Markedly dilated vascular structure characterized by the loss of normal, organized arterial wall architecture. The native vascular wall is markedly thickened and largely composed of dense, hyalinized fibrous connective tissue, lacking a distinct and intact smooth muscle layer (tunica media) or elastic laminae. The markedly ectatic lumen is predominantly occupied by a massive, organizing mural thrombus. This intraluminal clot consists of thick, laminated layers of fibrin and aggregated erythrocytes (lines of Zahn), interspersed with zones of early peripheral organization featuring fibroblastic proliferation, capillary ingrowth, and scattered inflammatory cells. No evidence of atypia or malignancy.
Pulsatile swelling in the lateral aspect of the right wrist.
One soft tissue fragment measured 1.8x1.2x1 cm, totally embedded.
Rt. Wrist swelling, excision biopsy: