1 Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43 Gil, Songpa-gu, Seoul 138-736, Republic of Korea.
2 Department of Pathology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
AJR Am J Roentgenol. 2018 Aug;211(2):W98-W108. doi: 10.2214/AJR.17.18807. Epub 2018 Jun 21.
The purpose of this study is to evaluate the MRI features of primary anorectal malignant melanoma and to correlate these features with its clinical and pathologic characteristics.
The medical records of 12 patients (five men and seven women; mean age [± SD], 60.8 ± 10.0 years) with pathologically proven primary anorectal melanoma were retrospectively reviewed. MRI findings were analyzed to determine the shape, size, distance from the anal verge, presence of perirectal or anal infiltration, signal intensity on T1- and T2-weighted images, presence of diffusion restriction, contrast enhancement pattern of the lesion, presence of lymphadenopathy, and occurrence of bowel obstruction. Subsequent follow-up data for the patients were recorded.
The most common presentation was hematochezia (41.7% of patients). Common findings on MRI included a large intraluminal polypoid mass (75.0% of lesions) with little perirectal or anal infiltration (100.0%), T1 hyperintensity (66.7%), high T2 signal intensity (54.5%) or mixed T2 signal intensity (45.5%), restricted diffusion (100.0%), and hyper-enhancement (100.0%). The mean length, width, and depth of these masses were 3.5, 2.9, and 2.3 cm, respectively. The mean distance from the anal verge was 1.8 cm. Lymphadenopathy was frequently identified (75.0% of cases), with lymph nodes larger than 2 cm noted in 28.5% of cases and most commonly involving the perirectal area (77.8% of cases). No colonic obstructions were observed. The mean patient follow-up was 32.7 months. A total of 25.0% of patients died as a result of disease progression.
The possibility of the presence of anorectal melanoma should be considered for patients with a bulky intraluminal polypoid mass in the anorectum without colonic obstruction, with the mass showing T1 hyperintensity, high or mixed signal T2 intensity, hyperenhancement, minimal perirectal or anal infiltration, and lymphadenopathy.
本研究旨在评估原发性肛门直肠恶性黑色素瘤的 MRI 特征，并将这些特征与其临床和病理特征相关联。
回顾性分析 12 例经病理证实的原发性肛门直肠恶性黑色素瘤患者的病历（男 5 例，女 7 例；平均年龄[±标准差]，60.8±10.0 岁）。分析 MRI 结果以确定病变的形状、大小、距肛门缘的距离、是否存在直肠周围或肛门浸润、T1 加权像和 T2 加权像上的信号强度、弥散受限的存在、病变的增强模式、是否存在淋巴结肿大以及是否发生肠梗阻。记录患者的后续随访数据。
最常见的表现是血便（41.7%的患者）。MRI 常见表现包括大的腔内息肉样肿块（75.0%的病变），直肠周围或肛门浸润少（100.0%），T1 高信号（66.7%），高 T2 信号强度（54.5%）或混合 T2 信号强度（45.5%），弥散受限（100.0%）和高增强（100.0%）。这些肿块的平均长度、宽度和深度分别为 3.5、2.9 和 2.3cm。距肛门缘的平均距离为 1.8cm。常发现淋巴结肿大（75.0%的病例），28.5%的病例淋巴结大于 2cm，最常见于直肠周围（77.8%的病例）。未观察到结肠梗阻。平均患者随访时间为 32.7 个月。共有 25.0%的患者因疾病进展而死亡。
对于无结肠梗阻、直肠腔内有大息肉样肿块、T1 高信号、高或混合 T2 信号强度、高增强、直肠周围或肛门浸润少、淋巴结肿大的患者，应考虑存在肛门直肠恶性黑色素瘤的可能性。
