Exocrine carcinomas

Adenosquamous carcinoma

Editorial Board Members: Raul S. Gonzalez, M.D., Wei Chen, M.D., Ph.D.
Deputy Editor-in-Chief: Debra L. Zynger, M.D.
Orhun Çiğ Taşkın, M.D.
Volkan Adsay, M.D.

Last author update: 3 May 2023
Last staff update: 3 May 2023

Copyright: 2002-2023,, Inc.

PubMed Search: Adenosquamous carcinoma pancreas

Orhun Çiğ Taşkın, M.D.
Volkan Adsay, M.D.
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Cite this page: Taşkın OÇ, Adsay NV. Adenosquamous carcinoma. website. Accessed June 6th, 2023.
Definition / general
Essential features
ICD coding
  • ICD-O: 8560/3 - adenosquamous carcinoma
  • Accounts for about ~2% of exocrine pancreatic malignancies
  • M:F = 2:1
  • Mean age of 65 years (Arch Surg 1999;134:599)
  • Ionizing radiation of the pancreas may predispose to the occurrence of adenosquamous carcinoma (Mod Pathol 2001;14:443)
  • Generally discovered with radiology and confirmed on fine needle aspiration biopsy (FNAB) or resection
Radiology description
Radiology images

Contributed by Orhun Çığ Taşkın, M.D.

Cystic and necrotic changes

Prognostic factors
  • Similar to PDAC, stage is the most important prognostic factor
Case reports
Gross description
  • Large, firm mass of the pancreas, with ill defined borders, often with necrotic component, with or without cystic areas
  • Some cases are more demarcated
  • Reference: World J Gastrointest Oncol 2015;7:132
Microscopic (histologic) description
  • Adenocarcinoma component can bare all the characteristics of classic pancreatic ductal adenocarcinoma
  • Squamous component can show keratinization with intercellular bridges or sheets of squamous cells with keratohyaline granules or pearls
    • Some are adenoacanthoma-like, with bland mature squamous elements, whereas others are more basal-like (with high N:C ratio and basophilic appearance)
  • Adenocarcinoma and squamous components can vary greatly in the amount and distribution
  • Sarcomatous component can also be encountered (Anticancer Res 2019;39:4575)
Microscopic (histologic) images

Contributed by Orhun Çığ Taşkın, M.D., Raul S. Gonzalez, M.D. and AFIP

Glandular and squamous components


Adenocarcinoma and squamous carcinoma

Squamous components

Mucoepidermoid pattern



Cytology description
  • Squamous component may be undersampled but malignant squamous cells are highly significant for the diagnosis (Acta Cytol 2013;57:139)
  • Glandular and squamous components can both be distinguished
  • Dense globules, silhouettes of squamous cells, anucleate squames, atypical cytoplasm and enlarged pyknotic nuclei are present in the prominent necrotic background
  • Sheets and clusters of atypical cells with nuclei of variable sizes and shapes (Cancer 2003;99:372)
Cytology images

Contributed by Orhun Çığ Taşkın, M.D.

Pap stain

Cell block

Cell block, p40

Positive stains
Negative stains
Molecular / cytogenetics description
Sample pathology report
  • Pancreas, resection:
    • Adenosquamous carcinoma (see synoptic report)
Differential diagnosis
Board review style question #1
A 65 year old man presented with back pain and severe weight loss. Radiologic images showed a 4 cm relatively round, lobulated mass with extensive central necrosis in the pancreatic body. He underwent resection. Histologic sections demonstrate conventional ductal adenocarcinoma admixed with sheets of squamous cells with keratohyaline granules and intercellular bridges. Which of the following immunohistochemical stains would be positive in this case?

  1. Beta catenin nuclear expression
  2. Chromogranin A
  3. p63
  4. Synaptophysin
Board review style answer #1
C. p63. The histology described in this case is consistent with pancreatic adenosquamous carcinoma. The squamous components should be positive with p63 immunohistochemistry. Neuroendocrine neoplasms are positive for chromogranin and synaptophysin. Beta catenin nuclear expression is observed in solid pseudopapillary neoplasm.

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Reference: Adenosquamous carcinoma
Board review style question #2

Which of the following is true for adenosquamous carcinoma of the pancreas?

  1. It has a better prognosis than ordinary pancreatic ductal adenocarcinoma
  2. It is the most common type of pancreatic malignancy
  3. It usually affects pediatric patients
  4. p63 specifically highlights the squamous component
Board review style answer #2
D. p63 specifically highlights the squamous component. The squamous components of the tumor should be positive with p63 immunohistochemistry. Answer A is incorrect as adenosquamous carcinomas behave worse than pancreatic ductal adenocarcinomas. Answer B is incorrect as pancreatic ductal adenocarcinoma is the most common pancreatic malignancy. Answer C is incorrect as adenosquamous carcinomas occur in elder patients (mean age of 65 years).

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Reference: Adenosquamous carcinoma
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