The caruncular mass was initially thought to be a metastasis from her breast carcinoma. Magnetic resonance imaging showed an enhancing mass in the medial aspect of the right orbit inferior to the medial rectus, measuring 9 × 11 × 13 mm (Figure 1B). An incisional biopsy was performed, and histopathological analysis showed sheets of medium-sized malignant cells with minimal cytoplasm, pleomorphic nuclei, and numerous mitoses and apoptotic cells, initially thought to be consistent with metastatic ductal adenocarcinoma of the breast. However, immunohistochemical stains were negative for keratin, estrogen and progesterone receptors, and lymphoid and melanocytic markers. The tumor cells stained strongly for vimentin, smooth muscle actin, desmin, myogenin, and MyoD1 (Figure 2). Although the initial histological analysis suggested embryonal rhabdomyosarcoma, the final diagnosis of alveolar rhabdomyosarcoma was confirmed by fluorescence in situ hybridization analysis; this demonstrated a PAX3 -FKHR gene fusion, molecular evidence for the t(2;13) chromosomal translocation that is diagnostic for the alveolar subtype. The prognosis of orbital alveolar rhabdomyosarcoma is worse than that of the embryonal subtype. A complete workup including computed tomography, magnetic resonance imaging, bone scan, and bone marrow biopsy did not reveal any other lesions or metastases.