IPMs are diagnosed by examination of the tissue by a pathologist.

They have a rim of peripheral lymphoid tissue (remnant of a lymph node) and consist of spindle cells with nuclear palisading.
Red blood cell extravasation is common and blood vessels surrounded by collagen with (fine) peripheral spokes (amianthoid fibers) are usually seen.

Immunostains for smooth muscle actin and cyclin D1 are characteristically positive.
The main histologic differential diagnosis is schwannoma.
IPMs are diagnosed by examination of the tissue by a pathologist.
They have a rim of peripheral lymphoid tissue (remnant of a lymph node) and consist of spindle cells with nuclear palisading. Red blood cell extravasation is common and blood vessels surrounded by collagen with (fine) peripheral spokes (amianthoid fibers) are usually seen.
Immunostains for smooth muscle actin and cyclin D1 are characteristically positive. The main histologic differential diagnosis is schwannoma.
Intranodal palisaded myofibroblastoma