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

To analyze the ultrasound diagnosis and differential diagnosis of medium and small choroidal melanomas. 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. 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 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 (0.016, 0.199, both 0.05), while the low echo and large base-height ratio were risk factors of choroidal metastasis (0.011, 0.073, both 0.05). 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. .