Pancreatic Cysts after Endoscopic Ultrasonography-Guided Ethanol and/or Paclitaxel Ablation Therapy: Another Mimic of Pancreatic Pseudocysts

Abstract

<b><i>Background:</i></b> Endoscopic ultrasound-guided ablation (EUS-A) therapy is a minimally invasive procedure for pancreatic-cystic tumors in patients with preoperative comorbidities or in patients who are not indicated for surgical resection. However, histopathologic characteristics of pancreatic cysts after ablation have not been well-elucidated. <b><i>Methods:</i></b> Here, we analyzed pathological findings of 12 surgically resected pancreatic cysts after EUS-A with ethanol and/or paclitaxel injection. <b><i>Results:</i></b> Mean patient age was 49.8 ± 13.6 years with a 0.3 male/female ratio. Clinical impression before EUS-A was predominantly mucinous cystic neoplasms. Mean cyst size before and after ablation therapy was similar (3.7 ± 1.0 cm vs. 3.4 ± 1.6 cm; <i>p</i> = 0.139). Median duration from EUS-A to surgical resection was 18 (range, 1–59) months. Mean percentage of the residual neoplastic lining epithelial cells were 23.1 ± 37.0%. Of the resected cysts, 8 cases (67%) showed no/minimal (<5%) residual lining epithelia, while the remaining 4 cases (33%) showed a wide range of residual mucinous epithelia (20–90%). Ovarian-type stroma was noted in 5 cases (42%). Other histologic features included histiocytic aggregation (67%), stromal hyalinization (67%), diffuse egg shell-like calcification along the cystic wall (58%), and fat necrosis (8%). <b><i>Conclusion:</i></b> Above all, diffuse egg shell-like calcification along the pancreatic cystic walls with residual lining epithelia and/or ovarian-type stroma were characteristics of pancreatic cysts after EUS-A. Therefore, understanding these histologic features will be helpful for precise pathological diagnosis of pancreatic cystic tumor after EUS-A, even without knowing the patient’s history of EUS-A.

Performance and Safety of EUS Ablation Techniques for Pancreatic Cystic Lesions: A Systematic Review and Meta-Analysis

“…Moreover, from the 36 recorded severe adverse events, 31 (86.1%) occurred after ethanol or ethanol/paclitaxel ablation. In addition to the reported complications, chemoablation was reported as associated with the development of new cysts, similar to pseudocysts, with specific radiological and histological characteristics [43]. Choi et al [42] in their patient cohort treated with ethanol, indicated that SB-IPMNs, multilocular cysts, suspected ethanol leakage during the procedure, and increased cystic fluid viscosity were independently associated with pancreatitis, however their conclusions were not confirmed by other reports.…”

The effect of different drugs on the ablation of subcutaneous insulinoma in nude mice

“…In recent years, the "ethanol-free" ablation technique has been proven to be safer and more effective in certain hepatic and pancreatic cystic lesions. It has also demonstrated the ability to reduce the incidence of adverse reactions [20][21][22][23] . Building upon previous studies, our hypothesis was that "alcohol-free" ablation could be equally applicable to solid tumors of the pancreas.…”

Endoscopic Ultrasound-Guided Local Ablative Therapies for the Treatment of Pancreatic Neuroendocrine Tumors and Cystic Lesions: A Review of the Current Literature

“…While these prior studies sought to measure the efficacy and durability of EUSguided intratumoral drug delivery based on post-procedural radiographic cyst resolution, An et al [65] recently reported the histopathologic characteristics of 12 surgically resected PCNs following EUS-guided local ablation with ethanol and/or paclitaxel. Based on pretreatment imaging, a majority (84%) of these lesions were believed to be MCNs, with a mean cyst size that was similar pre-and post-procedure.…”