Pepe Carla Antonella, Lombardi Mara, Cortelazzi Chiara, Aimi Francesca, Ricci Roberto, Taglia Maurizio, Santoro Silvia, Zucchi Alfredo, Zambito-Spadaro Fabio, De Panfilis Giuseppe, Fabrizi Giuseppe
Parma University.
Acta Biomed. 2014 May 9;85(1):60-3.
Pigmented epitheliod melanocytoma (PEM) is a uncommon melanocytoma with unique histopathological features and possibly with a favourable prognosis, because, although sentinel lymph-node metastases may occur, in the great majority of cases described up to now there is no spread beyond regional lymph-nodes. The nature of PEM, its biologic behaviour and its relationships to naevi and melanoma, however, remain to be clearly established, and several Authors suggest that further cases of PEM with long follow-up should be published, in order to better assess the biologic/prognostic characteristics of PEM.
We report a new case of PEM, dealing with an oval, regularly marginated, darkly pigmented, asymptomatic nodule. The dermoscopic pattern showed a homogeneous blue-black pigmentation, without any other dermoscopic sign. The histopathologic analysis showed both isolated and nested oval melanocytes at the junctional level, and a mixture of epitheliod and spindle melanocytes, heavily pigmented, together with numerous melanophages in the dermis, with tendency to periadnexal distribution; cellular atypia was pronounced, but only occasional mitoses were identified in the superficial dermis. After a 4-year follow-up period after excision, no persistent lesion or metastases occurred.
The present case suggests that PEM has a distinct histopathologic/diagnostic identity among melanocytic tumours. Although the up-to-now favourable outcome, however, our patient needs a large period of observation, and further studies with long follow-up are needed to better define the biologic/prognostic identity of PEM.
色素性上皮样黑素细胞瘤（PEM）是一种罕见的黑素细胞瘤，具有独特的组织病理学特征，可能预后良好，因为尽管可能发生前哨淋巴结转移，但在目前报道的绝大多数病例中，病变未超出区域淋巴结范围。然而，PEM的本质、生物学行为及其与痣和黑色素瘤的关系仍有待明确，几位作者建议应发表更多长期随访的PEM病例，以便更好地评估PEM的生物学/预后特征。
我们报告一例新的PEM病例，该病例为一个椭圆形、边缘规则、色素沉着深且无症状的结节。皮肤镜表现为均匀的蓝黑色色素沉着，无其他皮肤镜表现。组织病理学分析显示在交界水平既有孤立的也有巢状的椭圆形黑素细胞，真皮内有上皮样和梭形黑素细胞的混合，色素沉着严重，同时真皮内有大量噬黑素细胞，倾向于围绕附属器分布；细胞异型性明显，但仅在真皮浅层发现偶尔的核分裂象。切除后经过4年的随访期，未出现持续性病变或转移。
本病例提示PEM在黑素细胞肿瘤中具有独特的组织病理学/诊断特征。尽管目前预后良好，但我们的患者仍需要长期观察，并且需要进一步进行长期随访研究，以更好地明确PEM的生物学/预后特征。
