Keratoacanthoma and other types of squamous cell carcinoma with crateriform architecture: Classification and identification

The terminology and classification of keratoacanthoma (KA) and other types of squamous cell carcinoma (SCC) with crateriform architecture have not been clarified. The study evaluated the clinicopathological features of 41 nodular (exo‐endophytic) SCC lesions with a central keratin‐filled crater, including KA (well‐developed stage). The lesions were histopathologically classified into six categories: (i) KA (well‐developed stage) (27 lesions); (ii) KA‐like SCC (three lesions); (iii) KA with malignant transformation (three lesions); (iv) infundibular SCC (crateriform) (four lesions); (v) crateriform SCC arisen from actinic keratosis (three lesions); and (vi) crateriform Bowen's disease (one lesion). The true characteristics of KA‐like SCC remain unresolved, but there are three possibilities, namely, that it is one step in the evolution of KA, it is a borderline lesion between KA and invasive SCC, or it is one form of “KA with malignant transformation”. KA, KA‐like SCC, KA with malignant transformation and infundibular SCC (crater form) are considered to be hair follicle‐related neoplasms. In contrast, crateriform SCC arisen from actinic keratosis and crateriform Bowen's disease are SCC, which are not related either to the hair follicles or KA. From an etiological standpoint, the presented lesions in these six categories are considered to be mixed up due to the similarity of crateriform architecture between the various types of lesions. However, the information provided in this report is intended to help physicians to make an accurate differential diagnosis of these conditions in clinical practice. The present study provides an opportunity to standardize the terminology for KA and related neoplasms.     

眼外型皮脂腺癌一例

患者,女,27岁。因头皮斑块2个月就诊。组织病理示：肿瘤呈水平及垂直方向生长,累及表皮、真皮至脂肪组织浅层。可见细胞异型性及病理性核分裂相。肿物扩大切除术后再次行组织病理示表皮内肿瘤细胞呈paget病样生长,一侧切缘仍有肿瘤细胞残留。免疫组织化学：肿瘤细胞EMA(+)、AR(-),CAE(-)、ER(-),Ki67增殖指数为30%。诊断：皮脂腺癌。拟再次行切除术并辅以放疗或化疗。     

泛发性汗孔角化症合并枕部巨大鳞癌一例

患者,女,46岁。全身角化性丘疹30年余,头皮破溃1年余。皮肤科情况：躯干四肢褐色斑块,部分中央萎缩;枕部可见18 cm×9 cm溃疡。枕部皮损组织病理检查示条索状异型肿瘤细胞;免疫组化示鳞癌。上肢皮损组织病理检查：多个角化不全柱。诊断：泛发性汗孔角化症合并枕部巨大鳞癌。给予放疗,效果可。     

Crater/ulcerated form of infundibular squamous cell carcinoma: A possible distinct entity as a malignant (or high‐grade) counterpart to keratoacanthoma

Follicular squamous cell carcinoma (SCC) with infundibular differentiation includes the common and crater forms of infundibular SCC. We previously considered the crater/ulcerated infundibular SCC to be a progressive condition of the common form and histopathologically studied an additional five cases of the crater/ulcerated infundibular SCC, the results of which suggested the following characteristic histopathological features and possible developmental process in this type of SCC: (i) a considerable number of continuous hyperplastic follicular infundibula, which may develop at the beginning of the disease; (ii) hyperplastic infundibula exhibiting an abrupt or gradual transition to the SCC component, which frequently change relative to the neoplastic infundibular canal; and (iii) the presence of multiple sites of branching of the neoplastic infundibular canals and/or complete involvement of large cysts in the neoplastic process over the center of the lesion, resulting in ulceration. Based on these histopathological findings, we considered that crater/ulcerated infundibular SCC involve a considerable number of continuous follicular infundibula from the start, although some cases may develop from the common form. We also emphasize the possible aggressive biological behavior of the crater/ulcerated form. Keratoacanthoma (KA) is a unique, benign or borderline malignant neoplasm exhibiting follicular (infundibular/isthmic) differentiation characterized by the involvement of continuous follicular infundibula in multiples. From this standpoint, we consider that crater/ulcerated infundibular SCC is possibly related to KA in terms of histogenesis and is a malignant (or high‐grade) counterpart of KA.     

Extraocular sebaceous carcinoma in situ: report of three cases and review of the literature

Extraocular sebaceous carcinoma is a rare neoplasm. Purely in situ extraocular sebaceous carcinoma is extremely rare and somewhat controversial. Review of the literature reveals only three reported cases, two of which involved the head and neck and one the arm. The ones on the head and neck arose in association with an actinic keratosis. We report three cases of extraocular sebaceous carcinoma in situ and describe the first report of immunoperoxidase screening for mismatch repair proteins in such tumors.     

