Occult lobular breast cancer presenting as an orbital metastasis

What happened, in summary

A 66-year-old woman developed swelling of the left lower eyelid and a slowly growing orbital mass over 2 months. She had some ocular discomfort but no pain, double vision or visual loss. Examination found a palpable mass in the lower left orbit with minor upward displacement of the eye.

Orbital CT initially suggested lymphoma. Biopsy instead showed metastatic carcinoma, and repeat tissue testing was positive for estrogen and progesterone receptors, CK7 and CK CAM5.2 and negative for HER2 and E-cadherin. Mammography, breast ultrasound and breast MRI did not reveal a primary breast mass.

Systemic imaging identified multiple bone lesions, including the left femur, iliac bone, sacrum and cervical and lumbar spine, as well as a right axillary lymph node. Excision of the axillary node showed the same pattern, consistent with metastatic lobular breast carcinoma. The findings confirmed Stage IV disease.

She started chemotherapy and hormonal therapy. The orbital metastasis decreased with treatment, and systemic disease remained controlled under hormonal therapy. Clinical follow-up continued for 5 years, with imaging every 6 months.