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Most primary central nervous system lymphomas (PCNSL) occurring in immunocompetent patients are diffuse large B-cell lymphomas (DLBCL), characterized by poor prognosis. An activated B-cell (ABC) origin of PCNSL has been postulated based on bcl-6 and MUM-1 expression by majority of these tumors. ABC DLBCL has been functionally subdivided using gene expression profiling and immunohistochemical analysis into STAT3-high and STAT-3 low subsets. A potentially crucial difference between STAT3-high and STAT3-low ABC DLBCL is in the expression of bcl-2 family members. STAT3-high cases are generally bcl-2 low and STAT3-low cases show higher expression of bcl-2. Further mechanisms such as activation of nuclear factor-kappa B (NF-κB) activation seem to be responsible for upregulation of bcl-2 in ABC subtype of DLBCL with an adverse outcome. As deregulation of STAT-3 pathway is known to play a critical role in ABC DLBCL and majority of the PCNSL are of the ABC subtype we studied the immunohistochemical expression of STAT-3 proteins in PCNSL along with other traditional markers (CD10, bcl-6, MUM-1 and bcl-2) in 17 cases of PCNSL occurring in immunocompetent patients. Despite lack of STAT3 expression in all our cases, majority (70%) of the patients with bcl-2 positive PCNSL had an adverse outcome similar to that reported in systemic lymphomas of ABC subtype. Based on our observations we propose that PCNSL represents a distinct subset of ABC diffuse large B-cell lymphomas with low STAT3 expression and perhaps mechanisms other than interaction of STAT-3 and NF-κB pathways may play a role in upregulation of bcl-2 in PCNSL. To the best of our knowledge expression of STAT-3 protein in PCNSL which represents a distinct anatomical subset of ABC DLBCL with a dismal prognosis has not been studied before.

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Metastasis of systemic malignancies to primary intracranial tumors is uncommon. Occasional reports have seen meningiomas as hosts for metastatic carcinomas, especially from lung and breast. We report a case of a 46 year‐old woman who presented with headache and a rapidly enlarging right frontal dural‐based lesion. She had been diagnosed at birth with bilateral retinoblastoma, treated with left enucleation and Co‐60 radiation to the right eye. She was subsequently diagnosed with papillary thyroid carcinoma in 2000 and invasive ductal carcinoma with solitary sentinel lymph node metastasis in 2004. In 1997, she underwent the first of three resections for a meningioma of the right sphenoid wing and orbit; gamma knife radiosurgery was utilized for control of residual tumor. Serial imaging studies revealed growth of two additional presumptive meningiomas in parasellar and right frontal locations, the later showing recent rapid enlargement in 2007 necessitating surgical intervention. Microscopic and immunohistochemical assessment of this lesion revealed a WHO grade I meningioma harboring metastatic invasive ductal carcinoma. Further work‐up revealed extensive metastasis to axial skeleton, liver and spleen. This case emphasizes the need for surgical evaluation of rapidly enlarging dural‐based lesions in patients with systemic malignancies as these lesions may represent meningiomas, metastases, or both.