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Figure 3: Histology of orbital core biopsy showing infiltration by metastatic
adenocarcinoma, most likely of breast origin
part of the choroid. It has been proposed that breast
[7]
cancer cells have the ability to remain viable away from
their primary site. Indeed, breast cancer accounts for the
highest incidence of metastasis to the orbit, [2,3,5-9] followed
Figure 1: Axial T1 MRI of skull showing an abnormal infiltrating lesion at the
right orbital apex involving all four rectus muscles by prostatic, lung, melanoma, and gastrointestinal cancers.
Another study showed that lung cancer was the second most
common primary source for orbital metastasis, followed
by prostate cancer. Other reported sources include cancers
of the thyroid, liver, pancreas, adrenal gland, salivary and
choroidal melanoma. [6]

Overall, orbital metastasis occurs in 2-3% of patients with
systemic cancer. However, metastasis into the extraocular
[6]
muscles is an even less frequent presentation. It did,
[1]
however, occur in this reported case of breast carcinoma
metastatic to the orbit, with all four recti muscles being
involved. This is not in concordance with the prevailing
view that skeletal muscles are considered an uncommon
site for metastasis, (albeit less infrequent in malignant
lymphoma and leukemia). It may be due to the fact that these
muscles are in a more or less constant state of movement,
thus preventing neoplastic cells from seeding them, or
by producing an unfavorable chemical environment for
neoplastic growth. Clinical studies have shown that
[5]
different cancer types frequently display distinct metastatic
Figure 2: Coronal T1 MRI of skull shows intra- and extra-conal soft tissue patterns, with neoplasms of particular histological types
signal intensity lesion encroaching upon right optic nerve, likely infiltrating tending to metastasize to specific organs. Paget
[10]
[11]
and effacing retrobulbar fat
first proposed the “seed and soil” hypothesis of cancer
positive, progesterone receptor positive and HER2 negative metastasis. He postulated that tumor development was
(Luminal A). Staging investigation unfortunately revealed a consequence of the provision of a fertile environment
diffuse bony metastases. The consensus of our team was to (the soil) in which compatible tumor cells (the seed) could
treat her with primary hormonal therapy and the patient was proliferate The ability or inability of specific organs to
treated with an aromatase inhibitor (Arimidex®) 1 mg once provide this favorable milieu and the success or failure
a day. Adjuvant radiotherapy to the right eye was also done of specific cells to respond to these microenvironments
under the direction of the ocular oncologist. dictated the observed patterns of metastatic development in
different cancers. In contrast to the “seed and soil” theory,
[11]
DISCUSSION there is a mechanistic explanation for secondary tumor
growth patterns. Here, the organ or tissue specificity is the
Orbital metastasis of solid tumors is very rare [2-6] with most direct consequence of the anatomical location of primary
occurring in the uveal tract, especially in the posterior tumors. Thus, the secondary foci of epithelial cancers,

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Journal of Cancer Metastasis and Treatment ¦ Volume 2 ¦ March 28, 2016 ¦