Cystic Neoplasms of Pancreas

Serous Cystic Neoplasm

• Most common site : Head
• M=F
• Microcystic
• Central calcification in 10 -20% of cases (Not s/o malignancy)
• Benign
• Increasing size (>4cm) needs resection (diagnostic dilemma)
• Glycogen rich [PAS positive] multinucleate cells on pathology

Mucinous Cystic Neoplasm

• ovarian stroma = F>>>M = ER;PR positive
• Most Common in BODY & TAIL of pancreas
• H/o Pancreatitis seen in 20% of cases
• CT findings:
  • Oligocystic or Macrocystic
  • Egg shell ( peripheral) Calcification / sometimes calcification in centre also ; mural nodule
• Calcification and Mural nodule is a risk factor for malignancy
• CEA levels >192 mg/dl implies whether the tumor is mucinous or non mucinous. It doesnot comment on the invasive component of tumor
• IF CEA >192 ⇒ look for amylase levels
  • ⇒ if elevated ⇒ IPMN
  • ⇒ if not elevated ⇒ MCN because they dont communicate with pancreatic duct
• Treatment = Resection
  • lesion in head = whipples
  • lesion in body or tail = Distal Pancreatectomy

PSEUDOCYST Of Pancreas

• Normal CEA levels with elevated amylase levels
• 25% of Cystic neoplasms also present with pancreatitis so dont diagnose by the clinical picture.
  • look for CEA levels and amylase levels.

IPMN

• Most Common Cystic Neoplasm of Pancreas = BD - IPMN
• Most Common Cystic lesion of pancreas = Pseudocyst

• Risk of Malignancy:
  • Overall, for BD-IPMN, the risk of invasive malignant disease is approximately 2% to 3% per year.
  • Individuals with MD-IPMN have a 30% to 50% risk of harboring invasive pancreatic cancer at the time of presentation.
• Size guidelines:
  • Current guidelines suggest that main duct dilation of more than 5 mm is consistent with a diagnosis of MD-IPMN and a worrisome feature, while more than 1 cm is considered high risk.
• 3 types of metaplasia in IPMN:
  • Gastric subtype : BD-IPMN ⇒ not a strong risk factor of invasive malignancy
  • Intestinal subtype : Colloid variety = Best prognosis compared to Tubular
  • Pancreaticobiliary : Tubular variety ⇒ also seen in PDAC ⇒ worst prognosis
• Fish Mouth appearance on Endoscopy:

  • 

Genetic Mutations in IPMN:

• SMAD 4 inactivation is not seen in IPMN
• P53, KRAS (+)
• GNAS in 66% of cases
• GNAS more common in colloid variety
• KRAS more common in tubular variety
• Colloid > Tubular

Worrisome and High Risk Features of IPMN:

Management of Suspected BD - IPMN:

• Different scenario’s of features
  • High risk features ( atleast 1 positive) ⇒ Surgery
  • High risk features Negative
    • Worrisome positive( atleast 1 ) ⇒ EUS done
      • In EUS look for
        1. Mural nodule >5mm
        2. Main Duct suspicious of involvement
        3. Cytology suspicious of Malignancy
      • In EUS ⇒ any one of above 3 positive ⇒ go for Resection
      • In EUS ⇒ above 3 negative or incolnclusive ⇒ LOOK FOR SIZE OF CYST AND PLAN ACCORDINGLY with follow up
    • Worrisome Negative ⇒ LOOK FOR SIZE OF CYST AND PLAN ACCORDINGLY with follow up
    • Size Criteria and investigations to be done on follow up:
      • <1cm ⇒ CT / MRI in 6 months and then every 2 years
      • 1-2 cm ⇒ CT / MRI in 6 months for 2 years and then every 2 years
      • 2-3 cm ⇒ EUS in 3-6 months upto 1 year [ consider surgery if young]

      • 3 cm ⇒ MRI with EUS alternating every 3-6 months [ STRONGLY CONSIDER SURGERY IF YOUNG]

Management of MD - IPMN:

• Strongly consider for surgery in these cases as risk of malignancy is very high

SPEN:

• Frantz tumor, hamoudi tumors
• Young female ( 9:1) ; Mean age = 29 yrs
• Mostly symptomatic (only 15% are asymptomatic); Often large tumors
• Tail >head
• CT Findings:
  • encapsulated lesions with necrosis and hemorrhage
  • calcifications, solid and cystic component
  • no ductal dilatation

Pathology of SPEN:

• Histopathology
  • Polygonal epithelial cells
  • Positive for:
    • Vimentin
    • Keratin
    • NSE
    • CD 10
    • Progesterone
    • AMACR
  • Negative for:
    • Estrogen
    • Chromogranin
  • Abnormal beta-catenin expression
  • Absence of:
    • KRAS mutation
    • GNAS mutation
    • SMAD 4 mutation
  • Most common mutation: CTNNB1 exon 3 (APC-Beta catenin pathway)
  • Metastatic disease in 15%

Clinical Characteristics and Management of SPTs

• Indolent Nature:
  • Generally indolent and typically cured with complete surgical extirpation.
  • Long-term survival after resection is common.
• Surgical Considerations:
  • CT picture is of SPEN head of pancreas (Well defined, solid cystic areas, in young female, central calcification with peripheral enhancement with central necrosis ) Preoperative FNAC is not required in most cases. However, because of the tumor"s largely necrotic composition, FNA biopsy can frequently be nondiagnostic. Given the unpredictable but real metastatic potential of these tumors, surgical resection is recommended for all patients with localized SPT. Although these tumors may be extremely large and can invade critical vasculature, most lesions are usually amenable to complete resection. Pancreaticoduodenectomy or distal pancreatectomy can be performed with en bloc resection of involved adjacent organs when indicated. The genetic profile associated with SPT is different from adenocarcinoma, most notably for an absence of KRAS, GNAS, and SMAD4 mutations. Almost all SPTs harbor alterations in the APC/ß-catenin pathway due to a mutation involving CTNNB1 (exon 3))
  • Significant vascular invasion is the most common reason for the inability to resect these lesions.
  • Metastatic disease is present in as many as 15% of patients.
• Criteria for Malignancy:
  • Locally advanced disease with vascular invasion precluding resection.
  • Presence of lymph node or hepatic metastasis.
• Long-Term Survival:
  • Often possible despite the presence of malignant factors such as metastatic disease.
  • Should not preclude resection in selected cases.
• Progression Rate:
  • Estimated around 2.6% after initial surgery for nonmetastatic SPTs (based on a meta-analysis of literature between 2002 and 2017).
• Risk Factors for Progression:
  • Male gender
  • Positive lymph nodes
  • Positive margin at the time of resection
  • Lymph vascular invasion

Pseudocyst Vs SCN Vs MCN vs IPMN vs SPT :

Diagnosis And Tumor Markers Summary: