What condition is characterized by thickened epidermal areas and may develop into a nodular mass in dogs?

The condition characterized by thickened epidermal areas that may develop into a nodular mass in dogs is Bowen's disease. This is an intra-epithelial neoplasm, primarily affecting keratinocytes and is often a sign of chronic skin damage or irritation, commonly linked to viral infections or repeated trauma. In dogs, Bowen's disease can result in hyperkeratotic plaques that are usually slow to progress but have the potential to develop into more complex lesions or nodules over time.

Understanding this condition is essential as it forms part of a spectrum of skin lesions that may occur in canines, recognized for their slow progression and limited invasiveness compared to other forms of skin tumors. In contrast, the other options listed typically exhibit more aggressive behavior or different patterns of invasion, making Bowen's disease a unique entity among them.