[Ultrasound diagnosis and differential diagnosis of medium and small choroidal melanomas]

Objective: To analyze the ultrasound diagnosis and differential diagnosis of medium and small choroidal melanomas. Methods: It was a retrospective case series study. Thirty-six cases (36 eyes) with medium or small choroidal melanoma were collected between January 2016 and January 2017 in Beijing Tongren Hospital, including 16 males and 20 females aged (50±12) years old. All tumors' apical heights were within 5 mm and the largest basal diameter was within 15 mm. Sixty-nine cases (69 eyes) with choroidal hemangioma, including 45 males and 24 females aged (45±11) years old, and 16 cases (19 eyes) with choroidal metastasis, including 4 males and 12 females aged (50±11) years old, of equal size were also analyzed as differential diagnosis. Univariate (Chi-square test, Fisher's exact test, and analysis of variance) and multivariate analyses (Logistic regression) were used for statistical analysis. Results: There were significant differences in morphology, height, base-height ratio, internal echo, choroidal excavation and secondary retinal detachment among the three types of tumors(all P<0.05). Approximately 91.7% (33/36) of choroidal melanomas and 94.2% (65/69) of hemangiomas were flat or dome, while 63.2% (12/19) of metastatic tumors showed a polygonal shape and an irregular surface contour. The average height was (4.02±0.70) mm for choroidal melanoma, (3.10±1.08) mm for metastasis and (2.75±0.87) mm for hemangioma. The base-height ratio of choroidal melanoma, metastasis, and hemangioma was 2.62±0.48, 4.09±1.18 and 3.16±0.58, respectively. About 86.1% (31/36) of choroidal melanomas and 84.2% (16/19) of metastases showed lower echo than adjacent orbital tissue, while 92.8% (64/69) of hemangiomas had similar or higher echo. About 16.7% (6/36) of choroidal melanomas showed choroidal excavation, but no such signs were found in other tumors. Approximately 80.6% (29/36) of choroidal melanomas, 78.9% (15/19) of metastases and 52.2% (36/69) of hemangiomas showed secondary retinal detachment. The internal echo, height and base-height ratio were taken as significant independent influencing factors into the Logistic regression model. The low internal echo and large height were risk factors of choroidal melanoma (OR=0.016, 0.199, both P<0.05), while the low echo and large base-height ratio were risk factors of choroidal metastasis (OR=0.011, 0.073, both P<0.05). Conclusion: Ultrasonography plays an important role in the diagnosis of medium and small choroidal melanomas, and the echo, height, and base-height ratio of the lesion can be helpful for the diagnosis and differential diagnosis. (Chin J Ophthalmol, 2018, 54: 843-848).