In:
Histopathology, Wiley, Vol. 69, No. 5 ( 2016-11), p. 727-738
Abstract:
Molecular investigation of small‐cell carcinoma of the ovary, hypercalcaemic type ( SCCOHT ) has revealed that it is a monogenetic tumour characterized by alteration of SMARCA 4 ( BRG 1 ), encoding a member of the switch/sucrose non‐fermentable ( SWI / SNF ) chromatin remodelling complex. A large majority of cases show loss of expression of the corresponding SMARCA 4/ BRG 1 protein. Furthermore, three cases of SCCOHT with retained SMARCA 4 protein expression showed loss of SMARCB 1/ INI 1 expression. The aim of this study was to assess the sensitivity and specificity of loss of SMARCA 4 expression as a diagnostic test for SCCOHT . Methods and results We performed SMARCA 4 and SMARCB 1 staining in 245 tumours, many of which were potentially in the differential diagnosis of SCCOHT . We also stained 56 cases of SCCOHT for SMARCA 4 and 37 of these for SMARCB 1. Fifty‐four of the SCCOHT cases showed complete absence of SMARCA 4 expression. The two cases with retained expression showed molecular alteration of SMARCA 4 . Of the 217 other neoplasms with interpretable staining, all retained SMARCA 4 expression. Although the majority showed diffuse, strong nuclear expression, a heterogeneous, typically weak staining pattern was present in 13% of cases. All 37 cases of SCCOHT tested and all other neoplasms, apart from three malignant rhabdoid tumours, showed retained nuclear SMARCB 1 expression. Loss of SMARCA 4 expression had a sensitivity of 96.55% and specificity of 100%. Conclusions Loss of SMARCA 4 expression is sensitive and specific for SCCOHT . Although some mimics show heterogeneous expression, there is retention of nuclear staining in at least a part of the tumour; therefore, only complete loss of staining should be regarded as being supportive of SCCOHT .
Type of Medium:
Online Resource
ISSN:
0309-0167
,
1365-2559
DOI:
10.1111/his.2016.69.issue-5
Language:
English
Publisher:
Wiley
Publication Date:
2016
detail.hit.zdb_id:
2006447-0
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