Smith A E, Levi A W, Nadasdy T, Campbell K A, Fishman E K, Hruban R H
Department of Pathology, Weinberg 2242, The Johns Hopkins Medical Institutions, 401 N. Broadway, Baltimore, MD 21231, USA.
Cancer. 2001 Oct 1;92(7):1984-91. doi: 10.1002/1097-0142(20011001)92:7<1984::aid-cncr1718>3.0.co;2-0.
Pigmented neoplasms are extremely rare in the pancreas, and, when black pigment is identified, it often suggests the diagnosis of metastatic melanoma. The authors describe two patients with pigmented "black" neuroendocrine tumors of the pancreas. One patient had an incidental (0.5 cm) finding, and the second patient had a well-demarcated, 4.5-cm mass identified by computerized tomography that was consistent with an islet cell tumor.
The two neoplasms were resected surgically and studied by light microscopy using hematoxylin and eosin (H&E), Fontana-Masson, and iron stains. The neoplasms were examined immunohistochemically, and ultrastructural analysis was performed.
H&E stains revealed nests of well-differentiated cells with small, round, centrally placed nuclei. The cytoplasm of the neoplastic cells was pink and granular and contained abundant brown-black pigment. Angiolymphatic and perineural invasion were identified in the larger neoplasm. Both neoplasms demonstrated a positive reaction with a Fontana-Masson stain, which was susceptible to bleaching, and a negative reaction to an iron stain. Immunohistochemical stains showed that neoplastic cells expressed chromogranin and synaptophysin but did not express HMB-45, S-100 protein, glucagon, or insulin. Ultrastructural examination revealed regular neurosecretory granules (100-150 nm) and large, irregularly shaped, electron-dense granules with small lipid inclusions consistent with lipofuscin.
These pigmented pancreatic neoplasms are similar histologically and radiographically to the "black adenoma" of the adrenal gland. It is important to recognize these tumors, because they may mimic metastatic melanoma.
色素性肿瘤在胰腺中极为罕见，当发现黑色色素时，通常提示转移性黑色素瘤的诊断。作者描述了两名患有胰腺色素性“黑色”神经内分泌肿瘤的患者。一名患者为偶然发现（0.5 cm），另一名患者经计算机断层扫描发现一个边界清晰的4.5 cm肿块，与胰岛细胞瘤相符。
对这两个肿瘤进行手术切除，并采用苏木精-伊红（H&E）染色、Fontana-Masson染色和铁染色进行光镜检查。对肿瘤进行免疫组织化学检查，并进行超微结构分析。
H&E染色显示巢状分化良好的细胞，细胞核小、圆形，位于中央。肿瘤细胞的细胞质呈粉红色且颗粒状，含有丰富的棕黑色色素。在较大的肿瘤中发现了血管淋巴管和神经周围浸润。两个肿瘤的Fontana-Masson染色均呈阳性反应（该反应易被漂白），铁染色呈阴性反应。免疫组织化学染色显示肿瘤细胞表达嗜铬粒蛋白和突触素，但不表达HMB-45、S-100蛋白、胰高血糖素或胰岛素。超微结构检查显示有规则的神经分泌颗粒（100 - 150 nm）以及大的、形状不规则的、电子密度高的颗粒，伴有与脂褐素一致的小脂质包涵体。
这些色素性胰腺肿瘤在组织学和影像学上与肾上腺“黑色腺瘤”相似。认识这些肿瘤很重要，因为它们可能酷似转移性黑色素瘤。
