Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
Br J Dermatol. 2014 Jul;171(1):48-54. doi: 10.1111/bjd.12781. Epub 2014 May 22.
Amelanotic melanoma represents a diagnostic challenge both clinically and dermoscopically. Few studies based on case series have explored the possibility of using reflectance confocal microscopy (RCM) to diagnose amelanotic melanoma.
To validate a new confocal feature, named hyporeflective pagetoid cells (HPCs), for the diagnosis of amelanotic melanoma.
A group of 20 amelanotic melanomas and a control population of nonpigmented melanocytic naevi (10), hypo/nonpigmented nonmelanocytic lesions (20) and pigmented melanomas (20), imaged by RCM, were retrospectively evaluated. The presence of HPCs and other diagnosis-specific confocal features was assessed and correlated with histopathology.
HPCs were present, and usually abundant, in the majority of amelanotic melanomas (85%). As expected, they were also observed in Spitz naevi. On histopathology, they were correlated with pagetoid infiltration of hypomelanotic melanocytes in all melanocytic lesions. Few nonmelanocytic lesions (three squamous cell carcinomas, two seborrhoeic keratoses and one basal cell carcinoma) showed the presence of HPCs. In these cases, they corresponded to enlarged or dyskeratotic keratinocytes by histopathology.
The identification of HPCs in the epidermis is a new parameter that is frequently found in amelanotic melanoma. Possible confounders are represented by atypical keratinocytes that can be present in nonmelanocytic lesions. However, the whole architecture and the presence of additional diagnostic criteria should be considered in order to obtain a correct diagnosis.
无色素性黑素瘤在临床和皮肤镜下均具有诊断挑战性。少数基于病例系列的研究探讨了使用反射共聚焦显微镜（RCM）诊断无色素性黑素瘤的可能性。
验证一种新的共聚焦特征，即低反射性派杰样细胞（HPCs），用于诊断无色素性黑素瘤。
回顾性评估了一组 20 例无色素性黑素瘤和一个非色素性黑素细胞痣（10 例）、低色素/非色素性非黑素细胞病变（20 例）和色素性黑素瘤（20 例）的 RCM 图像。评估了 HPCs 及其他诊断特异性共聚焦特征的存在，并与组织病理学相关联。
HPCs 存在于大多数无色素性黑素瘤（85%）中，通常很丰富。如预期的那样，它们也存在于 Spitz 痣中。在组织病理学上，它们与所有黑素细胞病变中低色素性黑素细胞的派杰样浸润相关。少数非黑素细胞病变（3 例鳞状细胞癌、2 例脂溢性角化病和 1 例基底细胞癌）显示 HPCs 的存在。在这些病例中，它们与组织病理学上的增大或角化不良的角质形成细胞相对应。
表皮中 HPCs 的鉴定是无色素性黑素瘤中经常发现的一个新参数。可能的混杂因素是存在于非黑素细胞病变中的非典型角质形成细胞。然而，为了获得正确的诊断，应该考虑整个结构和其他诊断标准的存在。
