Fukaura Akiko, Numata Takafumi, Chiyotanda Masako, Maeda Tatsuo, Egusa Chizu, Ito Tomonobu, Harada Kazutoshi, Okubo Yukari
Department of Dermatology, Tokyo Medical University.
Department of Pediatrics and Adolescent Medicine, Tokyo Medical University.
Arerugi. 2024;73(2):189-195. doi: 10.15036/arerugi.73.189.
A 2-year-old, male patient presented with an 18-month history of scattered, brown macules and nodules up to 2 cm in size on his trunk and extremities. These macules were accompanied by pruritus and were positive for Darier's sign. A skin biopsy of a brown macule on the left thigh revealed a dense accumulation of CD117-positive, round or oval cells with amphophilic cytoplasm within the upper to middle dermis. The patient was otherwise healthy and had normal laboratory and imaging test results. Sequence analysis of genomic DNA from a skin biopsy demonstrated the presence of an Asp419del mutation in exon 8 of the KIT gene. Based on these findings, maculopapular cutaneous mastocytosis (MPCM) was diagnosed. The patient received H 1-antihistamine. Although the pruritus resolved, the brown macules remained for one year after the initial treatment. To the best of our knowledge, only three cases of cutaneous mastocytosis (CM) with an Asp419del mutation, including the present case, have been reported in the Japanese literature to date; moreover, while the previous two cases were of DCM, the present case was the first instance of MPCM. Normally, the symptoms of childhood-onset MPCM are dormant until puberty. However, a recent study reported that many MPCM patients may experience persistent or exacerbated symptoms. The present study therefore evaluated 53 Japanese cases of childhood onset MPCM with a KIT gene mutation and discussed the patients' clinical outcomes.
一名2岁男性患者，躯干和四肢出现散在的褐色斑疹和结节，大小达2厘米，病程18个月。这些斑疹伴有瘙痒， Darier征阳性。对左大腿上的一个褐色斑疹进行皮肤活检，结果显示在真皮中上段有密集堆积的CD117阳性、圆形或椭圆形细胞，细胞质呈嗜双色性。该患者其他方面健康，实验室检查和影像学检查结果均正常。对皮肤活检的基因组DNA进行序列分析，结果显示KIT基因第8外显子存在Asp419del突变。基于这些发现，诊断为斑丘疹性皮肤肥大细胞增多症（MPCM）。该患者接受了H1抗组胺药治疗。虽然瘙痒症状得到缓解，但初始治疗后褐色斑疹仍持续了一年。据我们所知，迄今为止，日本文献中仅报道了3例包括本病例在内的具有Asp419del突变的皮肤肥大细胞增多症（CM）；此外，前两例为弥漫性皮肤肥大细胞增多症（DCM），而本病例是MPCM的首例。通常，儿童期发病的MPCM症状在青春期前处于潜伏状态。然而，最近一项研究报告称，许多MPCM患者可能会出现持续或加重的症状。因此，本研究评估了53例日本儿童期发病的具有KIT基因突变的MPCM病例，并讨论了患者的临床结局。
