On standardized A-scan ultrasonography, a dome-shaped choroidal tumor shows low internal reflectivity with regular internal structure and pronounced sound attenuation. The most likely diagnosis is:

• A Choroidal metastasis
• B Circumscribed choroidal hemangioma
• C Choroidal osteoma
• D Choroidal melanoma ✓

Explanation

Malignant choroidal melanoma characteristically shows low to medium internal reflectivity on standardized A-scan, reflecting its densely packed uniform cellularity, together with regular internal structure and marked attenuation of echoes behind the tumor. Choroidal hemangiomas and most metastases show high to medium-high internal reflectivity because of their vascular or loosely arranged stroma. Choroidal osteoma is strongly calcified and gives extremely high surface spikes with shadowing behind it.

Reference: Ryan's Retina, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.