Secretory meningioma with KLF4 K409Q mutation in collision with glioma

The simultaneous occurrence of two primary intracranial tumors is a rare event, especially if unrelated to radiotherapy or genetic disorders. We present two patients, both with two primary intracranial tumors simultaneously present at adjacent sites, in order to explore a possible mechanism of synchronous tumor formation.

We performed a molecular analysis of the K409Q mutation of the KLF4 gene, in addition to conventional immunohistochemistry.

Preoperative gadolinium-enhanced magnetic resonance imaging revealed a necrotic mass with an irregular ring-like enhancement adjacent to a frontal meningioma in patient 1, and an infiltrative non-enhancing glial tumor with no evidence of another tumor in patient 2. Postoperative histological examination revealed the presence of two distinct tumors in both cases: secretory meningioma and glioblastoma in patient 1 and secretory meningioma and anaplastic astrocytoma in patient 2. Secretory meningiomas both showed the KLF4 K409Q mutation, while none of the glial tumors had it.

To our knowledge, these are the first two cases reported of the simultaneous occurrence of secretory meningiomas with mutation of KLF4 in collision with a glioblastoma and an anaplastic astrocytoma, respectively. These collision tumors presumably have different molecular origins.