OBJECTIVES This study aims at the identification of the distribution of basal cell carcinomas (BCCs) in the auricle in correlation with the currently most credited sites of the embryonic fusion planes of the auricle. METHODS An overall number of 69 patients with 72 BCCs of the auricle were enrolled in the study over a period of 14 years, from June 2003 to October 2017. All the cases underwent medical preoperative digital photography and the specific location of each BCC was coded on an original full-size anatomical diagram of the auricle derived from the reports by Streeter, Wood-Jones, Park, Porter, and Minoux showing the currently most credited sites of the embryonic fusion planes arbitrarily featured as two 5-mm-wide ribbon-like areas: (1) the hyoid-mandibular fusion plane (HM-FP) running from the upper margin of the tragus toward the concha and then deflecting toward the lower margin of the tragus and (2) the free ear fold-hyoid fusion plane (FEFH-FP) running from the cranial-most portion of the helix to the mid-portion of the ascending helix. The latter fusion planes were comprehensively termed embryological fusion planes (EFP) while all of the remaining surface of the auricle was comprehensively termed non-fusion area (NFA). The surfaces of all of the latter areas were calculated using the ImageJ software. RESULTS According to our data, the greatest number of BCCs was observed within the currently most credited sites of the embryonic fusion planes of the auricle. The latter sites displayed a 12-fold increased tumor incidence in comparison with the remaining surface of the ear. CONCLUSIONS A correspondence between the sites of onset of BCCs and the sites of merging and/or fusion of embryonal processes was demonstrated in the auricle. Therefore, the latter sites might be considered as high-risk areas for the development of a BCC. Such an evidence provides further support to the hypothesis of an embryological pathogenesis of BCC.

中文翻译：

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基底细胞癌发病部位与耳廓胚胎融合平面的相关性。

目的 本研究旨在确定耳廓中基底细胞癌 (BCC) 的分布与目前最可信的耳廓胚胎融合平面部位相关。方法 在 2003 年 6 月至 2017 年 10 月的 14 年期间内，共有 69 名患有 72 个耳廓 BCC 的患者参加了该研究。所有病例均进行了术前医学数码摄影，每个 BCC 的具体位置被编码在来自 Streeter、Wood-Jones、Park、Porter 和 Minoux 的报告的原始全尺寸耳廓解剖图，显示了胚胎融合平面目前最可信的位置，任意特征为两个 5 毫米宽的带状领域：(1) 舌骨-下颌骨融合平面 (HM-FP) 从耳屏上缘向耳甲延伸，然后向耳屏下缘偏转； (2) 游离耳襞-舌骨融合平面 (FEFH- FP）从螺旋的最头部分延伸到上升螺旋的中间部分。后一种融合平面被统称为胚胎融合平面（EFP），而耳廓的所有剩余表面被统称为非融合区（NFA）。使用 ImageJ 软件计算所有后者区域的表面。结果根据我们的数据，在目前最可信的耳廓胚胎融合平面内观察到的BCC数量最多。与耳朵的其余表面相比，后一个部位的肿瘤发病率增加了 12 倍。结论 在耳廓中证实了 BCC 的发病部位与胚胎过程的合并和/或融合部位之间的对应关系。因此，后者可能被视为发展 BCC 的高风险区域。这样的证据进一步支持了 BCC 胚胎发病机制的假设。