‘Papillary’ solitary fibrous tumor/hemangiopericytoma with nuclear STAT6 expression and NAB2-STAT6 fusion

• Published in: Brain tumor pathology Vol. 33; no. 2; pp. 151 - 156
• Main Authors: Ishizawa, Keisuke, Tsukamoto, Yoshitane, Ikeda, Shunsuke, Suzuki, Tomonari, Homma, Taku, Mishima, Kazuhiko, Nishikawa, Ryo, Sasaki, Atsushi
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.04.2016; Springer Nature B.V
• Subjects: Aged, 80 and over; Antigens; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Brain Neoplasms - blood supply; Brain Neoplasms - diagnosis; Brain Neoplasms - genetics; Brain Neoplasms - pathology; Cancer Research; Case Report; Female; Gene Expression - genetics; Gene Fusion - genetics; Genes; Hemangiopericytoma - blood supply; Hemangiopericytoma - diagnosis; Hemangiopericytoma - genetics; Hemangiopericytoma - pathology; Humans; Immunohistochemistry; Magnetic Resonance Imaging; Medicine; Medicine & Public Health; Neoplasms, Multiple Primary - genetics; Neoplasms, Multiple Primary - pathology; Neuroimaging; Neurology; Neurosurgery; Oncology; Pathology; Repressor Proteins - genetics; Repressor Proteins - metabolism; Solitary Fibrous Tumors - blood supply; Solitary Fibrous Tumors - diagnosis; Solitary Fibrous Tumors - genetics; Solitary Fibrous Tumors - pathology; STAT6 Transcription Factor - genetics; STAT6 Transcription Factor - metabolism; Tomography; Tomography, X-Ray Computed; fusion; Papillary structure; Hemangiopericytoma; Solitary fibrous tumor; -; STAT6-immunohistochemistry; NAB2-STAT6 fusion
• ISSN: 1433-7398; 1861-387X
• DOI: 10.1007/s10014-015-0247-z

This report describes clinicopathological findings, including genetic data of STAT6, in a solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) of the central nervous system in an 83-year-old woman with a bulge in the left forehead. She noticed it about 5 months before, and it had grown rapidly for the past 1 month. Neuroradiological studies disclosed a well-demarcated tumor that accompanied the destruction of the skull. The excised tumor showed a prominent papillary structure, where atypical cells were compactly arranged along the fibrovascular core (‘pseudopapillary’). There was rich vasculature, some of which resembled ‘staghorn’ vessels. Mitotic figures were occasionally found. Whorls, psammoma bodies, or intra-nuclear pseudoinclusions were not identified. By immunohistochemistry, CD34 was strongly positive in the tumor cells, and STAT6 was localized in their nuclei. By reverse transcription-polymerase chain reaction (RT-PCR), an NAB2 - STAT6 fusion gene, NAB2 exon6 - STAT6 exon17 , was detected, establishing a definite diagnosis of SFT/HPC. ‘Papillary’ SFT/HPC needs to be recognized as a possible morphological variant of SFT/HPC, and should be borne in mind in its diagnostic practice.