Answer: Spindle cell hemangioendothelioma

Histology: At low power, the submucosa is filled with a proliferation of gaping thin-walled vessels reminiscent of a cavernous hemangioma. Admixed with these open blood vessels are intervening solid areas. At higher power, these solid areas represent collapsed vascular spaces and a proliferation of spindled cells and occasional rounded cells. The cells are relatively bland without appreciable pleomorphism or mitotic activity.

Discussion: Spindle cell hemanioendothelioma (SCH) is an uncommon vascular tumor that usually arises in the distal extremities. Origin from the mucosa of upper respiratory tract is exceedingly rare, but has been reported. These lesions are usually multifocal, and they sometimes arise in patients with Maffucci’s syndrome.

As is demonstrated in the present case, SCH is histologically characterized by the admixture of cavernous hemangioma-like areas and solid areas resembling Kaposi’s sarcoma. If each component is interpreted individually, SCH could be confused with a cavernous hemangioma or Kaposi’s sarcoma respectively. It is an appreciation for its dual components that permits recognition as SCH. In further contrast to Kaposi’s sarcoma, the majority of SCHs are partially or completely intravascular (a finding not apparent in the present case). The absence of cellular atypia should permit distinction from an angiosarcoma.

SCH does not metastasize, although about 60% locally recur. In reality, local recurrences may represent contiguous spread or multifocal involvement of a vessel. Many have questioned whether SCH actually represent a true neoplasm. Instead, SCH may represent a vascular malformation.