Schürch W, Bégin L R, Seemayer T A, Lagacé R, Boivin J C, Lamoureux C, Bluteau P, Piché J, Gabbiani G
Department of Pathology, Hôtel-Dieu Hospital of Montrael, P.Q., Canada.
Am J Surg Pathol. 1996 Feb;20(2):131-47. doi: 10.1097/00000478-199602000-00001.
325 diverse sarcomas, 39 rhabdomyosarcomas (RMS), including all histologic variants, and 135 leiomyosarcomas (LMS) were identified. Within these two groups, 18 (46%) of the RMS and 14 (10%) of the LMS represented pleomorphic variants. These neoplasms were studied by morphology (histology and ultrastructure) and by immunohistochemical methods employing antibodies to intermediate filaments (vimentin and desmin) and actin isoforms [alpha-smooth (sm) and alpha-sarcomeric (sr) actins]. Twenty-four pleomorphic malignant fibrous histiocytomas (MFH) and eight pleomorphic liposarcomas (LS) were examined in a similar fashion. By light microscopy, the pleomorphic RMS, LMS, and MFH were indistinguishable, as each was dominated by pleomorphic cells disposed in a haphazard growth pattern; moreover, many featured fascicular, storiform, and sclerotic zones. The distinction between these neoplasms became apparent only following immunohistochemistry and/or ultrastructural study. All pleomorphic RMS disclosed rudimentary sarcomeres and exhibited the following cytoskeletal profile: vimentin (+) (18 of 18), desmin (+) (14 of 18), alpha-sr actin (+) (18 of 18) and alpha-sm actin (+) (five of 18). All the pleomorphic LMS featured smooth-muscle differentiation of variable degrees in the form of cytoplasmic bundles of microfilaments and associated dense bodies; their cytoskeletal profile was vimentin (+) (14 of 14), desmin (+) (seven of 14), alpha-sr actin (+) (none of 14), and alpha-sm actin (+) (eight of 14). The latter was demonstrated in all moderately differentiated, but absent or only focally expressed in poorly differentiated variants. All pleomorphic MFH and LS were devoid of myogenic (skeletal or smooth) ultrastructural features and expressed vimentin solely. This combined morphological and immunohistochemical study illustrates the following: First, these pleomorphic sarcomas are often indistinguishable by histologic growth pattern alone; thus, an accurate diagnosis requires study with all of these techniques. Second, pleomorphic myogenic sarcomas are restricted to adults and are not uncommon neoplasms among pleomorphic sarcomas: RMS (28%), LMS (21%), MFH (38%), and LS (13%). Third, the study defines desmin-negative and alpha-sm actin-positive pleomorphic RMS, and desmin-negative and alpha-sm-actin-negative pleomorphic LMS.
共鉴定出325例不同类型的肉瘤，39例横纹肌肉瘤（RMS），包括所有组织学变体，以及135例平滑肌肉瘤（LMS）。在这两组中，18例（46%）RMS和14例（10%）LMS为多形性变体。通过形态学（组织学和超微结构）以及采用针对中间丝（波形蛋白和结蛋白）和肌动蛋白异构体[α-平滑肌（sm）和α-肌节（sr）肌动蛋白]的抗体的免疫组织化学方法对这些肿瘤进行了研究。以类似方式检查了24例多形性恶性纤维组织细胞瘤（MFH）和8例多形性脂肪肉瘤（LS）。通过光学显微镜观察，多形性RMS、LMS和MFH难以区分，因为每一种都以杂乱生长模式排列的多形性细胞为主；此外，许多还具有束状、席纹状和硬化区。这些肿瘤之间的区别仅在免疫组织化学和/或超微结构研究后才变得明显。所有多形性RMS均显示出原始肌节，并表现出以下细胞骨架特征：波形蛋白（+）（18/18）、结蛋白（+）（14/18）、α-sr肌动蛋白（+）（18/18）和α-sm肌动蛋白（+）（5/18）。所有多形性LMS均表现出不同程度的平滑肌分化，表现为微丝的细胞质束和相关的致密体；它们的细胞骨架特征为波形蛋白（+）（14/14）、结蛋白（+）（7/14）、α-sr肌动蛋白（+）（0/14）和α-sm肌动蛋白（+）（8/14）。后者在所有中度分化的肿瘤中均有显示，但在低分化变体中缺失或仅局灶性表达。所有多形性MFH和LS均缺乏肌源性（骨骼肌或平滑肌）超微结构特征，仅表达波形蛋白。这项形态学和免疫组织化学联合研究表明：第一，这些多形性肉瘤仅通过组织学生长模式往往难以区分；因此，准确诊断需要使用所有这些技术进行研究。第二，多形性肌源性肉瘤仅限于成年人，在多形性肉瘤中并非罕见肿瘤：RMS（28%）、LMS（21%）、MFH（38%）和LS（13%）。第三，该研究定义了结蛋白阴性和α-sm肌动蛋白阳性的多形性RMS，以及结蛋白阴性和α-sm肌动蛋白阴性的多形性LMS。
