Question
Clinical Presentation
A 53-year-old man presented with a 2-year history of an asymptomatic fingernail dystrophy. There was no history of trauma. Upon clinical examination, the left first fingernail had a partial longitudinal, thickened, yellowish plate (Fig. 1).
Fig. 1.
Clinical presentation. Thickened, yellowish plate.
Dermoscopic Appearance
Dermoscopic examination revealed a longitudinal band of xanthonychia with splinter hemorrhages involving the proximal and distal nail plate, longitudinal parallel white lines, and thickening of the free edge along with multiple cavities at the distal nail plate margin (Fig. 2).
Fig. 2.
a Dermoscopy showing proximal and distal splinter hemorrhages within the band of xanthonychia, along with longitudinal parallel white lines. b Thickened free edge with multiple cavities.
What is your diagnosis?
Answer
Onychomatricoma
Histologic Diagnosis. Subungual exploration revealed a villous tumor in the nail matrix (Fig. 3). A shave biopsy showed a tumor composed of epithelial cell strands that vertically penetrated into a fibrotic dermis and appeared to be lined with optical cavities (Fig. 4). This confirmed the diagnosis of an onychomatricoma.
Fig. 3.
Villous tumor originating from the nail matrix.
Fig. 4.
Histopathological findings of onychomatricoma: strands of epithelial cells originating from the nail matrix that penetrate into the fibrotic stroma, the strands appear to be lined with optically clear cavities (hematoxylin-eosin stain; original magnification, ×5).
Key Message. The presence of longitudinal thickening and xanthonychia should always raise suspicion of an onychomatricoma. Splinter hemorrhages and holes in the distal margin of the nail plate are other common clinical features. Dermoscopy provides criteria that are less subject to misinterpretation. Nail clipping is a simple, noninvasive diagnostic tool in case of doubt. Dermatologists should be familiar with this benign tumor to avoid delaying diagnosis [1,2].
Statement of Ethics
Patient's identity was protected in the manuscript and written permission for photograph use was signed by the patient.
Disclosure Statement
The authors have no conflicts of interest to disclose.
References
- 1.Di Chiacchio N, Tavares GT, Tosti A, Di Chiacchio N, Di Santis E, Alvarenga L, et al. Onychomatricoma: epidemiological and clinical findings in a large series of 30 cases. Br J Dermatol. 2015;173:1305–1307. doi: 10.1111/bjd.13900. [DOI] [PubMed] [Google Scholar]
- 2.Lesort C, Debarbieux S, Duru G, Dalle S, Poulhalon N, Thomas L. Dermoscopic features of onychomatricoma: a study of 34 cases. Dermatology. 2015;231:177–183. doi: 10.1159/000431315. [DOI] [PubMed] [Google Scholar]