Clinicopathologic Re-Evaluation of 100 Malignant Fibrous Histiocytomas: Prognostic Relevance of Subclassification

Abstract

This retrospective study confirms that most so-called MFH can be subclassified by defined criteria; it provides evidence that such classification is clinically important. Specifically, pleomorphic STS showing myogenic differentiation are significantly more aggressive, a finding that allows planning future therapeutic trials.

Smooth muscle differentiation identifies two classes of poorly differentiated pleomorphic sarcomas with distinct outcome

“…14 However transgelin, such as SMA and calponin, is not exclusively expressed in smooth muscle tumors, so they cannot be considered specific to smooth myogenic differentiation. 8,15,16 In contrast, h-CD appeared specific, but lacked sensitivity. 14 The smooth muscle differentiation classification method, taking into account not only positivity for smooth muscle markers but also their labeling intensity, exhibited the strongest prognostic value compared with other prognostic factors, including histological classification.…”

“…The clinical relevance of better identification of undifferentiated pleomorphic sarcomas has been previously shown, especially in cases of undifferentiated pleomorphic sarcomas with myogenic differentiation, which seem to be significantly more aggressive. 8,9 In the present study, we assessed whether by taking into account the immunohistochemical labeling for four smooth muscle differentiation markers, we could propose a diagnostic and prognostic tool to classify sarcomas with complex genetics. According to this smooth muscle differentiation classification method, 25% of tumors were rediagnosed in another histotype.…”

“…7 Many studies have re-evaluated and questioned the existence of this type of sarcoma according to the hypothesis that undifferentiated pleomorphic sarcomas could actually represent a common morphologic phenotype shared by various poorly differentiated soft-tissue sarcomas. [8][9][10] The clinical relevance of a better method of diagnosing undifferentiated pleomorphic sarcomas has been demonstrated, especially in cases of undifferentiated pleomorphic sarcomas with myogenic differentiation, which seem to be significantly more aggressive. 8,9 In a previous study, we demonstrated that the MYOCD gene is amplified and overexpressed in a large proportion of leiomyosarcomas.…”

“…[8][9][10] The clinical relevance of a better method of diagnosing undifferentiated pleomorphic sarcomas has been demonstrated, especially in cases of undifferentiated pleomorphic sarcomas with myogenic differentiation, which seem to be significantly more aggressive. 8,9 In a previous study, we demonstrated that the MYOCD gene is amplified and overexpressed in a large proportion of leiomyosarcomas. We have also shown that MYOCD expression level controlled smooth muscle differentiation protein expression and had an impact on cell migration in sarcomas.…”

Gene expression analysis of soft tissue sarcomas: characterization and reclassification of malignant fibrous histiocytoma

“…2 Among them, diagnosis of MFH has been the most controversial issue. [3][4][5] MFH has been considered the most common soft tissue sarcoma of adults; it is manifested by a broad range of histological appearances and consists of four subtypes: storiform and pleomorphic type, myxoid type, giant cell type and inflammatory type. Recent clinicopathological, ultrastructural and immunohistochemical studies revealed that MFH shows no evidence of true histiocytic differentiation and that it is not a single entity but rather a heterogeneous collection of pleomorphic subtypes of other sarcomas.…”