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Exocrine tumors

Adenosquamous carcinoma

Reviewer: Deepali Jain, M.D. (see Reviewers page)
Revised: 10 July 2014, last major update August 2012
Copyright: (c) 2001-2014, PathologyOutlines.com, Inc.


● Tumor with admiixture of malignant squamoid and glandular components (WHO), usually 30% of each
● Rare, M/F = 2:1, mean age 65 years
● Mean survival 6-12 months, poorer than usual type ductal adenocarcinoma (Mod Pathol 2001;14:443, J Surg Res 2012;174:12), but see J Gastrointest Surg 2011;15:165
● Adjuvant chemoradiation therapy improves survival, which is not affected by amount of squamous component (Hum Pathol 2010;41:113)
● Pancreatic squamous cell carcinoma may actually be adenosquamous carcinoma with exuberant squamous component
● Metastases may contain only glandular component

Gross images

Micro images

Various images

Squamous components

Mucoepidermoid pattern

Left: clear cell component; middle: rhabdoid component; right: keratin stains intermediate filaments of rhabdoid cells

45 year old man with acantholytic pattern, osteoclast-like and pleomorphic giant cells


Left: CAM5.2; right: CK13

Cytology description

● Squamous and glandular differentiation, although one component often predominates (Cancer 2003;99:372)
● Extensive necrosis with dense blue globules, squamous ghosts, anucleate squames, atypical single cells, enlarged pyknotic nuclei
● Purely squamous tumor may be metastasis or represent undersampling

Cytology images

Various images

Positive stains

● CK903, CD44 (Arch Pathol Lab Med 2000;124:212), CK5/6 and p63 highlight squamoid portion of tumor
● Otherwise similar immunostaining and Kras mutations as usual ductal adenocarcinoma (Mod Pathol 2009;22:651, Mod Pathol 2005;18:1193)

Differential diagnosis

● Adenoacanthoma: benign squamous component
● Squamous cell carcinoma: no glandular component or mucin staining, even after extensive search

End of Pancreas > Exocrine tumors > Adenosquamous carcinoma

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