Most Common Cancers Causing Choroidal Metastases
Breast cancer (40-47%) and lung cancer (21-29%) are the two most common primary malignancies that metastasize to the choroid, with breast cancer being the leading cause overall. 1
Primary Cancer Distribution
The choroid is the most common site for intraocular metastatic disease due to its rich vascular supply. The hierarchy of primary cancers causing choroidal metastases is well-established:
- Breast cancer: 40-47% of all choroidal metastases 1, with a notable finding that 53% of patients in one series had breast cancer as the primary 2
- Lung cancer: 21-29% of cases 1, representing 26-53% in various series 2, 3
- Other primaries (much less common): kidney, gastrointestinal tract, melanoma, thyroid, prostate, cervical, and ovarian cancers 2
Key Clinical Patterns to Recognize
Gender-Specific Considerations
- Women: Breast carcinoma is the most common primary
- Men: Lung cancer is the most common primary 4
Laterality and Multiplicity Patterns
These patterns help identify the likely primary source:
- Bilateral, multifocal metastases: Most often secondary to breast cancer 1, 3
- Unilateral, unifocal metastasis: More commonly associated with lung cancer 5, 1
Temporal Presentation
The timing of choroidal metastasis differs significantly by primary tumor:
- Lung cancer: Mean interval of 9 months after primary diagnosis; choroidal metastasis is the first clinical sign of tumor disease in 58% of patients 2
- Breast cancer: Mean interval of 68 months (over 5 years) after primary diagnosis; choroidal metastasis is the first sign of metastatic disease in 28% of patients 2
Critical Clinical Pitfall
In 18% of patients presenting with choroidal metastasis, there is no prior history of cancer 2. In these cases, lung cancer is the most likely culprit—12 of 13 patients without known cancer history were diagnosed with lung cancer upon workup. This underscores the importance of comprehensive systemic evaluation when choroidal metastasis is identified, even without known malignancy.
Lung Cancer Subtype Specificity
While adenocarcinoma is the primary lung cancer subtype associated with choroidal metastasis, small cell lung cancer (SCLC) rarely involves the choroid 5. When SCLC does metastasize to the choroid, it typically presents as unilateral lesions.
Systemic Disease Implications
Choroidal metastasis indicates widespread systemic disease in 96% of patients 2. This finding serves as a red flag for extensive metastatic burden and necessitates comprehensive staging, including chest CT, abdominal CT, and bone scintigraphy to identify additional metastatic sites.