Impact on Survival of Nuclear Atypia in Epithelioid Malignant Mesothelioma

Abstract

Introduction: Malignant pleural mesothelioma is a rare tumour with a bad prognosis. The only consensual prognostic factors are represented by the stage and the histologic type. Concerning the histologic type, epithelioid mesothelioma is known to have better prognosis in comparison with the sarcomatoid and biphasic types. Epithelioid mesotheliomas have been reported to be a heterogeneous prognostic group. Our aim was to assess the impact on the survival of different characteristics of epithelioid mesothelioma, including nuclear atypia, mitotic count, MIB-1 index, inflammatory host response, stromal desmoplasia, necrosis, vascular emboli and invasion depth. Material and methods: We performed a study of survival of 30 malignant pleural mesotheliomas according to the different parameters studied. Results: The study included 26 women and 4 men. The mean age of the patients was 61 years. The microscopic exam concluded to an epithelioid mesothelioma in 17 cases, sarcomatoid mesothelioma in 4 cases and biphasic mesothelioma in 9 cases. The 17 cases of epithelioid mesothelioma developed severe nuclear atypia in 6 cases and mild nuclear atypia in 11 cases. The mitotic count and the MIB-1 score were respectively inferior to 5 mitoses/50 HPF and inferior to 10% in 11 cases and were superior to 5 mitoses/50 HPF and superior to 10% in 6 cases. No vascular emboli were recorded. Tumour necrosis was reported in 1 case. The inflammatory host response was severe in 4 cases and mild in 13 cases. The tumoral stroma was desmoplastic in 4 cases. The invasion depth was superior to 0.5mm in 16 cases. The median overall survival amounted to 180 days. Nuclear atypia was the only feature that had impact on survival in the group of epithelioid mesothelioma. Conclusion:Our results highlight the correlation of nuclear atypia with survival.

Reliability of assessing morphologic features with prognostic significance in cytology specimens of epithelioid diffuse pleural mesothelioma and implications for cytopathology reporting

“…patients with E-DPM showed that nuclear atypia was the only feature that affected survival in these patients. 56 In the current study, we show that the nuclear atypia score in all paired cytology and surgical pathology specimens was identical. Based on these findings, we conclude that assessment of nuclear atypia in cytology specimens of E-DPM is reliable.…”

“…Despite the absence of mitotic count, reporting the other components of the 2021 WHO nuclear grade, nuclear atypia score and the presence or absence of tumor necrosis, in cytology reports could provide prognostically significant information that could inform management decisions in the absence of the formal nuclear grade. In fact, a small study of 17 patients with E‐DPM showed that nuclear atypia was the only feature that affected survival in these patients 56 . In the current study, we show that the nuclear atypia score in all paired cytology and surgical pathology specimens was identical.…”

Importance of Histopathological Grading for Treatment Selection in Malignant Mesothelioma

“…8 Mlika et al also noted a significant relationship between nuclear atypia and survival time in their smaller-scale study. 12 In the present study, we determined that nuclear atypia grade and nuclear grade significantly affect survival time regardless of treatment type.…”

A panel of emerging EMT genes identified in malignant mesothelioma

“…However, within patients with epithelioid subtype, there is a lack of good prognostic markers even though some tumors are more aggressive than others. Nuclear atypia could have an impact on survival in epithelioid mesothelioma, and nuclear grade was confirmed to correlate with survival in a multi-institutional study 39 , 40 , but further studies will be required to demonstrate the validity of this marker in clinical practice.…”