Presentation
Incidental occipital skull finding on CT for further investigation.
Patient Data
The outer table of the left occipital bone is thinned and the defect filled with high T2 signal material. Unfortunately the patient is allergic to contrast.
No inner table breach or meningeal abnormality.
Case Discussion
The patient went on to have surgery.
Histology
MICROSCOPIC DESCRIPTION: Sections show subcutaneous tissue containing a non-encapsulated ill defined spindle cell tumor composed of short fascicles. Tumor cells contain scant eosinophilic cytoplasm and wavy nuclei. Scattered mast cells are present. No epidermis is present. No atypia or mitoses are seen. There is no evidence of malignancy. Immunohistochemically tumor cells stain: S100+, CD34-, SMA- and Factor XIIIa-.
FINAL DIAGNOSIS: Benign nerve sheath tumor.