This chapter includes tumors considered to be fibromas and benign fibrous histiocytomas. All of these tumors are fibroblastic-myofibroblastic growths. Most but perhaps not all of these are true neoplasms. Fibrocartilaginous pseudotumor is included because of its anatomic juxtaposition with nuchal fibroma. Nuchal fibroma and irritation fibroma of the oral cavity are other probably reactive processes. Fibromas typical of children are discussed in Chapter 9. Cellular angiofibroma is discussed with solitary fibrous tumor (Chapter 12).

ELASTOFIBROMA

Clinical Features

Originally described by Järvi et al. in 1961 as “elastofibroma dorsi,” this clinicopathologically distinctive fibrous proliferation is rich in thick, convoluted elastic fibers. Elastofibroma occurs in middle-aged and older adults almost exclusively underneath the lower end of scapula below the dorsal muscles in the posterior chest wall. Armed Forces Institute of Pathology (AFIP) cases show a mild male predominance, especially in the older age groups (Fig. 7.1). Autopsy and radiologic studies have suggested that incidental microscopic elastofibromas are quite common (10%–20%), and a large series from Okinawa has been published. Reactive origin, possibly by chronic minor trauma, was originally suggested, although recent findings showing clonal chromosomal changes suggest a neoplastic nature. Behavior is benign, and recurrences do not develop.

Lesions containing abundant elastic fibers and designated as elastofibromas have been reported in other locations, such as the plantar foot and in the gastric wall; the latter patient also had elastofibroma in the back. The author has also seen colonic polyps rich in elastic fibers.