collar-button configuration
A distinctive tumor morphology characterized by a narrow neck connecting intraocular and extraocular tumor components through the scleral wall.
Full Definition
Collar-button configuration describes a characteristic tumor growth pattern where an intraocular mass extends through the scleral wall via a relatively narrow opening, creating a dumbbell or collar-button shaped lesion with both intraocular and extraocular components. This configuration is most commonly observed in uveal melanomas that have achieved extrascleral extension, though it can occur with other tumor types. The narrow scleral opening acts as a constriction point, creating the distinctive appearance on imaging studies including ultrasound, CT, and MRI. Recognition of this configuration is crucial as it indicates advanced local disease (T4 classification) and may influence surgical planning, particularly if enucleation or exenteration is being considered.
Usage
Usage note: Indicates advanced local disease; document both intraocular and extraocular components.
In Context
- "MRI demonstrated a collar-button configuration with significant orbital extension requiring multidisciplinary surgical planning." — Imaging interpretation
- "The collar-button configuration indicated T4 staging and influenced the decision for orbital exenteration rather than globe-sparing therapy." — Staging assessment