Splenic Branch Intraductal Papillary Mucinous Neoplasm (IPMN) diagnosis?

From the Guidelines

Diagnosis of Splenic Branch Intraductal Papillary Mucinous Neoplasm (IPMN) is based on a combination of imaging and histopathological examination.

Key Diagnostic Features

• The diagnosis of IPMN involves the evaluation of the degree of dysplasia and the presence or absence of an associated invasive carcinoma 1.
• Imaging modalities such as high-resolution CT, endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP) are used to evaluate the pancreatic cysts and ductal dilatation 1.
• The Sendai guidelines recommend resection of main pancreatic duct IPMNs, side branch duct IPMNs measuring >3 cm, those with nodules in the cystic wall, and those that cause symptoms 1.

Histopathological Examination

• The histopathological examination of the entire specimen is crucial to exclude the presence of an invasive component 1.
• The Verona consensus meeting recommends extensive sampling to rule out invasive carcinoma, and documentation of the invasive component, including its size, type, grade, and stage 1.
• The highest grade of dysplasia in the non-invasive component should be documented separately, and the lesion size should be correlated with imaging findings 1.

Subtyping of IPMNs

• IPMNs can be subtyped into gastric, intestinal, pancreatobiliary, oncocytic, and mixed types, based on their cell lineage and morphology 1.
• Each subtype has distinct clinicopathologic associations, cancer progression rates, immunophenotype, and molecular characteristics 1.

Reporting Principles

• The reporting principles for IPMN are also applicable to other tumoral intraepithelial neoplasms of the pancreatobiliary tract, including mucinous cystic neoplasms, intraductal tubular/tubulopapillary neoplasms, and intracholecystic papillary tubular neoplasms 1.
• The grading scheme and terminology for these tumors are mostly adopted from those used for IPMNs, and they can be associated with invasive carcinoma of various types 1.

From the Research

Diagnosis of Splenic Branch Intraductal Papillary Mucinous Neoplasm (IPMN)

• Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a noninvasive epithelial neoplasm of mucin-producing cells arising in the main duct and/or branch ducts of the pancreas 2.
• IPMN can be divided into main duct-IPMN (MD-IPMN), branch duct-IPMN (BD-IPMN), and mixed type-IPMN, with different biological differences and prognostic implications 2, 3, 4.
• Diagnosis of IPMN involves high-resolution imaging techniques, such as magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS), to identify ductal dilation, intraductal papillary growth, and thick mucus secretion 4, 5.
• The diagnosis of IPMN also involves the analysis of aspirated cystic fluid for cytology and DNA analysis, although the role of pancreatoscopy is still to be established 5.

Classification and Risk Stratification

• IPMNs are classified into low-grade, intermediate-grade, and high-grade dysplasia based on cytoarchitectural atypia, and into gastric, intestinal, pancreatobiliary, and oncocytic types based on histological features and mucin immunophenotype 2.
• The risk of malignancy varies from 57% to 92% in MD-IPMN and from 6% to 46% in BD-IPMN, with features such as obstructive jaundice, mass lesion, enhanced solid component, and main pancreatic duct size ≥10 mm considered high-risk malignant lesions 5.
• The Sendai International Association of Pancreatology guidelines, American Gastroenterological Association guidelines, revised international consensus Fukuoka guidelines, and European evidence-based guidelines provide recommendations for the diagnosis and management of IPMNs 4.

Management and Treatment

• Management of IPMN depends on the type and radiological features of IPMNs, with surgery recommended for MD-IPMN and mixed type-IPMN, and surveillance or surgery for BD-IPMN depending on tumor size, cyst growth rate, and other factors 4.
• Resection is recommended for most MD-IPMN, mixed variant, and symptomatic BD-IPMN, with 5-year survival rates reported to be 77-100% for noninvasive IPMN and 27-60% for invasive carcinoma 5.
• Follow-up of patients with IPMN can vary from 6 months to 1 year, depending on the risk stratification for invasive malignancy and the pathology of the resected specimen 5.