Acquired Localized Longitudinal Pachyonychia and Onychomatrical Tumors: A Comparative Study of Onychomatricomas and Onychocytic Matricomas

This study compared the clinical and histopathologic characteristics of onychocytic matricomas (OCMs) and onychomatricomas (OMs) through 4 cases of OCMs and 5 cases of OMs. Both types of tumors exhibited a thickened nail plate with a longitudinal band pattern, but OCMs showed a V-shaped keratogenous epithelial tumor with a papillomatous growth pattern, while OMs displayed a panonychoma fibropapilliferum pattern. The study highlighted the importance of nail clipping in diagnosing onychomatrical tumors, suggesting that larger cavities in the nail plate (over 0.15 mm) could indicate a benign growth, potentially avoiding unnecessary excisional procedures. Conversely, smaller cavities (under 0.10 mm) should lead to a biopsy to exclude malignancy.