Merkel细胞癌合并原位鳞状细胞癌一例并文献复习

Merkel细胞癌是一种罕见的、具有高度侵袭性的皮肤神经内分泌癌,好发于老年人的日光暴露部位,尤其是头颈部(41%～50%),其次是四肢(32%～38%)。Merkel细胞癌可与鳞状细胞癌、鲍温病、基底细胞癌等皮肤肿瘤合并发生。我们报道一例发生在非光暴露部位的Merkel细胞癌合并原位鳞状细胞癌,并对相关文献进行复习。     

Eruptive keratoacanthoma and squamous cell carcinoma complicating imiquimod therapy: response to oral acitretin

An 87-year-old woman with eruptive keratoacanthomas complicating recent imiquimod therapy is presented. Lesions developed both at and distal to the treatment site. She responded well to 8 weeks of oral acitretin with resolution of most lesions and no recurrence at 6 months post treatment. A remaining lesion was excised and found to be a well-differentiated squamous cell carcinoma. Keratoacanthoma and squamous cell carcinoma should be considered in any patient developing rapidly growing keratotic nodules in association with recent imiquimod therapy. The aetiology and treatment of eruptive keratoacanthomas is briefly discussed.     

角化棘皮瘤和皮肤鳞状细胞癌bcl—2和Nm23癌基因蛋白表达的比较研究

目的：通过研究分析bcl-2和Nm23蛋白在角化棘皮瘤（KA）和皮肤鳞状细胞癌（SCC）中的表达和临床意义。探寻两病的鉴别标志。方法：应用免疫组化技术（SABC）对11例KA，28例SCC进行了检测。结果：bcl-2和Nm23蛋白在KA和SCC中的表达经统计学分析无显著性意义。结论：bcl-2和Nm23癌基因均参与了KA和SCC的发病过程，但都不能作为KA和SCC的鉴别标志。     

Possible spontaneous regression of a metastatic lesion of keratoacanthoma-like squamous cell carcinoma in a regional lymph node

We report herein a case of keratoacanthoma-like squamous cell carcinoma in an 82-year-old male that showed regional lymph node metastasis followed by self-regression of the metastatic lesion. This case is consistent with the previously reported observation that tumors compatible with the clinical features of keratoacanthoma may have malignant biological potential, however, it also demonstrates that even metastatic lesions may exhibit self-regression similar to that observed for primary lesions. Despite the view that keratoacanthoma-like squamous cell carcinoma may represent a variant of squamous cell carcinoma, occasionally it undergoes a unique clinical course.     

长期被误诊为甲沟炎的甲下鳞状细胞癌一例

甲下鳞状细胞癌是一种罕见的疾病,常常被延迟诊断或误诊,平均延迟诊断时间为62.4个月,误诊率高达78.9％.本文报道一例误诊为甲沟炎2年的甲下鳞状细胞癌患者.患者,男,49岁.右手第5指外侧缘起皮疹伴疼痛2年.皮损组织病理示高分化鳞状细胞癌.于局麻下行皮肤恶性肿瘤切除术及游离皮瓣移植术.术后恢复良好,随访半年无复发.     

角化棘皮瘤与高分化鳞状细胞癌细胞凋亡及凋亡基因bcl-2和bax比较研究

目的：探讨角化棘皮瘤与皮肤高分化鳞癌在细胞凋亡方面的差异。方法：用脱氧核苷酰转移酶介导的ｄ－ＵＴＰ生物素缺口末端标记技术，原位检测了ＫＡ和ｗＳＣＣ的凋亡细胞。用免疫组化研究技术研究了皮损部位与细胞凋亡有关ｂａｘ和ｂｃｌ－２的基因产物的表达。结果：凋亡细胞在ＫＡ发生率为８０％；在ｗＳＣＣ也为８０％。     

Epidemiology of cutaneous sebaceous carcinoma

There has been uncertainty about the demographics and anatomical distribution of cutaneous sebaceous carcinoma. This study aims to investigate these uncertainties by analysing data from various countries. Data were obtained from cancer registries of the United States, England, Norway and Taiwan, and incidence rates were calculated with uniform age‐adjustment. sebaceous carcinoma was more commonly reported in males than females in white populations, whereas the inverse was true in Taiwan. Ocular sebaceous carcinoma was more commonly reported in females than males in all populations, despite male predominance in white populations. The majority (approx. 70–90%) occurred on head and neck in Asians and whites. Age‐adjusted incidence rate (to the 2000–2025 WHO World Standard Population) ranged from 0.07 to 0.18 per 100 000 person‐years and was not higher in Taiwanese than in white populations.     

Histopathological diagnosis of epithelial crateriform tumors: Keratoacanthoma and other epithelial crateriform tumors

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.     

