Department of Pathology, Laboratory Medicine Center, Cancer Center, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China.
Department of Pathology, Peking University Health Science Centre, Beijing, China.
Am J Clin Pathol. 2022 Jul 1;158(1):35-46. doi: 10.1093/ajcp/aqab211.
Solitary fibrous tumor (SFT) harboring extensive epithelial inclusions is rare and can stimulate a biphasic neoplasm composed of epithelial and stromal elements.
Three cases of SFT with extensive epithelial inclusions were retrieved. H&E stain, immunohistochemical stain, and targeted next-generation sequencing were performed.
There were two male patients and one female patient aged 54, 32, and 68 years. All tumors were located in abdominopelvic sites involving the kidney (case 1), omentum (case 2), and prostate (case 3), respectively. Microscopically, all tumors were circumscribed and composed of a background of SFT admixed with randomly embedded glands or cysts, organizing sometimes in a phyllodes-like architecture. The covered epithelium displayed a range of morphologies from simple cystic to stratified and to complex papillary proliferation. Immunohistochemically, both STAT6 and CD34 were expressed in the spindle cells but not in the epithelial inclusions. RNA sequencing revealed fusions involving NAB2~STAT6 in all cases. DNA sequencing demonstrated TERT c.-124C>T mutation in case 1. Prognostic stratification scores were intermediate in case 1 and low in cases 2 and 3.
SFT with extensive epithelial inclusions represents a rare but potentially underrecognized variant of SFT and shows compatible molecular features with conventional SFT.
富含广泛上皮成分的孤立性纤维瘤（SFT）罕见，可刺激由上皮和间质成分组成的双相性肿瘤。
我们回顾了 3 例富含广泛上皮成分的 SFT 病例。进行了 H&E 染色、免疫组织化学染色和靶向下一代测序。
3 例患者分别为 54 岁男性、32 岁男性和 68 岁女性。所有肿瘤均位于腹盆腔部位，累及肾脏（例 1）、网膜（例 2）和前列腺（例 3）。镜下，所有肿瘤均边界清楚，由 SFT 背景混合随机嵌入的腺体或囊肿组成，有时呈叶状样结构排列。被覆上皮的形态范围从单纯性囊肿到复层状，再到复杂的乳头状增生。免疫组织化学染色显示，STAT6 和 CD34 在梭形细胞中均有表达，但不在上皮成分中表达。RNA 测序显示所有病例均存在 NAB2~STAT6 融合。DNA 测序显示例 1 存在 TERT c.-124C>T 突变。例 1 的预后分层评分为中危，例 2 和例 3 为低危。
富含广泛上皮成分的 SFT 是一种罕见但可能被低估的 SFT 变体，具有与传统 SFT 相符的分子特征。
