IMMUNOHISTOCHEMISTRY, CALDESMON

What this test checks

Detects h-caldesmon, a protein expressed in smooth muscle cells — used to confirm smooth muscle differentiation in tumours and distinguish smooth muscle tumours (leiomyoma, leiomyosarcoma) from other spindle cell tumours.

Why do people get this test?

Distinguishing smooth muscle tumours from other spindle cell lesions guides surgical and oncological management. Caldesmon is a specific smooth muscle marker that aids this classification.

When you should consider this test

• When classifying spindle cell soft tissue tumours
• When differentiating leiomyoma or leiomyosarcoma from other smooth muscle tumours
• As part of uterine or soft tissue tumour diagnostic panels

How to prepare

No preparation needed — performed on biopsy or surgical tissue.