性病性淋巴肉芽肿合并皮肤鳞状细胞癌一例

患者男,53岁,冠状沟增生物2年,腹股沟包块红肿、疼痛、破溃2月余。体检：双侧腹股沟淋巴结红肿约2 cm × 1.5 cm,质硬,触痛,右侧腹股沟肿大淋巴结中心波动,其上见多处破溃及黄白色脓性分泌物流出,如喷水壶状。多个肿大或破溃淋巴结被腹股沟韧带分隔,形成明显的沟槽征。冠状沟两侧可见1 cm × 2 cm不规则疣状增生,质硬,表面角化。龟头系带处红肿,有波动,并有破溃伴黄白色脓液渗出,右侧阴囊肿胀。龟头系带处分泌物及左右侧腹股沟穿刺液多次真菌培养阴性,细菌培养阴性,抗酸染色阴性,沙眼衣原体培养初次为阴性,衣原体内源性质粒PCR检测阳性,omp1-限制性片段长度多态性（RFLP）分型为L3型。Western印迹示血清沙眼衣原体主要外膜蛋白（MOMP）抗体阳性,多形外膜蛋白H（PmpH）抗体 > 1 ∶ 800,衣原体多代培养阳性。右腹股沟疣状增生处活检示皮肤高分化鳞状细胞癌。诊断：性病性淋巴肉芽肿合并皮肤鳞状细胞癌。     

梭形细胞鳞状细胞癌一例

患者女,62岁.下唇斑块伴轻度瘙痒2年就诊.2年前无明显诱因下唇中部出现一硬化、增厚的黄豆大小斑疹,轻度瘙痒,少许片状脱屑,无糜烂、渗液及结痂.     

无肌炎性皮肌炎并发鳞状细胞癌致上腔静脉综合征1例

报告1例伴发上腔静脉综合征的无肌炎性皮肌炎。患者男,61岁。反复双眼睑、面部、胸部紫红斑近2年,无明显肌肉症状,且逐渐出现上腔静脉回流受阻的表现,经实验室、CT及淋巴结组织病理学检查确诊为无肌炎性皮肌炎并发纵隔鳞状细胞癌致上腔静脉综合征。     

PD-L1在皮肤鳞状细胞癌及角化棘皮瘤中的表达

目的：检测PD-L1在皮肤鳞状细胞癌（cSCC）及角化棘皮瘤（KA）中的表达,分析PD-L1与cSCC分化程度的相关性。方法：免疫组化染色检测PD-L1在cSCC及KA中表达水平。结果：共检测56例cSCC患者和32例KA患者标本，PD-L1在cSCC组和KA组中的阳性率分别为66.07%和62.50%，均显著高于正常对照组（9.38%）（Ps＜0.01）。PD-L1阳性率在cSCC与KA组的差异没有统计学意义（P＞0.05）。PD-L1的表达强度与cSCC的分化程度呈负相关（P＜0.05）。结论：PD-L1不能作为区分cSCC与KA的指标。PD-L1的表达强度与cSCC分化程度呈负相关。     

皮脂腺痣并发乳头状汗管囊腺瘤及基底细胞癌

报告1例皮脂腺痣患者,曾接受数次肿块平皮面削除手术后复发,全部皮损经组织病理学检查,病理诊断为皮脂腺痣并发乳头状汗管囊腺瘤及基底细胞癌.故皮脂腺痣皮损应彻底切除,并送组织病理检查,而不宜简单进行削平.     

Natural course of keratoacanthoma and related lesions after partial biopsy: Clinical analysis of 66 lesions

There is some confusion regarding the classification of keratoacanthoma (KA) and related lesions that have crateriform architecture. We examined the clinical courses of 66 KA lesions and related lesions after a partial biopsy to clarify the nosological concept of KA. We histopathologically classified these lesions into five types: (i) KA at various stages (53 lesions); (ii) KA‐like squamous cell carcinoma (SCC) (3 lesions); (iii) KA with malignant transformation (3 lesions); (iv) infundibular SCC (5 lesions); and (v) crateriform SCC arising from solar keratosis (2 lesions). We analyzed the clinical course in each group. The regression rate of KA was 98.1% and that of KA‐like SCC/KA with malignant transformation was 33.3%. No regression was observed in either infundibular SCC or crateriform SCC arising from solar keratosis. Thus, KA is a distinct entity that should be distinguished from other types of SCC with crateriform architecture based on the high frequency of regression. The regression rate of 33.3% in KA‐like SCC/KA with malignant transformation indicated that KA lesions with an SCC component still have the potential for regression. However, this result also indicated that KA is biologically unstable, and some KA tend to evolve into conventional SCC with a gradual loss of the capacity for the spontaneous regression. Infundibular SCC and crateriform SCC arising from solar keratosis are fundamentally different from KA, not only according to the histopathological findings but also based on the biological properties.