Exocrine carcinomas

Medullary carcinoma

Editorial Board Member: Wei Chen, M.D., Ph.D.
Deputy Editor-in-Chief: Aaron R. Huber, D.O.
Pierre Tran, B.A.
Beena Ahsan, M.D.

Last author update: 29 August 2023
Last staff update: 29 August 2023

Copyright: 2002-2023,, Inc.

PubMed Search: Medullary carcinoma pancreas

Pierre Tran, B.A.
Beena Ahsan, M.D.
Page views in 2023 to date: 1,532
Cite this page: Tran P, Xia R, Ahsan B. Medullary carcinoma. website. Accessed September 27th, 2023.
Definition / general
  • Rare histologic variant of pancreatic ductal adenocarcinoma (PDAC) characterized by poor differentiation, pushing borders and a syncytial growth pattern
Essential features
  • Main histologic features are poor differentiation with limited gland formation, syncytial growth pattern and pushing borders
  • Prominent tumor infiltrating lymphocytes (TILs) are common
  • Associated with microsatellite instability (MSI) and wild type KRAS status
  • Represents < ~4% of PDAC cases
  • 26 reported cases in the literature
  • References: Am J Pathol 1998;152:1501, Front Oncol 2023;12:1082927
  • Pancreatic medullary carcinoma
  • Medullary pancreatic carcinoma
ICD coding
  • ICD-10: C25.9 - malignant neoplasm of pancreas
  • ICD-11: 2C10.0 - adenocarcinoma of pancreas
  • Cancer screening in the patient's immediate family following diagnosis of medullary pancreatic carcinoma has been suggested (Am J Pathol 2000;156:1641)
  • Accumulated risk of pancreatic cancer in Lynch syndrome patients is 3.7% and tumors often have characteristic medullary morphology (J Cancer 2017;8:3667)
  • No known associations with race, gender, age, alcohol use or tobacco use
  • Hereditary syndromes: Lynch syndrome
Clinical features
  • Epigastric pain, back pain, jaundice, weight loss, diabetes mellitus
  • Abdominal CT scan or MRI
  • Endoscopic ultrasound guided fine needle aspiration (EUS FNA)
  • Histologic evaluation of surgical resection specimen
  • Serum elevation of CA19-9 or CEA
Radiology description
Prognostic factors
Case reports
Gross description
  • There are no definitive diagnostic criteria to grossly distinguish medullary carcinoma from conventional PDAC; it may show circumscribed borders as compared to infiltrative borders of conventional PDAC (Pathologica 2020;112:210)
Microscopic (histologic) description
  • Well circumscribed tumor with pushing / expansile borders
  • Syncytial growth pattern with poorly defined cell borders
  • Solid pattern of growth (sheets and nests) with limited gland formation
  • Tumor cells with pleomorphic nuclei, prominent nucleoli and abundant amphophilic cytoplasm
  • Large areas of necrosis may be present
  • Abundant lymphocytes within and around tumor
  • Focal clear cells and squamoid differentiation have also been reported (Am J Pathol 2000;156:1641)
Microscopic (histologic) images

Contributed by Rong Xia, M.D., Ph.D. and Beena Ahsan, M.D.
circumscribed borders

Circumscribed borders

sheet-like growth pattern

Sheet-like growth pattern

syncytial growth pattern

Syncytial growth pattern

positive p63 immunostain

Positive p63 immunostain

Positive stains
Negative stains
Molecular / cytogenetics description
Sample pathology report
  • Pancreas, Whipple resection:
    • Poorly differentiated carcinoma, consistent with medullary carcinoma (x cm in maximum dimension)
    • Resection margins are negative for carcinoma (mention the positive margin, if any)
    • Negative / positive for perineural and lymphovascular invasion
    • All lymph nodes are negative for carcinoma
Differential diagnosis
  • Poorly differentiated PDAC:
    • Infiltrative growth pattern, well to poorly formed glands and desmoplastic stroma, KRAS mutated, microsatellite stable
  • EBV associated lymphoepithelioma-like carcinoma:
    • EBV encoded RNA (EBER) in situ hybridization positive
Board review style question #1

Which of the following is characteristic of medullary carcinoma in the pancreas?

  1. EBV encoded RNA (EBER) in situ hybridization positive
  2. Infiltrative growth pattern with well to poorly formed glands
  3. KRAS mutations
  4. MSS (microsatellite stable)
  5. Pushing borders with syncytial growth pattern, limited to no gland formation and tumor infiltrating lymphocytes
Board review style answer #1
E. Pushing borders with syncytial growth pattern, limited to no gland formation and tumor infiltrating lymphocytes. Expansile invasion (pushing borders), poorly defined cell borders (syncytial growth) and little to no glandular formation (poor differentiation) are the 3 main characteristics of medullary carcinoma in the pancreas. Abundant tumor infiltrating lymphocytes are also present. Answer D is incorrect because medullary carcinoma of the pancreas is associated with microsatellite instability (MSI), which may aid in the diagnosis. Answer C is incorrect because unlike conventional PDAC, medullary carcinoma of the pancreas is associated with wild type KRAS status. Answer A is incorrect because EBV encoded RNA (EBER) in situ hybridization positivity describes EBV associated lymphoepithelioma-like carcinoma. Answer B is incorrect because medullary carcinoma of the pancreas lacks well formed glands and is defined by syncytial growth pattern.

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Reference: Medullary carcinoma
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