Appendix - L-cell carcinoid tumor (tubular carcinoid)

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Appendix

Other tumors

L-cell carcinoid tumor (tubular carcinoid)

Reviewer: Jaleh Mansouri, M.D. (see Reviewers page)
Revised: 20 October 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

See also carcinoid and goblet cell carcinoid

General
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● Carcinoid tumor, much less common than classic tumors with insular pattern (EC-cell tumors); cell of origin is usually the L-cell, which produces enteroglucagons and peptide YY (Arch Pathol Lab Med 2010;134:1612)
● Minimal metastatic potential

Gross description
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● Small nodules at tip, often not identified grossly

Micro description
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● Columns, ribbons, acini or small tubules of small round cells with pale eosinophilic cytoplasm and round/oval nuclei with small nucleoli
● No/rare mitotic activity
● No insular masses
● May have dominant glandular, infiltrative pattern resembling metastatic carcinoma

Micro images
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Left: typical carcinoid (insular pattern); right: L-cell carcinoid (tubular carcinoid)

Positive stains
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● Chromogranin B, synaptophysin, CEA, glucagon, peptide YY, pancreatic polypeptide

Negative stains
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● Mucin, chromogranin A (usually)

Differential diagnosis
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● Well-differentiated metastatic adenocarcinoma: CK7/CK20 staining is nonspecific and represents potential diagnostic pitfall (J Clin Pathol 2012;65:666)

End of Appendix > Other tumors > L-cell carcinoid tumor (tubular carcinoid)

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