Wallworth Taylor M, Husson Christopher, Roberie Dustin, Rooks Veronica
School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
Department of Radiology, Tripler Army Medical Center, Honolulu, HI, USA.
Radiol Case Rep. 2024 Jan 17;19(4):1452-1456. doi: 10.1016/j.radcr.2024.01.019. eCollection 2024 Apr.
Pilomatricomas (PM) are benign neoplasms that arise from hair follicle matrix cells. They are one of the most frequently excised pediatric skin masses. A typical clinical presentation is a slow growing, painless, firm, superficial mass in the head and neck of a child. We present a rare presentation of PM. A preschool aged girl presented with an enlarging scalp mass following a history of minor blunt trauma to the area. Two months prior, the child sustained a ground level fall and subsequently developed a painless "bump" at the site of injury on the scalp. The ``bump" was initially the size of a "mosquito bite" and enlarged to the size of a "ping pong ball". Given the rapid progression and history of trauma, there was a broad differential diagnosis. An extensive workup including sonography, computed tomography, MRI, and biopsy were performed. The final pathologic diagnosis was confirmed as pilomatricoma. An atypical presentation of PM in a child can mimic a wide variety of pathology. Our case demonstrates unusual features of rapid enlargement and preceding trauma. With the widespread use of sonography for evaluation of superficial lesions, the radiologist may be the first to suspect the diagnosis of PM. Knowledge of the typical imaging findings in PM can be valuable, especially in more unusual cases.
毛发上皮瘤（PM）是起源于毛囊基质细胞的良性肿瘤。它们是儿科最常切除的皮肤肿物之一。典型的临床表现是儿童头颈部缓慢生长、无痛、质地硬的浅表肿物。我们报告一例罕见的毛发上皮瘤表现。一名学龄前女童，在该区域有轻微钝性外伤史后，头皮肿物逐渐增大。两个月前，该儿童平地摔倒，随后在头皮受伤部位出现一个无痛的“肿块”。这个“肿块”最初如“蚊虫叮咬”大小，后来增大到“乒乓球”大小。鉴于其快速进展和外伤史，鉴别诊断范围很广。进行了包括超声、计算机断层扫描、磁共振成像和活检在内的全面检查。最终病理诊断确诊为毛发上皮瘤。儿童毛发上皮瘤的非典型表现可模仿多种病理情况。我们的病例显示出快速增大和外伤史等不寻常特征。随着超声广泛用于评估浅表病变，放射科医生可能是第一个怀疑毛发上皮瘤诊断的人。了解毛发上皮瘤的典型影像学表现可能很有价值，尤其是在更不寻常的病例中。
