What happened, in summary

A 61-year-old woman developed worsening double vision over 3 months and was initially treated elsewhere with steroids for presumed orbital inflammation. Her history was important: in March 2006, she had undergone modified radical mastectomy with axillary lymph-node clearing for right breast lobular carcinoma, staged T4N2M0 and grade 3. She then received 54 Gy of radiotherapy and chemotherapy. After that treatment, PET imaging showed complete clearance of the tumor, and estrogen and progesterone receptor testing at the time was negative. When she presented with eye symptoms in March 2008, examination showed restricted eye movements in both eyes, worse on the right. MRI showed thickening of the right superior, lateral, and inferior rectus muscles and the left superior rectus muscle. PET showed bulky, metabolically active extraocular muscles, along with active nodules in the right upper lung lobe and left lower lung lobe. Biopsy of the right superior rectus muscle confirmed metastasis from lobular breast carcinoma. Unlike the original tumor, the metastatic tissue was strongly estrogen receptor-positive and progesterone receptor-positive. Abdominal ultrasound and bone scan were normal. She received radiotherapy to the orbit and chest wall, along with tamoxifen for 6 months. Her double vision improved markedly after treatment, and eye movement recovered. At 18 months after presentation, PET showed no abnormality. Diplopia had resolved, though mild bilateral ptosis remained. This clinical course also shows receptor change between the original breast tumor and metastatic tissue: the first tumor tested hormone receptor-negative, while the ocular metastasis was strongly hormone receptor-positive, making tamoxifen a relevant treatment choice.