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