Qiu Yongkang, Jiao Hao, Huang Wenpeng, Chen Zhao, Yang Qi, Wu Sitong, Sun Xinyao, Kang Lei
Department of Nuclear Medicine, Peking University First Hospital Beijing 100034, China.
Am J Nucl Med Mol Imaging. 2022 Dec 15;12(6):188-194. eCollection 2022.
Malignant melanoma (MM) is an aggressive malignant tumor, which mostly occurs on the skin, uvea, etc. The mucosal MM accounts for a small proportion of all MM and can occur in the digestive tract. Primary MM of the digestive tract is rare and can be found in the middle and lower third of the esophagus and the rectum containing melanocytes. Primary rectal MM often occurs in middle-aged and elderly women, with rapid progress and strong invasion. We report a case of a 61-year-old man diagnosed with primary malignant melanoma of the rectum with liver metastases mimicking rectum cancer. F-FDG PET/CT showed the rectal wall was markedly thickened with a high metabolic level (SUVmax 10.6) and the boundary between the lesions and the prostate was unclear. In addition, increased FDG uptake were found in multiple lymph nodes, lung, liver, and bones, suggesting metastasis. In this case, F-FDG PET/CT shows the advantage of evaluating the whole-body situation and provides valuable information for the diagnosis, tumor stage, evaluation of treatment efficacy, and prognosis of MM.
恶性黑色素瘤（MM）是一种侵袭性恶性肿瘤，主要发生于皮肤、葡萄膜等部位。黏膜MM在所有MM中占比小，可发生于消化道。消化道原发性MM罕见，可在含有黑素细胞的食管中下段及直肠发现。原发性直肠MM常发生于中老年女性，进展迅速，侵袭性强。我们报告一例61岁男性，诊断为原发性直肠恶性黑色素瘤伴肝转移，临床表现酷似直肠癌。F-FDG PET/CT显示直肠壁明显增厚，代谢水平高（SUVmax 10.6），病变与前列腺之间界限不清。此外，在多个淋巴结、肺、肝和骨骼中发现FDG摄取增加，提示转移。在该病例中，F-FDG PET/CT显示了评估全身情况的优势，为MM的诊断、肿瘤分期、治疗疗效评估及预后提供了有价值的信息。
