Clinical Implications of Ultrasound-Based Morphology in Choroidal Melanoma

To describe the frequency of different B-scan morphologies and their association with clinical features and outcomes.

Cohort study of patients enrolled in the Prospective Ocular Tumor Study from January 2000 to January 2024 initially seen at Mayo Clinic Rochester.

Consecutive inclusion of patients with posterior uveal melanoma.

B-scan ultrasounds were performed by an experienced technician and treatment modalities were implemented by the attending oncologist.

Tumors were classified by shape as observed on B-scan. Enucleation-free survival, metastasis-free survival (MFS), and overall survival rates were analyzed using Cox-regression models and Kaplan-Meier curves.

Among 1021 cases of uveal melanoma, 739 (72.4%) were dome-shaped, 119 (11.7%) were mushroom-shaped, 85 (8.3%) were multilobulated, 77 (7.5%) were minimally elevated, and 1 (0.1%) was diffuse. The median follow-up duration after presentation was 37 months (interquartile range [IQR], 3-324). The macula was more commonly involved in minimally elevated tumors compared with the other groups (63.6% vs. 13.8%, P < 0.001). These tumors also exhibited a larger proportion of high internal reflectivity (13% vs. 2.3%, P < 0.001). The multilobulated group exhibited a significantly larger diameter at baseline (median, 15 mm; IQR, 6.1-30), whereas the mushroom-shaped group had greater thickness (median, 7.9 mm; IQR, 1.3-17.3) compared with the other groups (P < 0.001). Enucleation-free survival at 36 months was lower for mushroom-shaped (60.1%; 95% confidence interval [CI], 47.7-70.3) and multilobulated tumors (71.1%; 95% CI, 55.7-82.7). At 36 months, multilobulated tumors had lower MFS (68.2%; 95% CI, 55-78.2) and overall survival (73.9%; 95% CI, 59.9-83.64). On multivariate analysis adjusted for tumor thickness and diameter, multilobulated melanomas had a higher risk of metastasis (hazard ratio [HR], 2.08; P = 0.003) and death (HR, 2.38; P < 0.001).

Choroidal melanoma configuration by B-scan can vary from minimally elevated to dome-shaped to mushroom-shaped or multilobulated. Independent of presenting tumor size, multilobulated morphology was identified as a predictor for metastasis and death. Multilobulated melanomas, identified by a readily available tool such as ultrasonography, warrant a vigilant approach and close monitoring due to a potential association with poor prognosis.

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