Presentation
HIV +ve (CD 4+ count, HAART, etc. unknown).
Patient Data
Enhancing left middle fossa mass with wide dural attachment.
Extra-axial mass with low T2 signal and vivid contrast enhancement.
Case Discussion
The patient went on to have a craniotomy and resection.
Histology
Microscopic Description:
Sections show a spindle cell neoplasm. It is composed of irregularly arranged fascicles of spindle cells. Areas of microcystic change are noted. Occasional areas of necrosis are present. There are occasional mitotic figures.
Immunohistochemistry shows positive staining for smooth muscle actin. The tumor is negative for CD34, CD31, GFAP and S-100 protein. The tumor is positive for caldesmon.
Electron microscopy shows the tumor is composed of spindle cells with intermediate filaments. Many of these intermediate filaments undergo focal densifications, characteristic of smooth muscle cells. However, in addition, many of these tumor cells show fibronexus junctions, such as have been described in myofibroblasts.
FINAL DIAGNOSIS
This tumor was reviewed by a pathologist with expertise in soft tissue tumors, who felt that this is a malignant tumor; more precisely, a leiomyosarcoma. He noted that such lesions have been described in patients infected with HIV and these are related to Epstein-Barr virus infection. He did immunohistochemical stains and these showed strong positive staining for caldesmon, a low MIB-1 index and strong positive staining throughout the lesion for Epstein-Barr virus in situ hybridization. There was negative staining for HHV8. These features are in keeping with a leiomyosarcoma associated with Epstein-Barr virus infection in an immune-suppressed patient.
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