巨细胞血管母细胞瘤的临床病理学研究

Clinicopathologic study of giant cell angioblastoma

目的 探讨巨细胞血管母细胞瘤（GCAB）的临床病理学特征、影像学特点、免疫学表型及其鉴别诊断.方法 对1例15个月的男患儿发生于左侧胫骨、腓骨中上段的GCAB进行影像学、光镜观察和免疫组织化学标记.结果 X线片及CT片显示左侧胫骨、腓骨中上段骨病变,以胫骨改变明显,病变骨干明显增粗变形,髓腔内密度增高不均匀,骨皮质不规则增厚,骨内缘局部皮质缺损,邻近的软组织肿胀.镜下病变组织位于骨小梁之间,肿瘤组织呈结节状、梁索状或丛状聚集,瘤细胞卵圆形至梭形,散在胞质丰富、核仁明显的单核组织细胞样巨细胞及多核巨细胞;肿瘤组织内可辨认出数量不等的无或含有少量红细胞的微血管腔隙;部分瘤细胞呈同心圆样围绕在微血管腔隙周围并与周围间质胶原共同形成洋葱皮样外观.肿瘤间质疏松,其间为少量梭形纤维母细胞样细胞、星形间质细胞、单个核炎性细胞及散在的肥大细胞.免疫组织化学标记显示,卵圆形至梭形瘤细胞及巨细胞弥漫性强阳性表达波形蛋白;多数瘤细胞显著表达CD31及CD34,少数弱阳性表达第八因子相关抗原（FⅧRAg）;单核组织细胞样巨细胞及多核巨细胞强阳性表达CD68,偶见个别巨细胞胞质内局灶性表达FⅧRAg;肿瘤实质内小血管腔隙周围瘤细胞显著表达α-平滑肌肌动蛋白（SMA）,其他部分瘤细胞呈弱阳性表达.结论 GCAB是一种罕见的发生于婴幼儿并具有独特形态学特征及局部具有侵袭性行为的血管源性肿瘤,不仅可发生于皮肤、黏膜、皮下及深部软组织,还可发生于骨内.

Objective To study the clinicopathological features, imaging characteristics,immunophenotypes and differential diagnosis of giant cell angioblastoma （GCAB）. Methods A case of GCAB in the left middle-upper tibia and fibula was studied by light microscopy, X-ray and CT imaging,immunohistochemistry. Results X-ray and CT imaging showed a clearer lesion in the left middle-upper tibia than in the ipsilateral fibula with enlarged ostealleosis and increased inhomogeneously medullary cavity density, irregular thickening of cortical bone, local cortical default at the inner edge, soft tissue swelling around the abnormal bone. Histologically, tumor tissue was located between the bone trabeculae by nodular,linear and plexiform aggregates of oval-to-spindle cells, large mononucleate cells and multinucleate giant cells with prominent nucleoli and abundant granular eosinophilic cytoplasm. Some aggregates had uncentain amount of discernible lumens, either empty or containing few erythrocytes. A concentric arrangement of ovalto-spindle Cells around small-caliber vascular structures together with collagen fiber contributed to a so-called ＇onion-skin＇ arrangement. The background showed a loose mesenchymal stroma formed of some inconspicuous spindle-fibroblast-like cells, stellate-shape mesenchymal cells, a moderate mononuclear inflammatory cell infiltrate and scattered mast cells. Immunophenotype showed the tumor cells and giant cells strongly positive for vimentin. A good many oval-to-spindle cells stained markedly for CD31 and CD34, but weakly for FⅧ, while the giant cells are highlighted instead by CD68, occasionally, very few giant cells showed positive focally for FⅧ, a-SMA decorated notedly the cells surrounding the endothelium-like cells but weakly positive in some other tumor cells. Conclusion GCAB is a rare, locally infiltrative but slow growing neoplastic angiogenesis with unique morphological characteristics during infancy, which may occur not only in the skin, mucosa, subcutis and deep soft tissue but also in the bone.