Nodular fasciitis is a benign nodular proliferation of connective tissue that usually involves superficial fascia (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20). Konwaler and associates (2) originally called it “subcutaneous pseudosarcomatous fibromatosis.” It is now recognized to be a fairly common condition (1). Its occurrence in the orbital area was elucidated by Font and Zimmerman in 1966 (3) and subsequent reports have expanded on its ophthalmic manifestations (4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20). In the authors’ series of 1,264 orbital lesions, there were 2 cases, accounting for 15% of all fibrocytic lesions and for 1% of all orbital masses. It may be more common than indicated in that report because some cases are probably misdiagnosed histopathologically as other spindle cell lesions.

Nodular fasciitis usually occurs in children and has a rather rapid onset and progression. It tends to occur in anterior periocular structures where it is visible or palpable and has rarely been observed in the deep orbit. It can simulate a dermoid cyst clinically (7).

The diagnosis of nodular fasciitis can be suspected on the basis of clinical findings, but is usually made histopathologically after biopsy or surgical excision. With imaging studies, it shows features typical of other solid masses and has no distinctive findings.

The histopathologic diagnosis of nodular fasciitis can be challenging, because it can simulate rhabdomyosarcoma or other soft tissue sarcomas (1,2,3). However, pathologists experienced with soft tissue tumors usually can make the diagnosis based on characteristic light microscopic features. Mitotically active stellate or spindle-shaped fibroblasts are often arranged in parallel bundles and extend in all directions, resembling cells in a tissue culture. Numerous newly formed parallel capillaries often ramify through the lesion, forming slitlike spaces reminiscent of those seen in Kaposi sarcoma. With immunohistochemistry, nodular fasciitis shows positive reactions against smooth muscle actin and vimentin. With electron microscopy, one sees parallel bundles of actinlike filaments with fusiform densities (17).

Because nodular fasciitis usually is well circumscribed and located in the anterior adnexal structures, we recommend complete surgical removal when possible. Local recurrence is rare after complete excision.

Among the benign fibrous proliferations, fibroma is a difficult lesion to categorize (1). It is possible that reported cases of orbital fibroma would be reclassified today as solitary fibrous tumor (SFT), fibrous histiocytoma, or other spindle cell lesions (1,2). Nevertheless, we have retained it in this edition because of prior publications (4,5,6,7). It appears to be a benign neoplasm or reactive process that may arise from Tenon’s fascia or its precursors. It has been reported in the orbital region (3,4,5,6,7,8).

Fibroma in the orbital area usually appears as a palpable firm mass in the anterior orbit that produces proptosis or globe displacement. It can extend anteriorly into the conjunctiva and appear as an irregular, yellow-white mass.

There is little specific information on the diagnosis of orbital fibroma. Clinically and with imaging studies, it probably appears as a solid, anterior, yellow-white mass with irregular borders.

Fibroma is composed of a paucicellular population of fibroblasts that are sometimes widely separated by abundant collagen. The long, graceful fascicles typical of fibroma and other pure fibroblastic tumors appear different on light microscopy from the twisting storiform pattern of the cells of fibrous histiocytoma. The absence of foci of inflammation is helpful in differentiating fibroma from sclerosing idiopathic orbital inflammation, in which inflammatory cells can usually be detected despite large areas of fibrosis.

The diagnosis of orbital fibroma is not usually made clinically; as with most primary circumscribed orbital soft tissue tumors, the best management is complete surgical removal. Incomplete surgical removal can lead to recurrence. The approach to surgery is determined by the size and location of the tumor on orbital computed tomography (CT). Orbital fibromas are probably not radiosensitive, although it seems reasonable to attempt radiotherapy in recurrent or unresectable cases that show progression and complications.