Angiomatoid fibrous histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue cancer that affects children and young adults.

Pathology
It is characterized by cystic blood-filled spaces and composed of histiocyte-like cells. A lymphocytic cuff is common. It often simulates a vascular lesion, and was initially described as doing this.

AFH typically has a chromosomal translocation involving the ATF1 gene -- t(12;16) FUS/ATF1 or t(12;22) EWS/ATF1.