Abstract：
BACKGROUND: Inverted follicular keratosis (IFK) is a benign cutaneous epithelial tumor typically presenting as a small papule on the head and neck. We have encountered deep endophytic tumors on genital skin with some characteristics of IFK but also atypical features, raising concern for squamous cell carcinoma (SCC).
METHODS: Four such tumors were identified in our database. Histopathologic analysis and ancillary studies were performed.
RESULTS: All patients were young women who presented with a solitary 0.5-1.0 cm lesion on the vulva, perineum, or inner buttock. Each showed a squamous proliferation arising from the epidermis, with endophytic growth that was deep and bulbous but not infiltrative. The tumor lobules contained eosinophilic keratinocytes, forming numerous squamous eddies. Small irregular spaces and dyskeratotic cells were frequently found. Nuclear pleomorphism was minimal to absent. All demonstrated wild-type p53 expression and lack of p16 block positivity. In situ hybridizations for human papillomavirus were negative. None of the three cases with follow-up data showed evidence of recurrence.
CONCLUSIONS: The absence of infiltrative growth or significant pleomorphism, the presence of numerous squamous eddies, the reassuring immunoprofile, and the lack of evidence of recurrence support a variant of IFK and speak against SCC. We propose the term \"proliferating IFK\" to highlight the florid squamous proliferation. Recognition of this unusual variant would avoid overdiagnosis of SCC.
METHODS: Four such tumors were identified in our database. Histopathologic analysis and ancillary studies were performed.
RESULTS: All patients were young women who presented with a solitary 0.5-1.0 cm lesion on the vulva, perineum, or inner buttock. Each showed a squamous proliferation arising from the epidermis, with endophytic growth that was deep and bulbous but not infiltrative. The tumor lobules contained eosinophilic keratinocytes, forming numerous squamous eddies. Small irregular spaces and dyskeratotic cells were frequently found. Nuclear pleomorphism was minimal to absent. All demonstrated wild-type p53 expression and lack of p16 block positivity. In situ hybridizations for human papillomavirus were negative. None of the three cases with follow-up data showed evidence of recurrence.
CONCLUSIONS: The absence of infiltrative growth or significant pleomorphism, the presence of numerous squamous eddies, the reassuring immunoprofile, and the lack of evidence of recurrence support a variant of IFK and speak against SCC. We propose the term \"proliferating IFK\" to highlight the florid squamous proliferation. Recognition of this unusual variant would avoid overdiagnosis of SCC.
摘要：
背景：内翻滤泡性角化病（IFK）是一种良性皮肤上皮肿瘤，通常表现为头颈部的小丘疹。我们在生殖器皮肤上遇到了一些具有IFK特征但也有不典型特征的深层内生肿瘤，引起对鳞状细胞癌（SCC）的关注。
方法：在我们的数据库中鉴定出4种这样的肿瘤。进行了组织病理学分析和辅助研究。
结果：所有患者均为年轻女性，外阴有0.5-1.0厘米的孤立性病变，会阴,或内臀部。每个都显示出表皮产生的鳞状增生，内生生长，深而球形，但不渗透。肿瘤小叶含有嗜酸性角质形成细胞，形成许多鳞状漩涡。经常发现小的不规则空间和生殖不良细胞。核多态性很少出现。所有都证明了野生型p53表达和缺乏p16阻断阳性。人乳头瘤病毒的原位杂交为阴性。有随访数据的三例病例均未显示复发证据。
结论：没有浸润性生长或明显的多态性，许多鳞状漩涡的存在，令人放心的免疫概况，缺乏复发的证据支持IFK的变体并反对SCC。我们提出术语“增殖IFK”来强调花状鳞状细胞增殖。识别这种不寻常的变异将避免SCC的过度诊断。
方法：在我们的数据库中鉴定出4种这样的肿瘤。进行了组织病理学分析和辅助研究。
结果：所有患者均为年轻女性，外阴有0.5-1.0厘米的孤立性病变，会阴,或内臀部。每个都显示出表皮产生的鳞状增生，内生生长，深而球形，但不渗透。肿瘤小叶含有嗜酸性角质形成细胞，形成许多鳞状漩涡。经常发现小的不规则空间和生殖不良细胞。核多态性很少出现。所有都证明了野生型p53表达和缺乏p16阻断阳性。人乳头瘤病毒的原位杂交为阴性。有随访数据的三例病例均未显示复发证据。
结论：没有浸润性生长或明显的多态性，许多鳞状漩涡的存在，令人放心的免疫概况，缺乏复发的证据支持IFK的变体并反对SCC。我们提出术语“增殖IFK”来强调花状鳞状细胞增殖。识别这种不寻常的变异将避免SCC的过度诊断。
