SEROUS CYSTADENOMA OF PANCREAS

SEROUS CYSTIC NEOPLASM OF PANCREAS

Both serous and mucinous neoplasms are grouped as cystadenoma or cystadenocarcinoma though serous cystic neoplasms are benign while  mucinous cystic neoplasms have significant malignant potential.

Microcystic serous cystadenoma

• It is benign epithelial neoplasm composed of uniform cuboidal glycogen rich cells that form numerous small cysts containing serous fluid.
• General features
  • Account for 1 to 2% of all neoplasms of exocrine pancreas.
  • Sex- common in females with F:M ratio of 7:3
  • Age-Mean age 65 years (range 18 to 91 years)
• Syndromes associated
  • Von Hippel Lindau syndrome – Serous cystadenomas are associated with VHL syndrome (Autosomal dominant disorder characterised hemangioblastomas of CNS and retina, renal neoplasms and cysts, clear cell endocrine pancreatic neoplasm, clear cell papillary cystadenoma of epididymis, clear cell carcinoid tumors of biliary tree, endolymphatic sac tumor and pheochromocytomas.
  • Evans syndrome (one case in literature)
• Clinical features
  • Presents as large abdominal mass  that can be palpated.
  • Common symptoms include-Abdominal pain, early satiety, weight loss, dyspepsia, nausea and vomiting
  • Less common –jaundice, acute appendicitis, GI bleeding.
• Imaging:
  • CT scan- well defined mass with microlacunae separated by delicate septa. Centre of the lesion shows stellate scar and 10 to 30% of these scars show a “Sun burst” pattern  of calcification.
  • MRI– Demonstrate the cystic nature of lesion. Tend to have low intensity on T1- weighted images and high intensity on T2-weighted images.
  • Endoscopic ultrasound– reveals an echogenic mass with numerous (usually more than 6) small (usually less than 2cms) cysts that produce a characteristic “soap bubble” pattern.
  • ERCP- extrinsic compression or “ draping” of pancreatic duct and the absence of any communication between the neoplastic cysts and the man pancreatic duct.
• Serum markers:
  • CEA,   CA-19-9 and CA-25 –   Never raised in serum
  • Cyst fluid – CEA levels-low (less than 100mg/ml)in serous neoplasms high (more than 100mg/ml) in mucinous
• Gross
  • Solitary involving head and body/tail (multifocal in VHL) tend to be large well demarcated with bosselated surface and composed of numerous small cysts which are  thin walled (less than 2mm upto 1cm) giving honey comb or sponge appearance
  • Cysts are filled with clear watery straw coloured fluid and are separated by thin fibrovascular septa.
  • Centre of the neoplasms contain stellate scar with foci of calcification
• Microscopic
  • Lined by single layer of uniform clear cuboidal cells they forms sheets or papillae.
  • Clear cytoplasm is due to abundance of intracellular glycogen.
  • Nuclei are small and round and are uniform hyperchromatic with inconspicuous nucleoli.
  • Adjacent pancreatic parenchyma is often atrophic particulary if pancreatic duct is obstructed.
• Histologic types:
  • Four variants: 
    • Macrocystic serous cystadenoma- known as oligocystic serous cystadenoma characterised by cysts that are larger less well defined and fewer in number. On IHC tumor cells are positive  for EMA and Cytokeratin CK-7,8,18,19 
    • Solid serous adenoma – These neoplasms have two components and they are well differentiated pancreatic endocrine neoplasm and serous cystadenoma 
    • VHL associated serous cystic neoplasm. Tumor cells are positive for EMA, inhibin, CK7,CK8,CK18, CK19.

• Immunohistochemistry –  serous cystadenomas are positive for Cytokeratin, α –inhibin, MUC 6.
• Treatment –  surgical resection
• Prognosis– excellent. Death in few cases occurred due to GI bleeding from erosion of neoplasm in the duodenum malabsorption  and obstruction of the biliary tree.

References 

• Ralph H. Hruban, Martha Bishop Pitman, David S. Klimstra. Serous Cystic Neoplasms.In: Tumors of the Pancreas. AFIP Atlas of Tumor Pathology Series 4;33-47.