Central Laboratory of Pathology, Hôpital Pasteur, University of Nice, Nice, France.
Acta Derm Venereol. 2022 Jan 5;102:adv00628. doi: 10.2340/actadv.v101.546.
Pleomorphic onychomatricoma is a rare condition mimicking malignant neoplasms. Given its rarity, the diagnostic and prognostic criteria of this condition are not well established. The aim of this study was to characterize a series of 6 cases of pleomorphic onychomatricoma. In 3 cases the submitting clinical diagnosis was subungual squamous cell carcinoma. For all 6 cases, nail clipping showed typical features of onychomatricoma as a free-edge thickening and pitting of the nail plate with an additional feature of projecting line pattern. Pleomorphic onychomatricoma was diagnosed based on moderate-severe cytological atypia, yet degenerative-appearing with multinucleation or smudged chromatin, no mitotic activity or necrosis, and a Ki67 proliferative index inferior to 5% overall. Other finding s included epithelioid multinucleated cells with deeply eosinophilic cytoplasm mimicking epithelioid malignant cells, overexpression of Ki67 and p53 on atypical cells and diffuse expression of p16. This study describes additional criteria in pleomorphic onychomatricoma, permitting a wider recognition in order to avoid inappropriate treatment.
多形性甲床瘤是一种罕见的疾病，类似于恶性肿瘤。鉴于其罕见性，该疾病的诊断和预后标准尚未得到很好的确定。本研究的目的是描述 6 例多形性甲床瘤的系列病例。在 3 例中，提交的临床诊断为甲下鳞状细胞癌。对于所有 6 例患者，指甲剪显示出典型的甲床瘤特征，包括游离缘增厚和甲板出现凹坑，同时还具有突出的线状模式。多形性甲床瘤的诊断依据是中度至重度细胞学异型性，但表现为退行性改变，具有多核、模糊染色质，无有丝分裂活性或坏死，Ki67 增殖指数总体低于 5%。其他发现包括具有深嗜酸性细胞质的上皮样多核细胞，类似于上皮样恶性细胞，在异型细胞上过度表达 Ki67 和 p53 以及弥漫性表达 p16。本研究描述了多形性甲床瘤的其他标准，以便更广泛地识别，从而避免不适当的治疗。
