In a 59-year-old woman with a 3.5 × 3.3 × 3.3 cm rim‑enhancing mass at the pancreatic neck‑body junction that is predominantly non‑enhancing centrally, shows a delayed‑enhancing thick capsule with wall nodularity, no other sites involved, normal tumor markers except an elevated CA‑125, and a normal transvaginal ultrasound, what is the next step in management?

EUS with FNA is the Next Step

This patient requires endoscopic ultrasound with fine needle aspiration (EUS-FNA) to characterize this concerning pancreatic lesion before determining definitive management. 1

Rationale for EUS-FNA

This 59-year-old woman presents with at least two high-risk features that mandate further tissue characterization:

• Size ≥3.5 cm (increases malignancy risk ~3-fold)
• Wall nodularity (solid component increases malignancy risk ~8-fold)
• Thick enhancing capsule with delayed enhancement pattern

The AGA guidelines explicitly state that pancreatic cysts with at least 2 high-risk features (size ≥3 cm, dilated main pancreatic duct, or solid component) should be examined with EUS-FNA 1. The European guidelines similarly recommend EUS-FNA when clinical or radiological features of concern are identified, as it improves diagnostic accuracy for differentiating mucinous versus non-mucinous lesions and benign versus malignant pathology 2.

What EUS-FNA Should Accomplish

During the procedure, the following should be obtained:

• Targeted cytology of the wall nodularity/solid component 2
• Cyst fluid analysis for:
  • CEA level (≥192 ng/mL suggests mucinous neoplasm)
  • Cytology
  • Consider KRAS/GNAS mutation analysis if available 2
• Contrast-enhanced harmonic EUS (CH-EUS) to better evaluate the mural nodules for hyperenhancement, which raises concern for malignant transformation 2

Critical Diagnostic Considerations

The imaging characteristics described—rim enhancement with central non-enhancement, thick capsule, and wall nodularity—create a broad differential that includes:

• Mucinous cystic neoplasm (MCN) with high-grade dysplasia or invasive component
• Solid pseudopapillary neoplasm (SPN) (particularly given patient demographics: middle-aged female) 3, 4, 5
• Cystic pancreatic neuroendocrine tumor (pNET) with cystic degeneration
• Intraductal papillary mucinous neoplasm (IPMN) with worrisome features

The elevated CA-125 with normal transvaginal ultrasound is a red herring—CA-125 can be elevated in pancreatic mucinous neoplasms and does not necessarily indicate ovarian pathology in this context.

Why Not Proceed Directly to Surgery?

While some clinicians might consider proceeding directly to surgical resection given the concerning features, EUS-FNA should be performed first because 2:

• It provides tissue diagnosis that can guide the extent of resection
• It helps differentiate between lesions requiring different surgical approaches
• The sensitivity (60%) and specificity (90%) are sufficient to change management 1
• It avoids unnecessary major pancreatic surgery if a benign diagnosis (e.g., solid serous adenoma 6 or Castleman disease 7) is confirmed

Common Pitfalls to Avoid

• Do not assume this is a simple pancreatic cyst requiring only surveillance—the size and wall nodularity are worrisome features
• Do not delay EUS-FNA for repeat cross-sectional imaging—the features are already concerning enough to warrant tissue diagnosis
• Ensure the interventional endosonographer targets the solid/nodular component specifically, not just the cystic fluid, as this provides the highest diagnostic yield 2
• Do not perform EUS-FNA if bleeding risk is high (check for coagulopathy or dual antiplatelet therapy) 2

Next Steps After EUS-FNA

• If malignancy or high-grade dysplasia is confirmed: Proceed to surgical resection (likely distal pancreatectomy or central pancreatectomy depending on final staging)
• If benign cytology but concerning features persist: Multidisciplinary tumor board discussion regarding surgical resection versus close surveillance
• If definitively benign diagnosis: Consider surveillance MRI at 1 year, then every 2 years 1