Details
65 year old male with a large, lobular, heterogeneous appearing mass around right lower lobe of the lung. It is unclear where the mass is arising.
Solitary fibrous tumour is a soft tissue neoplasm that frequently arises in the pleura but can occur at other sites. Grossly, the cut surface often appears solid with dense fibrous tissue. Microscopically, the tumour is typically comprised of spindle cells and collagenous stroma with irregularly distributed blood vessels (described as “staghorn”-like). The tumour cells are usually positive for CD34 and STAT6 by immunohistochemistry. Molecular studies have shown that these tumours often carry a NAB2-STAT6 fusion.
Clinically, solitary fibrous tumours only rarely metastasize. Features associated with increased incidence of recurrence and metastasis include: brisk mitotic activity including atypical mitotic figures, significant pleomorphism and atypia, high cellularity, and tumour cell necrosis.