Brain Tumor Pathology

, Volume 36, Issue 1, pp 20–26 | Cite as

A rapidly fatal intracranial anaplastic hemangiopericytoma with de-novo dedifferentiation: emphasis on diagnostic recognition, molecular confirmation and discussion on treatment dilemma

  • N. J. H. Tan
  • I. S. Y. Sun
  • S. W. Low
  • C. H. Kuick
  • K. T. E. Chang
  • C. L. TanEmail author
Case Report


Solitary fibrous tumors/ hemangiopericytomas (SFT/HPC) are mesenchymal tumors that share a common genetic aberration and very rarely undergo dedifferentiation. We report a unique case of an intracranial anaplastic SFT/HPC with de-novo dedifferentiation, which pursued a rapidly fatal clinical course in a 41-year-old lady. The dedifferentiated component comprised a focal area of glandular formation with epithelial immunophenotype acquisition. The distinct biphasic pattern of the tumor imparted great diagnostic challenges to the pathologists. An increased awareness of SFT/HPCs with a diverse morphologic spectrum or even a biphasic histologic pattern is essential in working up such cases. We first attempted gamma knife radiosurgery in treating a recurrent dedifferentiated SFT/HPC; unfortunately it was to no avail. Although it is now known that SFT/HPC is characterized by NAB2-STAT6 gene fusion, the unavailability of targeted therapy against this molecular signature still results in a treatment dilemma.


Solitary fibrous tumor Hemangiopericytoma STAT6 Intracranial Dedifferentiation Gamma knife 



Targeted next generation sequencing and RT-PCR of the tumor were funded by the VIVA-KKH Paediatric Brain and Solid Tumour Programme.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© The Japan Society of Brain Tumor Pathology 2019

Authors and Affiliations

  1. 1.Department of PathologyNational University Health SystemSingaporeSingapore
  2. 2.Division of Neurosurgery, Department of SurgeryNg Teng Fong General HospitalSingaporeSingapore
  3. 3.Department of Pathology and Laboratory MedicineKK Women’s and Children’s HospitalSingaporeSingapore

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