Pathology
The sections show dense, fibrous tissue with a central hypercellular region containing a dense lymphoplasmacytic infiltrate admixed with larger cells with irregular pale ovoid nuclei and abundant clear cytoplasm. Occasional binucleate forms and intranuclear inclusions can be seen. Russel bodies are noted. Mitotic count is <1 per 10 HPF. There is no sheetlike growth, nucleoli prominence, or necrosis evidence.
Immunoperoxidase demonstrates strong membranous staining with SSTR2a *. EMA is negative. CD3 and CD20 highlight background lymphocytes.
Final diagnosis: lymphoplasmacyte-rich meningioma (CNS WHO grade 1).
Pathology courtesy of Dr Samuel Roberts-Thomson.
Note: * Somatostatin receptors (SSTR), especially SSTR2, are reliable markers for meningiomas 1.