黑色素瘤形态学和免疫表型的变化

Morphological and immunophenotypic variations in malignant melanoma

在黑色素瘤中能观察到多种细胞形态学特征、组织构型和基质的变化。黑色素瘤可以由大的多形性细胞或小细胞或梭形细胞组成 ,也可含有透明细胞、印戒细胞、假脂母细胞、横纹样细胞、浆细胞样细胞和气球细胞 ,在细胞质中存在各种各样的包涵体或吞噬物。细胞核可呈双核或多核或分叶核 ,可有核内包涵体 ,形成核沟或成角。组织构型的变化包括束状、漩涡状、巢状、小梁状、假腺样 /假乳头状 /假滤泡状、假玫瑰花样或中央脉管样。基质呈黏液样变或促纤维增生改变 ,极少呈假血管肉瘤改变、肉芽肿性炎症或伴破骨巨细胞反应。基质的血管可呈血管周细胞瘤样 ,血管球样血管增殖或血管周透明变性。黑色素瘤特异性标记物是S 10 0蛋白、NKIC3、HMB4 5、MelanA和酪胺酸酶 。

A variety of cytomorphological features, architectural patterns and stromal changes may be observed in malignant melanomas. Hence, melanomas may mimiccarcinomas, sarcomas, benign stromal tumours, lymphomas, plasmacytomas and germ cell tumours. Melanomas may be composed of large pleomorphic cells, small cells, spindle cells and may contain clear, signet-ring, pseudolipoblastic, rhabdoid, plasmacytoid or balloon cells. Various inclusions and phagocytosed material may be present in their cytoplasm. Nuclei may show bi- or multi-nucleation, lobation, inclusions, grooving and angulation. Architectural variations include fasciculation, whorling, nestion, trabeculation, pseudoglandular, pseudopapillary, pseudofollicular, pseudorosetting and angiocentric patterns. Mucoid or desmoplastic changes and very rarely pseudoangiosarcomatous change, granulomatous inflammation or osteoclastic giant cell response may be seen in the stroma. The stromal blood vessels may exhibit a haemangiopericytomatous pattern, proliferation of glomeruloid blood vessels and perivascular hyalinization. Occasionally, differentiation to nonmelanocytic structures (Schwannian, fibro/myofibroblastic, osteocartilaginous, smooth muscle, rhabdomyoblastic, ganglionic and ganglioneuroblastic) may be observed. Typically melanomas are S-100 protein, NKIC3, HMB45, Melan A and tyrosinase positive but some melanomas may exhibit an aberrant immunophenotype and may express cytokeratins, desmin, smooth muscle actin, CD68, CEA, EMA and VS38. Very rarely, neurofilament protein and GFAP positivity may be seen.