Serous Cystadenocarcinoma of the Pancreas

Definition

Same histologic features as serous microcystic adenoma but with metastases or invasion of adjacent organs

WHO 2010 defines requires distant metastases for this diagnosis but cites literature (Galanis 2007, King 2009) that defines malignancy as above
- It appears that invasion of adjacent organs is predictive of (infrequent) later metastases
- Even with distant metastases there are no reports of deaths due to carcinoma

Same histologic features as serous microcystic adenoma
- Innumerable small cysts
  - Most 1-5 mm
    - Scattered larger cysts
  - Sponge-like / honeycomb appearance
- Lined by single layer of flattened or cuboidal cells with clear cytoplasm
  - Abundant glycogen (PAS +, diastase digestible)
  - Rarely eosinophilic cytoplasm
  - Occasional intracystic papillary projections
- Bland cytology
  - Round/oval nuclei
  - No mitotic figures
  - At most, mild cytologic atypia
- Central stellate scar frequently present
  - May calcify
  - Scant stroma otherwise
  - Occasionally entraps other elements
Must demonstrate vascular invasion, metastases or invasion of adjacent organs (see note at top)
- May be otherwise circumscribed
- Most metastases reported to local lymph nodes and liver
- Commonly invaded organs include spleen and stomach
Rare cases have been reported of resected non-invasive serous cystadenomas that recurred later with metastases
No deaths reported due to carcinoma

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting, updates: 1/4/07, 1/4/12