ependymal rosette

Full Definition

An ependymal rosette is a specific histomorphological pattern characteristic of ependymal tumors, consisting of tumor cells arranged radially around a central lumen that resembles the central canal of the spinal cord or ventricular system. These rosettes are lined by cells with elongated nuclei arranged perpendicularly to the central space, often with cilia or microvilli projecting into the lumen. The presence of true ependymal rosettes is highly suggestive of ependymoma, though they are not present in all cases.

Usage

Usage note: Distinguish from pseudorosettes; indicates specific tumor type.

In Context

• "Multiple ependymal rosettes were identified, confirming the diagnosis of ependymoma." — Brain tumor pathology report
• "The tumor lacked true ependymal rosettes but showed perivascular pseudorosettes." — Differential diagnosis discussion