Department of Surgical Pathology, Nishi-Kobe Medical Center, Kobe, Japan.
Am J Surg Pathol. 2010 Nov;34(11):1622-9. doi: 10.1097/PAS.0b013e3181f5974f.
PEComas other than angiomyolipoma, lymphangioleiomyomatosis, and clear cell sugar tumor of the lung are relatively rare, and PEComas presenting in bone are especially rare. To further characterize their clinicopathologic features, 6 cases of PEComa which first presented in bone were retrieved from the authors' consult and surgical pathology files, including both primary and metastatic lesions. Four patients were female and 2 patients were male. The age at diagnosis ranged from 35 to 71 years, with a mean of 51.5 years. As for the 3 cases known definitely to have arisen in bone, the primary sites were right tibia in 2 cases and thoracic vertebra in 1 case. In the 2 cases, presenting in scapula and femur respectively, the primary sites could not be determined with certainty. In 1 case, the lesion was first found in humerus, but the primary tumor proved to be located in the uterus. Histologically, all the tumors were composed of both epithelioid and spindle cells, showing a nested pattern with elaborate vasculature. The characteristic thin walled vessels around which tumor cells were arranged tightly, or in a radiating fashion were seen in all cases. Two or more worrisome features (tumor size >5 cm, infiltrative growth pattern, high nuclear grade, high cellularity, necrosis, and mitotic activity >1/50 HPF) were identified in 4 cases, of which 2 were primary bone tumors; these cases were classified as "malignant" histologically. We conclude that both the primary and metastatic PEComas can present in bone, although both are rare. Combining our findings with the few earlier published reports, it may be suggested that primary PEComa of bone tends to involve lower extremities (5/7 cases). Histologically, they show similar cytomorphology, nested architecture, and characteristic vessels as PEComas at other sites. In addition, a significant subset of the primary bone lesions seem to be malignant.
除了血管平滑肌脂肪瘤、淋巴管平滑肌瘤病和肺透明细胞糖瘤外，PEComa 较为罕见，而原发于骨的 PEComa 则更为罕见。为了进一步描述其临床病理特征，我们从作者的会诊和外科病理档案中检索了 6 例最初发生于骨的 PEComa 病例，包括原发性和转移性病变。4 例为女性，2 例为男性。诊断时的年龄为 35-71 岁，平均年龄为 51.5 岁。在 3 例明确起源于骨的病例中，原发性肿瘤位于 2 例患者的右胫骨和 1 例患者的胸椎体。在分别发生于肩胛骨和股骨的 2 例患者中，原发性肿瘤无法明确。在 1 例患者中，病变最初发生于肱骨，但原发性肿瘤位于子宫。组织学上，所有肿瘤均由上皮样细胞和梭形细胞组成，呈巢状排列，伴有精心构建的血管。所有病例均可见特征性的薄壁血管，肿瘤细胞围绕血管排列紧密，或呈放射状排列。在 4 例病例中发现了 2 个或更多令人担忧的特征（肿瘤大小>5cm、浸润性生长模式、高级别核级、高细胞密度、坏死和有丝分裂活性>1/50 HPF），其中 2 例为原发性骨肿瘤；这些病例在组织学上被归类为“恶性”。我们的结论是，原发性和转移性 PEComa 均可发生于骨，尽管均较为罕见。将我们的发现与之前发表的少数报道相结合，可能提示原发性骨 PEComa 倾向于累及下肢（7 例中的 5 例）。组织学上，它们显示出与其他部位的 PEComa 相似的细胞形态学、巢状结构和特征性血管。此外，原发性骨病变中有相当一部分似乎为恶性。
