Ogita Azusa, Ansai Shin-Ichi, Misago Noriyuki, Anan Takashi, Fukumoto Takaya, Saeki Hidehisa
Division of Dermatology, Nippon Medical School Musashi Kosugi Hospital, Kawasaki, Japan.
Division of Dermatology, Nakao Clinic, Saga, Japan.
J Dermatol. 2016 Nov;43(11):1321-1331. doi: 10.1111/1346-8138.13390. Epub 2016 Apr 14.
Keratoacanthoma (KA) is a unique and distinct clinicopathological entity, although there is often confusion regarding its differentiation from other types of crateriform tumors. In this study, the clinicopathological features of 380 epidermal crateriform tumors with a central keratin plug were re-examined and the tumors were histologically classified into seven types: (i) crateriform verruca; (ii) crateriform seborrheic keratosis; (iii) KA; (iv) KA with a conventional squamous cell carcinoma (SCC) component (KA-like SCC and KA with malignant transformation); (v) crateriform Bowen's disease; (vi) crateriform SCC arising from solar keratosis; and (vii) crater form of infundibular SCC. Our study proved that incidence of SCC developing in KA lesions was 17.4%. The incidence rate differed depending on a patient's ages: 8.3% in patients less than 70 years of age and 24.3% in those aged 70 years and older. Nearly all of the malignant crateriform neoplasms (94.7%) occurred on sun-exposed areas. Lesions on the face included 138 KA (59.5%), 65 malignant crateriform neoplasms (28%) and 29 benign crateriform neoplasms (12.5%). We conclude that KA is not a variant of SCC, but a benign and frequently regressing proliferative lesion or borderline neoplasm, although there is the potential for SCC to arise within KA. Because the incidence of SCC developed in KA lesions and the incidence of other malignant crateriform neoplasms are higher in patients aged 70 years and older, KA-like lesions on sun-exposed areas over 70 should be assessed carefully in consideration of the potential risk of malignancy.
角化棘皮瘤（KA）是一种独特且明确的临床病理实体，尽管在其与其他类型火山口状肿瘤的鉴别上常常存在混淆。在本研究中，对380例具有中央角质栓的表皮火山口状肿瘤的临床病理特征进行了重新检查，并将这些肿瘤在组织学上分为七种类型：（i）火山口状疣；（ii）火山口状脂溢性角化病；（iii）KA；（iv）伴有传统鳞状细胞癌（SCC）成分的KA（KA样SCC和恶变的KA）；（v）火山口状鲍温病；（vi）由日光性角化病发展而来的火山口状SCC；以及（vii）漏斗状SCC的火山口状形态。我们的研究证明，KA病变中发生SCC的发生率为17.4%。发生率因患者年龄而异：70岁以下患者为8.3%，70岁及以上患者为24.3%。几乎所有恶性火山口状肿瘤（94.7%）都发生在阳光暴露部位。面部病变包括138例KA（59.5%）、65例恶性火山口状肿瘤（28%）和29例良性火山口状肿瘤（12.5%）。我们得出结论，KA不是SCC的一种变体，而是一种良性且常自行消退的增生性病变或交界性肿瘤，尽管KA内部有发生SCC的可能性。由于70岁及以上患者中KA病变发生SCC的发生率以及其他恶性火山口状肿瘤的发生率较高，对于70岁以上阳光暴露部位的KA样病变，应考虑到潜在的恶性风险进行仔细评估。
