FCCT Blog Post #22
By Randy Hurley MD, cTropMed
HealthPartners and Regions Hospital Cancer Care Centers
Global Health Faculty, University of Minnesota
KCMC-FCCT Tumor Board
July 22, 2026
A case of a 50-year-old woman with a right eye tumor was presented at the July Tumor Board. She had presented in February 2026 with a several month history of right eye symptoms and proptosis. A CT of the head identified a 3.6cm right coronal tumor involving the right lateral rectus muscle. She underwent an excisional biopsy. The pathology identified a highly vascular spindle cell tumor with occasional large pleomorphic cells that morphologically suggested a sarcoma. A limited immunohistochemistry (IHC) panel was available: the tumor was S100 negative; CD34 staining (which can stain normal vascular endothelium, angiosarcomas and myeloid neoplasms) was positive in the vascular endothelium of the tumor, but the large neoplastic cells and background spindle-shaped cells were negative. A post-operative CT scan revealed residual tumor in the right lateral orbit. A CT of the chest and abdomen did not identify metastatic disease. A differential diagnosis included angiosarcoma of the eye, an atypical lymphoma, a uveal melanoma or rhabdomyosarcoma. The spindle-cell morphology would be consistent with sarcoma however the lack of tumor-cell staining with CD34 would be inconsistent with an angiosarcoma. The morphology was not consistent with lymphoma and the patient was HIV negative. There was not a retinal/uveal component to the tumor making uveal melanoma less likely. Additionally, rhabdomyosarcoma is typically a pediatric tumor. Although it can be cost prohibitive, an extended panel of IHC was recommended to better define the pathology. A consideration was also given to begin with several simple IHC stains to exclude lymphoma (CD45 and/or CD20). An orbital lymphoma would be treated with systemic chemotherapy and radiation with curative intent whereas the other entities in the differential diagnosis likely would require enucleation.
Randy Hurley MD, cTropMed
Global Health Faculty, University of Minnesota
