Volume 65, Issue 1 pp. 51-59
Original Article

A diagnostic immunohistochemical panel for yolk sac (primitive endodermal) tumours based on an immunohistochemical comparison with the human yolk sac

Francisco F Nogales

Corresponding Author

Francisco F Nogales

Departments of Pathology, San Cecilio University Hospital, Granada, Spain

Address for correspondence: F F Nogales, Department of Pathology, Facultad de Medicina, Avenida de Madrid 11, 18012 Granada, Spain. e-mail: [email protected]Search for more papers by this author
Enoe Quiñonez

Enoe Quiñonez

Departments of Pathology, San Cecilio University Hospital, Granada, Spain

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Laura López-Marín

Laura López-Marín

Dr Abelardo Buch López Institute of Nephrology, Havana, Cuba

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Isabel Dulcey

Isabel Dulcey

Departments of Pathology, San Cecilio University Hospital, Granada, Spain

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Ovidiu Preda

Ovidiu Preda

Master Diagnostica, Granada, Spain

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First published: 20 January 2014
Citations: 48

Abstract

Aims

To establish a diagnostic immunohistochemical panel for various histotypes of yolk sac (primitive endodermal) tumours (YSTs) by comparison with the human yolk sac (HYS) immunophenotype.

Methods and results

Twenty-five YSTs showing either classical patterns (CPs) of histology (microcystic/reticular, = 14; polyvesicular, = 1; and hepatoid, = 1) or somatic glandular patterns (SGPs; = 9) were analysed for expression of α-fetoprotein (AFP), glypican-3 (GPC3), villin, hepatocyte paraffin-1 (HepPar-1), CDX2, SALL4 and LIN28. AFP expression was constantly heterogeneous in CPs but tended to be focal/absent in SGPs. GPC3 was diffuse in CPs but heterogeneous (seven cases) or focal/absent (two cases) in SGPs. HepPar-1 expression was focal in all but three cases (diffuse in one CP-hepatoid and two SGPs). CDX2 positivity was focal in CPs but heterogeneous (seven cases) or diffuse (two cases) in SGPs. Villin, SALL4 and LIN28 were diffusely positive in nearly all cases.

Conclusions

CPs reproduce the immunophenotype of HYS and early endoderm with variable expression of both AFP and markers of early gut or hepatic differentiation. SGPs with intestinal differentiation often have incomplete immunophenotypes. A differential diagnosis panel, including both markers of pluripotentiality (SALL4 and/or LIN28) and endoderm (AFP, GPC3 and villin), is proposed. It identifies overlapping multidifferentiation of primitive and somatic immunophenotypes, supporting the recently proposed term of primitive endodermal tumours.

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