Ogita Azusa, Ansai Shin-Ichi
Division of Dermatology and Dermatopathology, Nippon Medical School Musashi Kosugi Hospital, Kawasaki 211-8533, Japan.
Diagnostics (Basel). 2021 Oct 7;11(10):1848. doi: 10.3390/diagnostics11101848.
We present histopathological criteria for diagnosing keratoacanthoma (KA). In KA, four histological stages are recognized, which are the early/proliferative stage, well-developed stage, regressing stage and regressed stage. In diagnosing KA, we emphasize that KA consists of the proliferation of enlarged pale pink cells with ground glass-like cytoplasm without nuclear atypia, other than crateriform architecture. KA sometimes exhibits malignant transformation within the lesions. We describe the characteristics of benign and malignant epithelial crateriform tumors that should be differentiated from KA. We also present the data of histopathological diagnosis of lesions clinically diagnosed as KA, its natural course and related lesions after partial biopsy, and incidence of crateriform epithelial neoplasms. Based on these data, we recommend complete excision of the lesion when KA is clinically suspected, especially when the lesion is located on a sun-exposed area of an elderly patient. If complete excision is impossible, partial excision of a sufficient specimen with intact architecture is required. In such a case, however, careful investigation after biopsy will be needed, even if the histopathological diagnosis is KA, because there is some possibility that a conventional SCC lesion remains in the residual tissue.
我们提出了诊断角化棘皮瘤（KA）的组织病理学标准。在KA中，可识别出四个组织学阶段，即早期/增殖期、成熟发展期、消退期和消退后期。在诊断KA时，我们强调，除火山口样结构外，KA由具有毛玻璃样细胞质的增大淡粉色细胞增殖组成，无核异型性。KA有时在病变内发生恶性转化。我们描述了应与KA相鉴别的良性和恶性上皮性火山口样肿瘤的特征。我们还展示了临床诊断为KA的病变的组织病理学诊断数据、其自然病程以及部分活检后的相关病变，以及火山口样上皮性肿瘤的发病率。基于这些数据，我们建议在临床怀疑为KA时，尤其是病变位于老年患者暴露于阳光下的部位时，应完整切除病变。如果无法完整切除，则需要切除具有完整结构的足够标本。然而，在这种情况下，即使组织病理学诊断为KA，活检后也需要仔细检查，因为残留组织中仍有可能存在传统的鳞状细胞癌（SCC）病变。
