韧带样型纤维瘤病的临床病理学及遗传学研究

目的研究韧带样型纤维瘤病的临床病理学和遗传学特点,探讨用荧光原位杂交的方法在石蜡包埋组织中检测8号染色体三体的可行性。方法分析96例韧带样型纤维瘤病的临床资料,对69例进行组织学形态和免疫学表型分析（免疫组织化学EnVision两步法,抗体包括波形蛋白、结蛋白、α-平滑肌肌动蛋白、B—catenin、CD34、CD117、S-100）、对2例行电镜观察,采用荧光原位杂交检测20例石蜡包埋组织中的8号染色体三体。结果96例病例中男20例,女76例,年龄范围8～86岁,平均35．3岁。腹部以外部位的病变44例,腹壁和盆腔的病变28例,腹腔内病变23例,其中2例与Gardner综合征伴发。病变直径在0．6～24．0cm之间,平均8．4cm,结节或者条索状肿块,质地韧,切面粗糙。显微镜下形态较一致的梭形细胞分布于大量增生的胶原纤维间质内,梭形的纤维母细胞和肌纤维母细胞常排列成束状,胞质界限不清,细胞异形性不明显。透射电镜下,纤维母细胞有丰富的粗面内质网和发达的高尔基复合体,肌纤维母细胞还可以看到应力纤维、纤维连接复合体、中间连接和缝隙连接。所有病例均表达波形蛋白,部分病例还表达结蛋白和α-平滑肌肌动蛋白。B—catenin胞质和核的异位表达阳性率为47．8％（33／69）。8号染色体三体阳性率为30．0％（6／20）,原发病例中8号染色体三体阳性率为1／12,显著低于复发病例的5／8。结论韧带样型纤维瘤病是主要发生于年轻女性的中间型肿瘤。它主要由纤维母细胞和肌纤维母细胞构成,而肌纤维母细胞有应力纤维、纤维连接复合体等特征性结构。可用荧光原位杂交方法在石蜡组织中检测8号染色体三体,其可能为韧带样型纤维瘤病的复发预测因子,并界定某种高复发风险亚型。

Clinicopathologic and genetic studies of desmoid-type fibromatosis

OBJECTIVE: To study the clinicopathological and genetic features of desmoid-type fibromatosis, and to investigate the feasibility of detecting trisomy 8 in formalin fixed, paraffin embedded (FFPE) tissue by fluorescence in-situ hybridization (FISH). METHODS: A total of 96 cases were included in this study. All patients had clinical information. Histopathologic and immunohistochemical evaluations were available in 69 cases, and ultrastructural evaluation was done in 2 cases of desmoid-type fibromatosis. FFPE tissue sections were available in 20 tumors for the trisomy 8 detection by FISH. RESULTS: There were 20 male and 76 female patients with ages ranging from 8 to 86 years (mean 35.3 years). Clinically, there were 44 extra-abdominal tumors, 28 abdominal wall tumors and 23 intra-abdominal lesions mostly involving the mesentery. Most cases presented with nodular or funicular masses with white firm cut surfaces, measuring 0.6 to 24.0 cm (mean 8.4 cm) in size. Histologically, desmoid-type fibromatoses showed longitudinal fascicles of spindle fibroblasts and myofibroblasts in a predominantly collagenous background. The tumor cells stained positive for vimentin, alpha-smooth muscle actin, desmin, and beta-catenin (47.8%, 33/69). Ultrastructurally, most tumor cells had features of fibroblasts, including rich endoplasmic reticulum and Golgi apparatus. Some tumor cells were myofibroblast-like cells exhibiting intercellular junctions, fibronexous junctions and stress fibers. Trisomy 8 was detected in 6 of 20 cases of desmoid-type fibromatosis including 5 of the 8 recurrent tumors but only one of the 12 primary tumors. The latter tumor also recurred three years later. CONCLUSIONS: Desmoid-type fibromatosis is an intermediate (locally aggressive) tumor that occurs predominantly in young females. The lesion consists of fibroblasts and myofibroblasts with the latter showing characteristic features including stress fibers and fibronexous junctions. Trisomy 8 can be detected in FFPE tissue by FISH, and its presence serves as a useful predictor of tumor recurrence and may define a subtype of desmoid-type fibromatosis with high recurrence rate.