Angiomatoid fibrous histiocytoma of the pulmonary artery: a multidisciplinary discussion.

Aims: Angiomatoid fibrous histiocytoma (AFH) is a rare neoplastic disease usually occurring in the dermis or subcutis of the extremities of young adults or children. Although sporadic cases in deep soft tissue and visceral organs have been reported, we present here the first description of AFH developing in a large artery.

Methods And Results: Paraffin sections of the surgical specimen were stained with haematoxylin and eosin, and immunohistochemistry was performed (CKAE1/AE3, EMA, CD34, p63, CD38, smooth muscle actin, and desmin). In addition, FISH and RT-PCR were applied in order to check for EWRS rearrangement. The histomorphological features, and FISH analysis revealing rearrangement of EWSR, indicated the definitive diagnosis of AFH. RT-PCR confirmed EWSR rearrangement, and detected an EWSR1-ATF1 fusion transcript.

Conclusions: A thoracic location of AFH has not been reported until very recently, and shares a differential diagnosis with diverse neoplasms, including spindle cell carcinoma and low-grade sarcoma. We describe the first reported case of thoracic AFH arising in a large vessel, and highlight distinctive histological and molecular features.