Gestational choriocarcinoma metastasis to the extraocular muscle: a case report.

This case report describes a biopsy-proven metastasis of gestational choriocarcinoma to the medial rectus muscle. Patient evaluation and follow up included comprehensive ophthalmologic history and examination, external and fundus photography, immunohistochemistry preparations of the medial rectus muscle specimen, MRI, ultrasound of the abdomen and pelvis, comprehensive blood tests, and CT scans of the chest, abdomen, and pelvis. The tissue specimen was obtained via a medial perilimbal conjunctival peritomy. MRI revealed a mass intrinsic to the right medial rectus muscle. Immunohistochemical staining confirmed gestational choriocarcinoma metastasis in medial rectus muscle biopsy. The patient showed general and orbital improvement following 7 subsequent cycles of chemotherapy. In conclusion, gestational choriocarcinoma may metastasize to the orbit in addition to the previously reported ocular site, the choroid. A chemotherapy regimen of etoposide, methotrexate, actinomycin-D, cyclophosphamide, and vincristine can effectively treat the intraorbital component of the disease.