Guillou L, Wadden C, Coindre J M, Krausz T, Fletcher C D
Institut Universitaire de Pathologie, Lausanne, Switzerland.
Am J Surg Pathol. 1997 Feb;21(2):130-46. doi: 10.1097/00000478-199702000-00002.
Eighteen examples of an unusual malignant soft-tissue neoplasm, the morphology of which ranged from that of "atypical" epithelioid sarcoma to that of a rhabdoid tumor or undifferentiated carcinoma (with transitional forms) are described. Patients included 11 males and seven females; their median age was 35.5 years with most patients aged 20 to 40 years. Development of a mass was the main presenting symptom. Six tumors developed in the pelvis and perineal region, four in the pubic region and vulva, three in the buttocks, one in the deep soft tissues of the left hip, one on the penis, one in left forearm, one in left axilla, and one on the occiput. Tumor size ranged from 1 to 20 cm (median, 4 cm). On microscopic examination, the tumor cells invaded the subcutaneous or deep soft tissues, had prominent epithelioid or rhabdoid features, had marked cytologic atypia, and grew in a multinodular pattern in half of the cases. Areas of necrosis were often seen. A granuloma-like pattern reminiscent of that observed in classic epithelioid sarcoma was observed in only two cases. Immunohistochemically, positivity for cytokeratin, epithelial membrane antigen, and vimentin was seen in all but one of the cases. Of 16 cases, 10 and eight tumors reacted with desmin and CD34, respectively; five of 15 reacted at least focally with smooth-muscle actin, whereas three of 13 and one of 10 reacted for HMB-45 and carcinoembryonic antigen, respectively. S-100 protein and CD31 yielded negative results. Seven tumors were investigated at the ultrastructural level, four of which showed prominent intracytoplasmic intermediate filament aggregates, often accumulating into paranuclear whorls, which is in keeping with the rhabdoid phenotype. Five tumors showed features of epithelial differentiation (i.e., tonofilament-like structures or desmosomes or both), whereas one tumor displayed features of myofibroblastic differentiation. Differential diagnoses include mainly conventional epithelioid sarcoma, extrarenal malignant rhabdoid tumor, epithelioid malignant peripheral nerve sheath tumor, melanoma, rhabdomyosarcoma, and undifferentiated carcinoma. Follow-up information on 14 patients (range, 4 months to 8 years; median, 19 months) revealed local recurrence in one case and metastatic dissemination in six patients, leading to death in five. In our opinion, the above-described neoplasms represent a usually "proximal-type" of epithelioid sarcoma. In contrast to the conventional, "distal-type" epithelioid sarcoma, the proximal variant is characterized by a predominantly large-cell, epithelioid cytomorphology, marked cytologic atypia, frequent occurrence of rhabdoid features, and lack of a granuloma-like pattern in most cases. It appears to be somewhat more aggressive (or at least metastasizes earlier) than usual epithelioid sarcoma.
本文描述了18例罕见的恶性软组织肿瘤，其形态从“非典型”上皮样肉瘤到横纹肌样肿瘤或未分化癌（伴有过渡形式）不等。患者包括11名男性和7名女性；中位年龄为35.5岁，大多数患者年龄在20至40岁之间。肿块形成是主要的首发症状。6例肿瘤发生于骨盆和会阴区，4例在耻骨区和外阴，3例在臀部，1例在左髋部深部软组织，1例在阴茎，1例在左前臂，1例在左腋窝，1例在枕部。肿瘤大小为1至20 cm（中位值4 cm）。显微镜检查显示，肿瘤细胞侵犯皮下或深部软组织，具有显著的上皮样或横纹肌样特征，细胞异型性明显，半数病例呈多结节状生长。常可见坏死区域。仅2例观察到类似经典上皮样肉瘤中所见的肉芽肿样模式。免疫组化显示，除1例病例外，其余所有病例的细胞角蛋白、上皮膜抗原和波形蛋白均呈阳性。16例病例中，分别有10例和8例肿瘤对结蛋白和CD34呈反应；15例中有5例至少局灶性地对平滑肌肌动蛋白呈反应，而13例中有3例、10例中有1例分别对HMB-45和癌胚抗原呈反应。S-100蛋白和CD31检测结果为阴性。7例肿瘤进行了超微结构检查，其中4例显示胞质内有显著的中间丝聚集物，常聚集成核旁涡旋，这与横纹肌样表型相符。5例肿瘤表现出上皮分化特征（即张力丝样结构或桥粒或两者皆有），而1例肿瘤表现出肌成纤维细胞分化特征。鉴别诊断主要包括传统上皮样肉瘤、肾外恶性横纹肌样肿瘤、上皮样恶性外周神经鞘瘤、黑色素瘤、横纹肌肉瘤和未分化癌。14例患者的随访信息（范围为4个月至8年；中位值为19个月）显示，1例局部复发，6例发生远处转移，5例死亡。我们认为，上述肿瘤代表了一种通常为“近端型”的上皮样肉瘤。与传统的“远端型”上皮样肉瘤不同，近端型变体的特征是主要为大细胞、上皮样细胞形态，细胞异型性明显，横纹肌样特征常见，且大多数病例缺乏肉芽肿样模式。它似乎比普通上皮样肉瘤更具侵袭性（或至少转移更早）。
