浅表宫颈阴道肌纤维母细胞瘤的临床病理学观察

Superficial cervicovaginal myofibroblastoma:case report with a review of the literature

目的探讨浅表宫颈阴道肌纤维母细胞瘤(superficialcervicovaginalmyofibroblastoma,SCVM)的临床病理学特点、免疫表型、超微结构和鉴别诊断。方法对1例发生于阴道和穹隆部的SCVM进行组织学观察、免疫组化标记和电镜检测。结果患者,63岁,因阴道分泌物增多1个月并扪及有肿物自阴道口突出就诊。妇检于阴道右前壁上方和阴道左上穹隆处可见直径分别为3cm和1.1cm的带蒂肿块。大体上,肿块均呈椭圆形,边界清晰。低倍镜下,肿瘤位于黏膜下,呈卵圆形,与周围组织分界清楚,但无包膜。位于肿瘤浅表或周边区域内的瘤细胞成分相对稀疏,间质呈黏液样或水肿样;位于中心区域内的瘤细胞相对密集,细胞之间可见纤细、致密的胶原纤维。高倍镜下,瘤细胞由形态基本一致、淡嗜伊红染的梭形细胞和星状细胞组成,瘤细胞无明显的异型性,核分裂象罕见(<2个/50HPF)。在瘤细胞稀疏、间质呈黏液样的区域内,瘤细胞多呈短条束状、网格状、花边状或筛孔状排列,或排列紊乱,偶见多核性细胞;在瘤细胞密集、间质富含胶原纤维的区域内,瘤细胞多呈条束状或波浪状排列,并与胶原纤维的走向一致。肿瘤内含有散在分布的薄壁血管,间质内可见丰富的肥大细胞,并见少量的慢性炎细胞浸润。免疫组化标记显示,瘤细胞强阳性表达vimentin、desmin、ER和PR,灶性表达CD34,不表达EMA、αSMA、MSA、hcaldesmon、NF、S100蛋白、CD57和calretinin等。电镜检测显示瘤细胞部分具肌纤维母细胞分化。结论SCVM是一种起自于女性阴道和宫颈黏膜下浅表基质的良性间叶性肿瘤,其独特的组织学形态提示SCVM可被视为一种新的病种。免疫表型和超微结构均显示瘤细胞具肌纤维母细胞分化。SCVM应注意与同样好发于女性下生殖道的一些间叶性病变相鉴别。

Purpose To study the clinicopathoiogical, immunohistochemical and ultrastructural features of superficial cervicovaginal myofiblastoma （ SCVM）, with emphasis on differential diagnosis. Methods One case of SCVM arising in the vagina and vaginal fornix was evaluated by light microscopy, immunohistochemistry and electron microscopy. Results A 63-year-old female complained of increasing vaginal discharge and noticed a mass that prolapsed out of the vagina for a period of one month. Examination revealed two pedunculated tumors located in the right uplateral vagina and the left vaginal fornix respectively, measuring 3cm and 1.1cm each in maximum diameter. Grossly, both ovoid tumors were well circumscribed, with glistening appearance on cut surface. On lower magnification, the tumors were located in the lamina propria of the vagina and well demarcated from surrounding tissues but unencapsulated. The superficial and peripheral areas of the tumor were less cellular and the stroma appeared myxoid or edematous, whereas the central portions were more cellular and the stroma contained abundant collagen fibers. On high magnification, they were composed of uniform pale eosinophilic spindle and stellate-shaped cells, with no evident atypia and rare mitotic figures （ 〈2/50 HPF）. In less cellular areas,the tumor cells were arranged mostly in short fascicles,delicate networks,or assumed a lacelike or sievelike growth pattern, or in a random fashion, whereas in more cellular areas, they were arranged in slender fascicles or wavy bundles with their long axes paralleling the slender fibers. The tumor contained scattered thin-walled vessels. Mast cells were readily encountered in the stroma. The tumor cells were showed strong immunostaining with vimentin, desmin, ER and PR, and focal reactivity with CD34. Electron microscopic study showed partial myofibroblastic differentiation. Conclusions SCVM is a benign mesenchymal tumor arising within the superficial stroma of the vagina and cervix. Although rare, the distinctive morphology of SCVM merits to be classified as a new entity. The immunohistochemical and uhrastructural studies suggested a myofibroblastic differentiation. SCVM should be distinguished from a group of mesenchymal lesions that occur specifically in the lower female genital tract.