Ríos-Viñuela E, Nájera-Botello L, Requena L, Nagore E, Requena C
Servicio de Dermatología, Fundación Instituto Valenciano de Oncología, Valencia, España.
Servicio de Anatomía Patológica, Hospital Universitario Puerta de Hierro, Madrid, España.
Actas Dermosifiliogr (Engl Ed). 2021 Jan 16. doi: 10.1016/j.ad.2020.12.004.
Both dermatologists and pathologists sometimes find daunting the evaluation of melanonychia (especially subungual melanocytic lesions) because of the fear of performing nail surgery due to the risk of dystrophy, difficulties processing and interpreting nail biopsy specimens, and a general lack of experience in the field. Nevertheless, mastery of nail biopsy techniques, correct processing and orientation of specimens, and familiarity with the histologic particularities of the nail apparatus can attenuate the undoubted complexity and facilitate the tasks involved. Longitudinal excision is the biopsy technique that ensures the simplest histologic interpretation, and it is associated with a low risk of nail dystrophy when performed correctly. Clinical and epidemiological data are crucial. Subungual melanoma in childhood, for instance, is very rare and even lesions with atypical clinical and/or histologic features are probably benign. The presence of suprabasal melanocytes and other findings that would suggest malignancy at other sites are considered normal in the nail apparatus. Subungual melanoma shows a lentiginous pattern in the early stages of disease, and detection of an inflammatory infiltrate accompanying atypical lentiginous subungual lesions would appear to be one of the first diagnostic findings.
皮肤科医生和病理科医生有时会觉得评估甲下色素沉着（尤其是甲下黑素细胞性病变）颇具挑战性，原因在于担心因营养不良风险而进行指甲手术、处理和解读指甲活检标本存在困难，以及该领域普遍缺乏经验。然而，掌握指甲活检技术、正确处理标本并确定其方向，以及熟悉甲器的组织学特性，能够减轻这一无疑存在的复杂性，并便于开展相关工作。纵向切除是能确保组织学解读最为简单的活检技术，正确实施时其导致指甲营养不良的风险较低。临床和流行病学数据至关重要。例如，儿童期甲下黑色素瘤极为罕见，即便具有非典型临床和/或组织学特征的病变可能也是良性的。基底层上黑素细胞的存在以及其他在其他部位提示恶性的发现，在甲器中被视为正常情况。甲下黑色素瘤在疾病早期呈雀斑样模式，伴随非典型雀斑样甲下病变出现炎症浸润似乎是最早的诊断发现之一。
