Sagittal T1-weighted magnetic resonance image showing a fusiform mass surrounding the optic nerve in the posterior orbit.
Histopathology of the biopsy specimen (original magnification ×128). A, Spindle and oval tumor cells with scant cytoplasm, few mitoses, and moderate pleomorphism (hematoxylin-eosin). B, Smooth muscle actin stain showing diffuse, positive staining. C, In situ hybridization study showing diffuse staining for Epstein-Barr virus by tumor cells.
Kim JW, Lee DK, Fishman M. Orbital Smooth Muscle Tumor Associated With Epstein-Barr Virus in a Human Immunodeficiency Virus–Positive Patient. Arch Ophthalmol. 2010;128(8):1084-1085. doi:10.1001/archophthalmol.2010.146
Immunodeficiency has been recognized as a risk factor for the development of orbital and adnexal tumors such as Kaposi sarcoma and non-Hodgkin lymphoma. Smooth muscle tumor (SMT) associated with Epstein-Barr virus (EBV) (SMT-EBV) is a rare entity that may be encountered in human immunodeficiency virus (HIV)–infected patients and organ transplant recipients. We describe an HIV-positive man who was diagnosed with an orbital SMT-EBV after presenting with a progressive retrobulbar mass.
A 43-year-old HIV-positive man (CD4 lymphocyte count, 175/mL) was referred to the orbit service with progressive left proptosis and vision loss. On magnetic resonance imaging, there was a fusiform orbital mass surrounding the posterior portion of the optic nerve (Figure 1); the diameter of the mass had enlarged from 14 mm to 25 mm over a 9-month period on serial scans. The patient had visual acuity of no light perception, 2 mm of proptosis, and left optic disc edema. During orbital biopsy, the deep intraconal mass was noted to be a firm, whitish tumor. Permanent sections revealed the mass to be a proliferation of bland spindle cells with low mitotic activity (Figure 2A) and a Ki-67 labeling index of 18%. Immunohistochemistry results were negative for S-100 protein, desmin, epithelial membrane antigen, and CD34, but stains were positive for smooth muscle actin (Figure 2B). In situ hybridization study results were strongly positive for EBV (Figure 2C). The final pathologic diagnosis was SMT-EBV.
To our knowledge, this is the first case of a primary orbital SMT-EBV reported in the literature. Our patient had documented HIV but no previously identified SMTs elsewhere in the body. Although a rare entity, cases of SMT-EBV have been reported in HIV-positive patients, organ transplant recipients, and other immune-compromised individuals.1- 4 Typically SMT-EBV is a multifocal disease, with tumors arising in the abdominal cavity, adrenal glands, liver, and epidura of the brain and spinal cord.1- 4 A case series of 19 patients with SMT-EBV reported by Suankratay et al1 listed 1 patient with an orbital mass, although details were limited and the patient also had tumors in the spinal cord, vocal cord, and adrenal glands. There is no reliable treatment currently available for SMT-EBV; chemotherapy and radiotherapy are thought to be ineffective, and recurrences following surgical excision are common.2 A fusiform orbital mass in an HIV-positive patient that demonstrates progressive enlargement may be due to a rare entity: SMT-EBV.
Correspondence: Dr Kim, Department of Ophthalmology, Stanford Medical Center, 900 Blake Wilbur Dr, W3001, Stanford, CA 94304 (firstname.lastname@example.org).
Financial Disclosure: None reported.