Lucas D R, Fletcher C D, Adsay N V, Zalupski M M
Department of Pathology, Wayne State University School of Medicine, Harper Hopspital and Karmanos Cancer Center, Detroit, MI 48201, USA.
Histopathology. 1999 Sep;35(3):201-8. doi: 10.1046/j.1365-2559.1999.00735.x.
Extraskeletal myxoid chondrosarcoma is typically a low-to-intermediate grade sarcoma that is associated with a prolonged clinical course. High-grade forms are rare and not well characterized. In this series we report the clinicopathological, immunohistochemical and ultrastructural findings in four cases of high-grade extraskeletal myxoid chondrosarcoma.
The patients were three men and one woman (ages 34-73 years) with tumours located in the thigh (two cases), paraspinal soft tissue and perineum. Three patients had metastases, one at 12 weeks, one at 10 months, and one at presentation of recurrent tumour. In the latter case the original tumour was low grade and became high grade when it recurred 3.5 years later. All three patients died of disease. One patient was lost to follow-up. The most striking histological feature in all four tumours was the presence of numerous large epithelioid cells. These cells were arranged in cords within myxoid matrix and in sheets devoid of matrix. Two tumours had areas of conventional extraskeletal myxoid chondrosarcoma intermixed with the high-grade areas. One tumour showed transition to high-grade spindle cell sarcoma. One tumour had cells with rhabdoid features. Immunohistochemically, two tumours focally expressed S100 protein, and one focally expressed EMA. All were negative with cytokeratin, desmin, smooth muscle actin, HMB45, CD31 and CD34. Ultrastructural features in three cases were compatible with chondrosarcoma; one tumour had aggregates of microtubules within rough endoplasmic reticulum, a characteristic feature of this tumour.
High-grade extraskeletal myxoid chondrosaroma is a rare and aggressive soft tissue sarcoma, and should be included in the differential diagnosis of other epithelioid malignancies.
骨外黏液样软骨肉瘤通常是一种低至中级别的肉瘤，临床病程较长。高级别形式罕见且特征不明。在本系列研究中，我们报告了4例高级别骨外黏液样软骨肉瘤的临床病理、免疫组化及超微结构特征。
患者包括3名男性和1名女性（年龄34 - 73岁），肿瘤分别位于大腿（2例）、脊柱旁软组织和会阴。3例患者发生转移，1例在12周时转移，1例在10个月时转移，1例在复发性肿瘤出现时转移。在最后1例中，原发肿瘤为低级别，3.5年后复发时变为高级别。所有3例患者均死于疾病。1例患者失访。所有4例肿瘤最显著的组织学特征是存在大量大的上皮样细胞。这些细胞在黏液样基质内呈条索状排列，在无基质的片状区域中排列。2例肿瘤有传统骨外黏液样软骨肉瘤区域与高级别区域混合存在。1例肿瘤显示向高级别梭形细胞肉瘤转变。1例肿瘤有具有横纹肌样特征的细胞。免疫组化方面，2例肿瘤局灶性表达S100蛋白，1例局灶性表达EMA。所有病例细胞角蛋白、结蛋白、平滑肌肌动蛋白、HMB45、CD31和CD34均为阴性。3例的超微结构特征与软骨肉瘤相符；1例肿瘤在粗面内质网内有微管聚集，这是该肿瘤的特征性表现。
高级别骨外黏液样软骨肉瘤是一种罕见且侵袭性强的软组织肉瘤，应列入其他上皮样恶性肿瘤的鉴别诊断。
