Dermatology Department at Hospital Universitario Fundación Alcorcón.
Dermatopathology Department at Hospital Universitario Fundación Alcorcón, Calle Budapest 1, 28922. Alcorcón, Madrid, Spain.
Eur J Dermatol. 2024 Oct 1;34(5):490-496. doi: 10.1684/ejd.2024.4747.
Lentigo maligna (LM) often poses a diagnostic challenge due to its clinical and dermoscopic mimicry of benign lesions, leading to delayed diagnosis. Focal areas of reticular disruption have been described as one of the earliest dermoscopic signs observed. To describe a novel dermoscopic sign in LM, namely the presence of a parallel pigmented network. Case series of 22 histopathologically-proven LM and lentigo maligna melanoma (LMM), diagnosed between 2018 and 2023, at a tertiary centre. All lesions showed a parallel network upon dermoscopy, in the form of parallel reticular lines, light or dark brown in colour, not emanating from the follicle, with an asymmetrical distribution. Reflectance confocal microscopy (RCM) images were reviewed to correlate these areas. The median age of patients was 73 years old. The majority of lesions were in situ (91%) and extrafacial (82%). Lesions showed minimal signs of atypia other than a parallel network and mostly focal erased areas (100%), followed by perifollicular linear projections (18%) and asymmetrical follicular pigmentation (18%). On RCM, focally areas correlated with atypical junctional thickenings distributed in a parallel fashion (100%) and mitochondria-like structures (23%). Most cases (88%) showed atypical cells in the epidermis, mostly in the form of isolated dendritic cells (41%). Parallel network emerges as a potential dermoscopic sign associated with LM. We hypothesize that in early stages of LM transformation, disruption of the reticular network manifests as parallel lines and/or radial perifollicular lines. Validation with larger studies is warranted.
恶性雀斑样痣（LM）常因其临床和皮肤镜表现类似于良性病变而导致诊断延迟，从而带来诊断挑战。网状结构中断的局灶性区域已被描述为最早观察到的皮肤镜下征象之一。为了描述 LM 中的一种新的皮肤镜下征象，即存在平行色素网络。对 2018 年至 2023 年期间在一家三级中心经组织病理学证实的 22 例 LM 和恶性雀斑样黑素瘤（LMM）的病例系列进行了研究。所有病变在皮肤镜下均表现为平行网络，呈平行的网状线，颜色为浅棕色或深棕色，并非从毛囊发出，分布不对称。回顾反射共聚焦显微镜（RCM）图像以相关联这些区域。患者的中位年龄为 73 岁。大多数病变位于原位（91%）和非面部（82%）。除了平行网络外，病变显示出最小的非典型性迹象，主要是局灶性擦除区（100%），其次是毛囊周围线性突出（18%）和不对称性毛囊色素沉着（18%）。在 RCM 上，局灶性区域与呈平行方式分布的非典型交界增厚（100%）和类似线粒体的结构（23%）相关。大多数病例（88%）显示表皮中有不典型细胞，主要形式为孤立的树突状细胞（41%）。平行网络是一种与 LM 相关的潜在皮肤镜下征象。我们假设在 LM 转化的早期阶段，网状结构的中断表现为平行线和/或放射状毛囊周围线。需要更大的研究来验证。
