Mediastinal glomangioma: CT and octreotide scintigraphy appearance, and review of the literature.

The glomus body is a neuromyovascular, arteriovenous structure primarily found in the skin and, less commonly, other organs, and is involved with thermoregulation. Neoplasms of the glomus organ are most commonly encountered in the skin and soft tissues of the extremities, particularly the subungual region. Glomus tumors are rare vascular neoplasms originating from the glomus body resulting from proliferation of modified muscle cells within this organ. Glomus tumors are commonly subdivided, based on the prominence of glomocytes, vascular structures, and smooth muscle cells, into solid glomus tumors (the most common variant), glomangioma, and glomangiomyoma. Previous reports of intrathoracic glomus tumors have shown that these tumors are most commonly encountered within the tracheobronchial tree or pulmonary parenchyma; mediastinal lesions are exceptionally rare. On the basis of imaging appearance of the glomangioma reported in this case as well as prior reports of tracheobronchial and pulmonary glomus tumors, mediastinal glomus tumors manifest as intensely enhancing masses with circumscribed or poorly defined margins, closely resembling thymic carcinoid tumor, pheochromocytoma, or hypervascular lymphadenopathy. Secretion of catecholamines and tracer uptake on Indium-111 octreotide scintigraphy, as seen in the present case, is probably exceptional. Because glomus tumors may be difficult to diagnose on routine histopathologic specimens, radiologists should be aware of this rare lesion and consider the diagnosis of glomus tumor when an intensely enhancing mediastinal mass is encountered.