Endoscopic Ultrasound Features Associated with Malignancy and Aggressiveness of Nonhypovascular Solid Pancreatic Lesions: Results from a Prospective Observational Study

Abstract

Background and Study Aims On contrast-enhanced imaging studies, nonhypovascular (i. e., isovascular and hypervascular) patterns can be observed in solid pancreatic lesions (SPLs) of different nature, prognosis, and management. We aimed to identify endoscopic ultrasound (EUS) features of nonhypovascular SPLs associated with malignancy/aggressiveness. The secondary aims were EUS tissue acquisition (EUS-TA) outcome and safety in this setting of patients. Patients and Methods This prospective observational study included patients with nonhypovascular SPLs detected on cross-sectional imaging and referred for EUS-TA. Lesion features (size, site, margins, echotexture, vascular pattern, and upstream dilation of the main pancreatic duct) were recorded. Malignancy/aggressiveness was determined by evidence of carcinoma at biopsy/surgical pathology, signs of aggressiveness (perineural invasion, lymphovascular invasion, and/or microscopic tumor extension/infiltration or evidence of metastatic lymph nodes) in the surgical specimen, radiologic detection of lymph nodes or distant metastases, and/or tumor growth > 5 mm/6 months. Uni- and multivariate analyses were performed to assess the primary aim. Results A total of 154 patients with 161 SPLs were enrolled. 40 (24.8 %) lesions were defined as malignant/aggressive. Irregular margins and size > 20 mm were independent factors associated with malignancy/aggressiveness (p < 0.001, OR = 5.2 and p = 0.003, OR = 2.1, respectively). However, size > 20 mm was not significant in the subgroup of other-than-neuroendocrine tumor (NET) lesions. The EUS-TA accuracy was 92 %, and the rate of adverse events was 4 %. Conclusion Irregular margins on EUS are associated with malignancy/aggressiveness of nonhypovascular SPLs. Size > 20 mm should be considered a malignancy-related feature only in NET patients. EUS-TA is safe and highly accurate for differential diagnosis in this group of patients.

Improved diagnostic yield of endoscopic ultrasound-fine needle biopsy with histology specimen processing

“…Recent studies have suggested alternate methods to increase diagnostic yield. In particular, contrast-enhanced EUS could be of significant benefit in characterizing pancreatic lesions[ 6 ], and touch-imprint cytology allows for processing of a single specimen for both cytology and histology[ 26 ].…”

“…However, several factors can limit the sensitivity of EUS-FNA. EUS-FNA samples are typically processed as cytology, which does not allow for preservation of tissue architecture necessary for diagnosis of diseases such as gastrointestinal stromal tumor (GIST)[ 3 ], lymphoma[ 4 ], autoimmune pancreatitis[ 5 ], and pancreatic lesions with non-hypovascular contrast-enhancement pattern on EUS[ 6 ]. The diagnostic yield of EUS-FNA may be further compromised by the limited availability of on-site cytopathologists[ 7 - 11 ].…”

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

“…The tip of the instrument is covered with a water-filled balloon allowing adequate transmission of ultrasound to improve image quality. A view of the whole pancreas is then taken according to the standard method of execution including a description of tumor location, size, margins (smooth or irregular), assessment of the echogenicity, distance from main pancreatic duct (MPD), evidence of upstream MPD dilatation, and vascular involvement [33,43]. PanNENs typically appear as hypoechoic, well-demarcated, round, hypervascular, homogeneous internal echo pattern lesions.…”

“…The majority of PanNENs are solid lesions but less commonly may also appear as cystic [12,32,33,45]. However, lesions with diameter >2 cm, irregular margins, heterogeneous echotexture, and upstream dilation of the MPD are significantly associated with malignancy/aggressiveness completely indistinguishable from the most common adenocarcinoma [12,43,44]. In addition, because some patients may present multiple PanNENs, (MEN in 36% to 81%) [42] it is important to examine the entire pancreas to exclude synchronous lesions, and if present, awareness of suspicious features may help the endosonographer to choose the lesion to be punctured, [12,32,33,42].…”

Endoscopic Ultrasound Fine-Needle Biopsy versus Fine-Needle Aspiration for Tissue Sampling of Abdominal Lymph Nodes: A Propensity Score Matched Multicenter Comparative Study

“…Endosonographic characteristics of malignant lymph nodes include a large size, hypoechogenicity, distinct border, round shape, and high tissue stiffness on elastography [ 3 , 4 ]. Unfortunately, simple LN morphology assessed through EUS is not sufficient to definitively distinguish benign nodes from malignant ones, thus an appropriate tissue sampling-aimed technique with concomitant pathological confirmation is often employed [ 5 , 6 ].…”