Monodactylous Longitudinal Melanonychia: A Sign of Bowen's Disease in Skin of Color.

Introduction: Monodactylous longitudinal melanonychia (LM) may represent both benign and malignant dermatologic disorders. However, squamous cell carcinoma in situ (SCCis) is not commonly considered in this setting.

Case Presentation: In this report, we present 2 cases of SCCis of the nail matrix in patients with skin of color who presented with monodactylous LM involving the lateral aspect of the nail.