The histopathological studies demonstrated the presence of a hemangiopericytoma-like tumor with adipocytary component; the immunohistochemical studies demonstrated the presence of cluster of differentiation 34 (CD34), while human melanoma black (HMB45) staining was negative.
We present a 53 year old woman initially diagnosed as hemangiopericytoma in the posterior fossa on the right side post excision with immunohistochemistry staining for CD34 being positive.
Diagnoses were confirmed by pathology which reported spindle cell neoplasm staining positively for VEGF, NSE, factor XIIIa, S-100 protein, and CD34, and negative for actin, desmin, CD31, and pankeratin, consistent with hemangiopericytoma.
In summary, when encountering a bland spindle cell neoplasm with classic hemangiopericytoma-like blood vessels, it is prudent to consider a diagnosis of LGFMS besides solitary fibrous tumor--particularly in the absence of CD34 immunoreactivity as it may be a rare, mimicking variant of LGFMS.