Onychomatricoma mimicking subungual melanoma and Bowen’s disease
Onychomatricoma mimicking subungual melanoma and Bowen’s disease
复制标题
甲母瘤模仿甲下黑色素瘤和鲍文氏病
DOI：
10.1002/cia2.12205
复制
发表时间：
2021
影响因子：
1
通讯作者：
S. Motegi
中科院分区：
文献类型：
--
作者：
Y. Kuriyama;A. Shimizu;A. Tamura;S. Motegi
甲基质瘤是甲基质的一种良性肿瘤，通常表现为淡黄色增厚的甲板和近端裂状出血，但有时也表现为纵向黑甲。纵向黑甲癣已在多种疾病中得到证实。虽然甲真菌病是常见的，但恶性疾病如甲下黑色素瘤和Bowen病也应加以鉴别。我们在此报告一个类似于甲下黑色素瘤和Bowen病的色素性甲母细胞瘤病例。一名53岁的日本男性就诊于我们的皮肤科诊所，他有2年的趾甲色素沉着史（图1A）。体格检查发现右大趾甲内侧边缘有深棕色色带。钉板受累部位增厚粗糙。耳镜检查显示在褐色均匀色带上有纵向平行的白线（图1B）。氢氧化钾（KOH）检查真菌呈阴性。怀疑诊断为甲下黑色素瘤或Bowen病，行切除活检。取下的甲板近端组织病理学检查显示多发深内陷，充满指状上皮增生（图1C）。指状上皮顶端有较厚的角化带。切除的甲基质乳头状肿瘤显示纤维上皮突起，间质中梭形细胞增生（图1D， E）。免疫组化检查显示，纤维间质中CD10和CD34阳性细胞增生（图1F）。此外，S100和Melan A染色显示上皮内散在黑色素细胞，无明显增殖（图1G）。使用人乳头瘤病毒（HPV）的共识引物L1C1/L1C2和GP5(+)/GP6（+）进行PCR分析，结果为阴性（数据未显示）根据这些临床病理特征，我们诊断为甲母细胞瘤。随访5个月未见复发（图1H）。甲基质瘤是一种良性甲基质瘤，Baran和Kint于1992年首次发现。Di Chiacchio等人总结了30例甲原色瘤，其主要临床特征为甲厚增加、裂状出血、黄斑病和甲横向弯曲。然而，纵向黑甲癣的发生率较低色素性甲原瘤保留了典型甲原瘤的组织病理学特征，即上皮内陷，充满v形角化带，纤维间质丰富，甲板增厚，空腔被上皮乳头状突起占据。免疫组化：间质细胞CD10、CD34阳性这些结果与我们的案例一致。色素性甲基质瘤的鉴别诊断包括甲真菌病、外伤性甲下血肿、Bowen病和甲下黑色素瘤透过半透明的角质层可见色素沉着，如我们的病人，显示为假哈钦森征虽然Hutchinson征象在黑色素瘤中很常见，但在甲鳞状细胞癌中比在甲基质瘤中更常观察到局部角化过度、黑点、游离边缘指甲凹陷和发夹样血管我们的病例也类似于经常与高危HPV感染相关的甲下鲍恩病由于色素性甲母细胞瘤经常伪装成甲下黑色素瘤和Bowen病，我们应该记住这种罕见但特殊的情况
Dear Editor, Onychomatricoma is a benign tumor of the nail matrix, usually shows a yellowish and thickened nail plate and proximal splinter hemorrhage but sometimes present with longitudinal melanonychia. Longitudinal melanonychia has been demonstrated in diverse diseases. While onychomycosis is the common, malignant diseases such as subungual melanoma and Bowen's disease should also be differentiated. We herein report a case of pigmented onychomatricoma that mimics subungual melanoma and Bowen's disease. A 53yearold Japanese man visited our dermatology clinic with a 2year history of toenail pigmentation (Figure 1A). Physical examination revealed a dark brown pigmented band on the medial edge of the right great toenail. The involved area of the nail plate was thickened and rough. Onychoscopy showed longitudinal parallel white lines on the band of brownish homogenous coloration (Figure 1B). A potassium hydroxide (KOH) examination for fungi was negative. Under the suspected diagnosis of subungual melanoma or Bowen's disease, an excisional biopsy was performed. Histopathological examination of the proximal portion of removed nail plate showed multiple deep invaginations filled with digitated epithelial proliferations (Figure 1C). These digitated epithelia contained thick keratogenous zone in the apex. A resected papillary tumor of the nail matrix showed fibroepithelial projections with spindle cell proliferation in the stroma (Figure 1D, E). Immunohistochemical examination revealed that CD10 and CD34 positive cells proliferated in the fibrous stroma (Figure 1F). In addition, S100 and Melan A staining showed scattered melanocytes in the epithelium without evident proliferation (Figure 1G). PCR analysis using human papillomavirus (HPV) consensus primers, L1C1/L1C2 and GP5(+)/GP6(+), was negative (data not shown).1 From these clinicopathological features, we diagnosed as onychomatricoma. Five months followup showed no recurrence (Figure 1H). Onychomatricoma is a benign nail matrix tumor that was first described by Baran and Kint in 1992. Di Chiacchio et al. summarized 30 cases of onychomatricoma and showed the major clinical features including increased nail thickness, splinter hemorrhages, xanthonychia and transverse curvature of the nail. However, longitudinal melanonychia was shown to be less often.2 Pigmented onychomatricoma retains histopathological features of classic onychomatricoma, namely epithelial invagination filled with Vshaped keratogenous zone, abundant fibrillar stroma, and thickened nail plate with cavities occupied by papillary projections of epithelium. Immunohistochemically, CD10 and CD34 are positive for stromal cells.3 These results were consistent with our case. The differential diagnosis of pigmented onychomatricoma includes onychomycosis, traumatic subungual hematoma, Bowen's disease, and subungual melanoma.4 Pigmentation visible through the translucent cuticle like our patient was revealed to be pseudoHutchinson's sign.5 While Hutchinson's sign is common in melanoma, localized hyperkeratosis, dark dots, free edge nail pitting, and hairpinlike vessels are observed more frequently in nail squamous cell carcinoma than in onychomatricoma.6,7 Our case also resembled subungual Bowen's disease which was frequently associated with highrisk HPV infection.1 Since pigmented onychomatricoma often masquerades subungual melanoma and Bowen's disease, we should keep in mind of this rare but specific