Use of needle-based confocal laser endomicroscopy in the diagnosis of multifocal intraductal papillary mucinous neoplasm with high grade dysplasia

A 64-year-old woman with newly diagnosed type 2 diabetes mellitus was admitted with intermittent abdominal pain of 3 years’ duration. Computed tomography (CT) showed multifocal pancreatic cystic lesions with a dilated main pancreatic duct and calcification of a cyst wall ([Fig. 1]), raising suspicion of a mucinous neoplasm of the pancreas.

Fig. 1 Computed tomography (CT) image showing multifocal pancreatic cystic lesions with dilated main pancreatic duct (black arrow) and calcification of cyst wall (white arrow). The patient was a 64-year-old woman with newly diagnosed type 2 diabetes mellitus and with intermittent abdominal pain of 3 years’ duration.

Needle-based confocal laser endomicroscopy (nCLE) (AQ-Flex 19; Mauna Kea Technologies, France) is a novel imaging technique that enables real time in vivo microscopic imaging of a cyst wall during endoscopy, with a promising diagnostic yield [1] [2] [3]. The diagnosis of intraductal papillary mucinous neoplasm (IPMN) is indicated by the presence of finger-like papillae, while mucinous cystic neoplasms (MCNs) have a characteristic single band-like epithelium on nCLE [1] [2] [3].

We performed endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in our patient, with EUS confirming multifocal anechoic cystic lesions extending from the head of the pancreas to the tail, with hyperechoic margins. nCLE showed dark aggregates of cells with surrounding small vessels ([Video 1]), which had indicated features concerning for neoplasia in an earlier study [4]. The cyst fluid had a mucinous appearance and viscosity, and FNA cytology confirmed neoplastic mucinous cells ([Fig. 2 a, b]). The patient consequently underwent a total pancreatectomy ([Fig. 3]). Histopathological examination revealed an IPMN with high grade dysplasia ([Fig. 4]). Lymph node sampling was negative for metastasis.

Video 1 Needle-based confocal laser endomicroscopy (nCLE) in the diagnosis of multifocal intraductal papillary mucinous neoplasm with high grade dysplasia: endoscopic ultrasound shows multifocal cystic lesions with hyperechoeic margins, and nCLE shows dark aggregates of cells with surrounding small vessels.

Fig. 2 a Fine needle aspiration (FNA) specimen showing mucinous appearance. b FNA cytology shows neoplastic mucinous cells (hematoxylin and eosin [H&E], × 200).

Fig. 3 The surgically resected specimen. Throughout the pancreas there were multifocal cystic lesions filled with mucus.

Fig. 4 Histopathological appearance shows papillae protruding into the cyst lumen and neoplastic mucinous cells arranged in an irregular multilamellar pattern without infiltration (hematoxylin and eosin [H&E], × 40).

Wider use of nCLE has resulted in consensus on some of the characteristic features of common pancreatic cystic lesions, but this is an evolving area with scope for further definition of diagnostic features. In this case, nCLE images showed features concerning for neoplasia prior to surgery. The pattern of dark aggregates of cells surrounded by small vessels may be a promising characteristic in identification of malignant pancreatic cystic lesions (MPCLs). Further studies are required to confirm these findings and to establish nCLE criteria in the diagnosis of MPCLs.

Endoscopy_UCTN_Code_CCL_1AF_2AF_3AC

• References

• 1 Nakai Y, Iwashita T, Park DH. et al. Diagnosis of pancreatic cysts: EUS guided, through-the-needle confocal laser-induced endomicroscopy and cystoscopy trial: DETECT study. Gastrointest Endosc 2015; 81: 1204-1214
• 2 Napoleon B, Lemaistre AI, Pujol B. et al. In vivo characterization of pancreatic cystic lesions by needle-based confocal laser endomicroscopy (nCLE): proposition of a comprehensive nCLE classification confirmed by an external retrospective evaluation. Surg Endosc 2016; 30: 2603-2612
• 3 Napoleon B, Lemaistre AI, Pujol B. et al. A novel approach to the diagnosis of pancreatic serous cystadenoma: needle-based confocal laser endomicroscopy. Endoscopy 2015; 47: 26-32
• 4 Konda VJ, Meining A, Jamil LH. et al. A pilot study of in vivo identification of pancreatic cystic neoplasms with needle-based confocal laser endomicroscopy under endosonographic guidance. Endoscopy 2013; 45: 1006-1013