Hartel Paul H, Fanburg-Smith Julie C, Frazier Aletta A, Galvin Jeffrey R, Lichy Jack H, Shilo Konstantin, Franks Teri J
Department of Pulmonary and Mediastinal Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
Mod Pathol. 2007 Jul;20(7):760-9. doi: 10.1038/modpathol.3800795. Epub 2007 Apr 27.
Primary pulmonary and mediastinal synovial sarcoma is rare and poses a diagnostic challenge particularly when unusual histological features are present. We present 60 cases of primary pulmonary and mediastinal synovial sarcoma (29 male and 27 female subjects; mean age, 42 years) and compare our results with five prior series to better define unusual histological features. Clinically, patients with mediastinal synovial sarcoma were younger with a male gender bias. Radiologically, tumors were well delineated with distinctive magnetic resonance imaging features and little vascular enhancement. In all, 21/46 patients died of disease within 5 years. Histologically, all tumors had dense cellularity, interlacing fascicles, hyalinized stroma, and mast cell influx. Hemangiopericytoma-like vasculature (48/60), focal myxoid change (30/60), and entrapped pneumocytes (23/60) were seen. Calcification was not prevalent (10/60). Unusual histological features included Verocay body-like formations (7/60), vague rosettes (6/60), well-formed papillary structures (3/60), adenomatoid change (3/60), and rhabdoid morphology (2/60). Immunohistochemistry demonstrated expression of pancytokeratin (39/58), epithelial membrane antigen (29/53), cytokeratin 7 (26/40), cytokeratin 5/6 (5/7), calretinin (15/23), CD99 (19/23), bcl-2 (24/24), CD56 (11/11), S-100 (9/51), and smooth muscle actin (8/32). In total, 92% (36/39) of primary pulmonary and mediastinal synovial sarcomas studied were positive for t(x;18). In conclusion, our study confirms the clinical, histological, immunohistochemical, and molecular data from previous large series of primary pulmonary and mediastinal synovial sarcoma. Compared with soft tissue synovial sarcoma, primary pulmonary and mediastinal synovial sarcoma has less calcification, less obvious mast cell influx, and less radiologic vascularity, but similar magnetic resonance imaging features, percentage of poorly differentiated tumors, and number of t(x;18)-positive tumors. Awareness of focal unusual histology can prevent misdiagnosis particularly in t(x;18)-negative tumors.
原发性肺和纵隔滑膜肉瘤较为罕见，尤其当出现不寻常的组织学特征时，会带来诊断挑战。我们报告了60例原发性肺和纵隔滑膜肉瘤（男性29例，女性27例；平均年龄42岁），并将我们的结果与之前的5个系列研究进行比较，以更好地界定不寻常的组织学特征。临床上，纵隔滑膜肉瘤患者较年轻，且有男性偏倚。放射学上，肿瘤边界清晰，具有独特的磁共振成像特征，血管强化不明显。总共有21/46例患者在5年内死于该疾病。组织学上，所有肿瘤均有细胞密集、束状交错、玻璃样变的间质和肥大细胞浸润。可见血管外皮细胞瘤样血管（48/60）、局灶性黏液样改变（30/60）和陷入的肺上皮细胞（23/60）。钙化并不常见（10/60）。不寻常的组织学特征包括Verocay小体样结构（7/60）、模糊的菊形团（6/60）、良好形成的乳头结构（3/60）、腺瘤样改变（3/60）和横纹肌样形态（2/60）。免疫组化显示全细胞角蛋白（39/58）、上皮膜抗原（29/53）、细胞角蛋白7（26/40）、细胞角蛋白5/6（5/7）、钙视网膜蛋白（15/23）、CD99（19/23）、bcl-2（24/24）、CD56（11/11）、S-100（9/51）和平滑肌肌动蛋白（8/32）表达。总共，所研究的原发性肺和纵隔滑膜肉瘤中有92%（36/39）t(x;18)呈阳性。总之，我们的研究证实了之前关于原发性肺和纵隔滑膜肉瘤的大量系列研究中的临床、组织学、免疫组化和分子数据。与软组织滑膜肉瘤相比，原发性肺和纵隔滑膜肉瘤钙化较少、肥大细胞浸润不明显、放射学血管较少，但磁共振成像特征、低分化肿瘤百分比和t(x;18)阳性肿瘤数量相似。认识到局灶性不寻常组织学特征可防止误诊，尤其是在t(x;18)阴性肿瘤中。
