Editing Pancreatic lesions (section)

=== '''Mucinous cystic neoplasms (MCN)''' ===

** Mucin-producing cystic tumours which do not communicate with the pancreatic duct (therefore different from IPMN)
** Pathophysiology
*** Dysplastic neoplasms with clear-cut malignant potential
**** Felt to follow adenoma-to-carcinoma sequence - malignancy risk 5-15%
**** When invasive type, not as aggressive as ductal adenocarcinoma
**** 5 year survival 50-60% expected after resection
**** Mostly offer adjuvant chemotherapy, especially with positive nodes
*** Singular, large, thick-walled cysts, lined with mucin-secreting columnar epithelium, almost never communicating with ductal system
*** Pathology shows 'ovarian-type' stroma within the cyst capsule, typically seen histologically after resection
*** Stain positive for oestrogen and progesterone in most cases
** Presentation
*** Strong female predilection, most commonly seen in body and tail of pancreas
*** Mean age at presentation 45yo
*** 20% have had pancreatitis
*** Often initially misdiagnosed as pseudocyst - to differentiate, may need FNA with aspirate showing a fluid high in mucin and CEA (pseudocyst is higher in amylase)
*** Typically asymptomatic - 50% can have vague abdominal pain
** Imaging
*** Solitary cyst with fine septations and a rim of calcification
*** Eggshell calcification, larger tumour size, or a mural nodule on cross-sectional imaging are suggestive of malignancy
***
** Aspirate
*** Mucin-rich
*** CEA > 192mg/ml
*** Low amylase 
** Management
*** Recommend resection in ALL suitable operative candidates - usually distal pancreatectomy. Curative if no invasive malignant disease.
*** Observation may be considered in medically unfit patients 
* Nondysplastic mucinous cysts (NDMC)
** ''Unclear whether these cysts are entirely benign or represent the earliest stage of MCNs''
** Solid pseudopapillary neoplasm
** Lymphoepithelial cysts