恶性黑色素瘤是一种由皮肤引起的高度侵袭性癌症,视网膜,和呼吸道的粘膜衬里,胃肠(GI),或泌尿生殖道,所有这些都含有黑素细胞。粘膜或皮肤外黑素瘤(ECM)很少见,占所有黑素瘤的1%。我们在此报告一例转移性粘膜黑色素瘤,表现为隐匿性失血性贫血。一名58岁的男性表现为全身无力,厌食症,减肥,间歇性黑便一年.在考试中,他是心动过速,临界低血压,苍白,没有上腹部压痛。实验室显示严重贫血[血红蛋白,Hgb3.8mg/dL,平均红细胞体积(MCV)72fl],他接受了两个单位的红细胞。内窥镜检查显示8毫米无出血,胃溃疡,胃壁边缘凸起,底部干净。组织学分析与对S-100、MelanA、和HMB45染色。腹部CT显示皮下多灶性转移性疾病,肌肉内,和怀疑小肠癌病的肾周植入物。患者接受了腹壁肿块的切除活检,手术病理证实为黑色素瘤。患者计划开始接受晚期疾病的免疫治疗。在胃肠道中发现的大多数黑色素瘤是转移性的。表现为胃溃疡的粘膜黑色素瘤极为罕见。因此,在诊断原发性胃黑色素瘤(PGM)之前,必须排除其他部位的转移。在我们的案例中,一种未知原发的广泛疾病阐明了诊断,但术后检查未能发现皮肤上的任何潜在病变,生殖器,或其他器官,提示可能诊断为转移性胃黑色素瘤。然而,仍需随访以根据既定标准确认诊断.黑色素瘤的病理诊断需要鉴定细胞质中的黑色素,并使用S-100,MelanA,HMB-45尽管PGM的病理诊断与皮肤黑色素瘤相似,由于发病率极低,术前诊断困难,缺乏明显的黑色素沉着,与更常见的胃癌类似的微观模式,医生和病理学家缺乏意识。粘膜黑色素瘤的预后较差,皮肤黑色素瘤的五年生存率为25%,而皮肤黑色素瘤的生存率为80%。高龄,手术无法切除的疾病,和淋巴结受累都是预后不良的标志物。没有标准的治疗方案。手术是可切除疾病的唯一治愈方法。辅助化疗,辐射,和免疫疗法在皮肤黑色素瘤中具有确定的作用,但关于粘膜黑色素瘤的辅助全身治疗的数据有限。必须进一步研究以建立针对这种罕见疾病实体的适当管理指南。
Malignant melanoma is a highly aggressive cancer arising from the skin, retina, and mucosal lining of the respiratory, gastrointestinal (GI), or genitourinary tracts, all of which contain melanocytes. Mucosal or extracutaneous melanomas (ECMs) are rare accounting for 1% of all melanomas. We herein report a case of a metastatic mucosal melanoma presenting as occult blood loss anemia. A 58-year-old male presented with generalized weakness, anorexia, weight loss, and intermittent melena for one year. On exam, he was tachycardic, borderline hypotensive, and pale without epigastric tenderness. Labs showed severe anemia [hemoglobin, Hgb 3.8 mg/dL, mean corpuscular volume (MCV) 72 fl] for which he received two units of red cells. Endoscopy revealed an 8 mm non-bleeding, gastric ulcer with a raised border and a clean base on the wall of the gastric body. Histologic analysis was consistent with malignant melanoma displaying strong positivity for S-100, Melan A, and HMB 45 stains. The CT of the abdomen revealed multifocal metastatic disease with subcutaneous, intramuscular, and perinephric implants with suspicion of small bowel carcinomatosis. The patient underwent an excisional biopsy for the abdominal wall mass and surgical pathology confirmed melanoma. The patient is planned to be started on immunotherapy for advanced disease. Most melanomas found in the GI tract are metastatic. Mucosal melanoma presenting as a gastric ulcer is extremely rare. As a result, metastasis from other sites must be ruled out before making a diagnosis of primary gastric melanoma (PGM). In our case, a widespread disease with unknown primary elucidated the diagnosis but post-operative inspection failed to find any potential lesion on the skin, genitals, or other organs, suggesting the possible diagnosis of metastatic gastric melanoma. However, follow-up is still required to confirm the diagnosis according to the established criteria. Pathologic diagnosis of melanoma requires the identification of melanin in the cytoplasm and immunohistochemistry with specific markers such as S-100, Melan A, and HMB-45. Although the pathologic diagnosis of PGM is similar to cutaneous melanoma, preoperative diagnosis is difficult due to the extremely low incidence, lack of obvious melanin pigmentation, similar microscopic patterns as more common gastric cancers, and lack of awareness among physicians and pathologists. The prognosis of mucosal melanoma is poor, with a five-year survival rate of 25% versus 80% for cutaneous melanoma. Advanced age, surgically unresectable disease, and lymph node involvement are all poor prognostic markers. There is no standard protocol for treatment. Surgery is the only curative treatment for the resectable disease. Adjuvant chemotherapy, radiation, and immunotherapy have an established role in cutaneous melanoma but there is only limited data on adjuvant systemic therapy with mucosal melanoma. Further research is imperative to establish proper management guidelines for this rare disease entity.