or non-inflammatory cystic lesion. Cyst fluid cytology was similarly non-diagnostic. However, the combined use of EUS-guided nCLE and MFB produced highly detailed diagnostic information allowing for appropriate management. Watch the video: https://goo.gl/XkPkfy