TY - JOUR
T1 - Loss of BAP1 expression in atypical mesothelial proliferations helps to predict malignant mesothelioma
AU - Pillappa, Raghavendra
AU - Maleszewski, Joseph J.
AU - Sukov, William R.
AU - Bedroske, Patrick P.
AU - Greipp, Patricia T.
AU - Boland, Jennifer M.
AU - Yi, Eunhee S.
AU - Peikert, Tobias
AU - Aubry, Marie Christine
AU - Roden, Anja C.
N1 - Publisher Copyright:
Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.
PY - 2018
Y1 - 2018
N2 - Distinguishing reactive mesothelial proliferation from malignant mesothelioma (MM) can be difficult, particularly on small biopsies. In this scenario, a diagnosis of atypical mesothelial proliferation might be rendered. However, the distinction between a reactive process and MM is important for prognosis and treatment. Recently, loss of BRCA1-associated protein 1 (BAP1) expression and/or homozygous deletion of CDKN2A were identified in some MM, but not in reactive mesothelial proliferations. We studied 34 cases of atypical mesothelial proliferation from our institutional files (1993 to 2016) for BAP1 expression, deletion of CDKN2A, and clinical outcome. Fifteen of 34 patients (44%) were subsequently diagnosed with MM. BAP1 expression was lost in 6 of these 15 (40%) patients. Ten of 15 (67%) patients died of disease within a median time of 18.2 months. BAP1 expression was also lost in 1 case of probable MM. In this case atypical mesothelial proliferation was identified in the pleura during a lobectomy procedure for lung adenocarcinoma. Follow-up of 57.0 months was remarkable for visceral and parietal pleural thickening with continued unilateral effusion identified on imaging studies but no subsequent definitive diagnosis of MM. CDKN2A studies by fluorescence in situ hybridization (performed in 31 cases) found no homozygous deletion of that gene in any case. In conclusion, loss of BAP1 expression in atypical mesothelial proliferation helps to predict MM and is a useful adjunct test in these cases. Homozygous deletion of CDKN2A in mesothelial cell proliferations did not prove to be useful to predict MM in cases of atypical mesothelial proliferation.
AB - Distinguishing reactive mesothelial proliferation from malignant mesothelioma (MM) can be difficult, particularly on small biopsies. In this scenario, a diagnosis of atypical mesothelial proliferation might be rendered. However, the distinction between a reactive process and MM is important for prognosis and treatment. Recently, loss of BRCA1-associated protein 1 (BAP1) expression and/or homozygous deletion of CDKN2A were identified in some MM, but not in reactive mesothelial proliferations. We studied 34 cases of atypical mesothelial proliferation from our institutional files (1993 to 2016) for BAP1 expression, deletion of CDKN2A, and clinical outcome. Fifteen of 34 patients (44%) were subsequently diagnosed with MM. BAP1 expression was lost in 6 of these 15 (40%) patients. Ten of 15 (67%) patients died of disease within a median time of 18.2 months. BAP1 expression was also lost in 1 case of probable MM. In this case atypical mesothelial proliferation was identified in the pleura during a lobectomy procedure for lung adenocarcinoma. Follow-up of 57.0 months was remarkable for visceral and parietal pleural thickening with continued unilateral effusion identified on imaging studies but no subsequent definitive diagnosis of MM. CDKN2A studies by fluorescence in situ hybridization (performed in 31 cases) found no homozygous deletion of that gene in any case. In conclusion, loss of BAP1 expression in atypical mesothelial proliferation helps to predict MM and is a useful adjunct test in these cases. Homozygous deletion of CDKN2A in mesothelial cell proliferations did not prove to be useful to predict MM in cases of atypical mesothelial proliferation.
KW - Atypical mesothelial proliferation
KW - BAP1
KW - CDKN2A
KW - Malignant mesothelioma
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U2 - 10.1097/PAS.0000000000000976
DO - 10.1097/PAS.0000000000000976
M3 - Article
C2 - 29076876
AN - SCOPUS:85043715785
SN - 0147-5185
VL - 42
SP - 256
EP - 263
JO - American Journal of Surgical Pathology
JF - American Journal of Surgical Pathology
IS - 2
ER -