Clinicopathological characteristics of nodular fasciitis of the breast
FU Xingning
HAN Guiyan
PAN Aifeng
HAN Kai
SUN Wenzheng
YANG Maiqing
ZHANG Yunxiang
ZHENG Yuanhang
ZHANG Hengming
Abstract：Objective To investigate the clinicopathological characteristics of nodular fasciitis of the breast(NFB).Methods The clinical data of 11 cases of NFB were retrospectively analyzed to summarize its pathological features,immunophenotype,and molecular genetic characteristics,with review of relevant literature.Results There were all female,aged 18-54 years(median 38.5 years).Diameter of tumors was from 0.5 cm-3.2 cm(median 1.6 cm).Microscopically,the tumors exhibited an infiltrative growth pattern with ill-defined borders.The spindle-shaped myofibroblasts were arranged in fascicular or haphazard patterns,displaying bland cytologic features with small nucleoli.Mitotic figures were readily identifiable.The stroma showed variable degrees of collagenization to myxoid change,accompanied by lymphocytic infiltration and erythrocyte extravasation.Immunophenotypically,the spindle cells expressed SMA,vimentin and CD10 but were negative for ER,PR,CK,EMA,S-100,CD34,CD117,DOG1,BCL-2,ALK,and STAT6.Multinucleated giant cells expressed CD68.Fluorescence in situ hybridization testing for the USP6 gene revealed the gene rearrangements in all cases.Conclusion NFB is rare,and it needs to be differentiated from other spindle cell lesions of the breast.Molecular genetic detection for USP6 gene rearrangement can facilitate the diagnosis.For treatment,NFB requires local excision.
Keywords：Nodular fasciitisUnusual sitesClinicopathological featuresGene rearrangement
Publication Date：2026-01-28
Online Publishing Date：2026-03-31(First online date of this platform, not the publication date of the document)
Pages：5( 30-34 )