Orbital solitary fibrous tumor: A rare clinicopathologic correlation and review of literature
A 31-year-old man presented at a tertiary care eye hospital in India with complaints of painless but slowly progressive protrusion of the right eyeball with fullness above the lids since the past 6 months. The best corrected visual acuity was 20/20, N6. Hertels at a base of 104 mm showed a proptosis of 4 mm. Ocular movements revealed restricted upgaze in the right eye. Palpation of the superior orbit revealed a well-defined mass that was non-tender, compressible and non-pulsatile in nature. Computed tomography CT scan showed a heterogenous but well defined mass in the right superior orbit with a moderate but progressively increasing contrast enhancement [Figure and ]. The globe, bony orbit and other orbital soft tissues were found to be within normal limits.\nA provisional diagnosis of a well-defined, moderate flow vascular lesion was made and a plan to surgically excise the lesion was made. A Benedict's incision was used to approach the superior orbit. The lesion was found to have a capsule around it but was not adherent to the surrounding orbital soft-tissues and thus a cryotherapy assisted complete excision was carried out without much difficulty. The post-operative period was uneventful. Hertel's exophthalmometry confirmed absence of a proptosis and the surgical wound healed well. Last examination was 1-year post-operatively without any evidence of recurrence and the patient is on a follow-up.\nGross examination showed a pinkish mass whose cut section was pinkish-grey with multiple areas of hemorrhage. Microscopic examination showed an encapsulated tumor with cellular and cystic areas. Spindle shaped tumor cells arranged in whorls with minimal atypia, moderate nuclear pleomorphism and inconspicuous nucleoli were noted []. The tumor showed vessels of varying caliber, dilated to compressed, lined by flattened endothelium []. However, stag horn channels and giant cells were not noted. Immunohistochemistry showed tumor cells showing a positive staining with CD99 [], strongly positive for CD34 and BCL-2 [] and background positivity for vimentin []. However, reticulin staining [] and smooth muscle actin (SMA) were negative []. The morphological and immunohistochemical features were consistent with a diagnosis of orbital SFT.