Giant Onychomatricoma of the Great Toenail: Case Report and Review Focusing on Less Common Variants

Abstract

Onychomatricoma is a rare benign fibroepithelial filamentous tumor originating from the nail matrix. It typically presents with the clinical tetrad of xanthonychia, pachyonychia, proximal splinter hemorrhages and increased transverse overcurvature of the nail plate. The giant variant can easily confuse the clinician due to its extensive nail dystrophy that can mask the characteristic features of this tumor. Benign (fibrokeratoma, ungual fibroma, onycholytic matricoma) and malignant entities (Bowen's disease, squamous cell carcinoma, onycholytic carcinoma) are mimics of the disease. Nail surgery can facilitate the diagnosis, which should always be confirmed by histology, as rare variants do exist.

Keywords: Giant; Nail tumor; Onychomatricoma; Uncommon type.

Fig. 1

Extensive nail dystrophy with marked pachyonychia, nail plate fracture and cavities accompanied by paronychia (the red color is due to chronic application of iodine-based antiseptic solution).

Fig. 2

An overview of the tumor, together with the overlying keratinizing, nail-type squamous epithelium (hematoxylin and eosin staining, ×10).

Fig. 3

Preoperative image. Nail plate thickening is now more prominent.

Fig. 4

Intraoperative image showing the tumor's finger-like projections.

Fig. 5

Multiple woodworm cavities occupying the nail plate.