Answer: The fundoscopic exam of the right eye reveals a cream colored well-circumscribed intraocular mass with smaller adjacent mass inferiorly. Therefore, the best next step is to obtain imaging, more specifically MRI of the brain and orbits.
Though genetic testing could be helpful for confirming the diagnosis, it would not be the next best step. Similarly, bone scan and lumbar puncture would be helpful if suspecting metastasis but imaging would still take precedence.
Fine needle aspiration biopsy of any intraocular mass concerning for malignancy is not recommended due to increased risk of seeding. Serology would be useful for detecting toxocariasis. However, toxocariasis would not present with the above dilated fundoscopy findings.
You order an MRI brain and orbits. An image is shown below: