[Enophthalmos caused by orbital metastasis of breast carcinoma]

Orbital metastatic disease usually leads to exophthalmos but rarely to enophthalmos. We report a case of a metastasis causing enophthalmos.

A 68-year-old woman had mastectomy for breast cancer six years prior to presentation. She complained of double vision when looking sideways. The right eye showed a motility reduction in all directions and a slight ptosis. She had 4 mm enophthalmos, and the eyelids were sunk into the orbit. There were no signs of optic nerve damage. Magnetic resonance imaging showed a retrobulbar mass surrounding the optic nerve and infiltrating the muscles. The space of the orbital fat was reduced. A biopsy confirmed the diagnosis of metastatic breast carcinoma. Histologically, the connective tissue was infiltrated by lymphocytes, and the nuclei of the tumor cells where aligned in a linear "indian file" pattern. 30% of the tumor cells contained the estrogen-receptor protein, 40% the progesterone-receptor protein. The CA-15/3 and CEA levels were elevated. The patient underwent orbital radiation with 50 Gy. During the following 2 months, the enophthalmos increased to 6 mm.

We suggest the following hypothesis as the cause of enophthalmos in orbital metastases: The tumor growth goes along with fibrosis. Subsequent shrinkage of the connective tissue pulls the eye back into the orbit. The ensuing elevation of tissue pressure leads to atrophy of the retrobulbar fat. The increase of tumor volume is too slow to compensate for the fat atrophy. Slowly progressive enophthalmos with reduced motility is nearly pathognomonic of metastatic scirrhous breast carcinoma. In rare cases, a diffusely infiltrating carcinoma of the gastrointestinal tract may cause a similar picture.