Acral Subcorneal Hematoma Mimicking Melanoma: Dermoscopic Features and Exploratory Digital Color Analysis

Acral pigmented lesions pose a diagnostic challenge due to the overlap between benign entities, such as subcorneal hematoma, and acral melanoma. Dermoscopy is a key noninvasive tool that aids in differentiation by revealing subsurface structures not visible to the naked eye. We report the case of a 54-year-old man presenting with an asymptomatic acral pigmented macule on the volar aspect of the finger. Clinically, the lesion appeared dark reddish-brown, raising concern for a melanocytic process; however, dermoscopic evaluation revealed a homogeneous, predominantly red, structureless pattern without melanocytic features. Based on these findings, a subcorneal hematoma was diagnosed, and a conservative approach was adopted. To further explore the discrepancy between clinical and dermoscopic appearance, exploratory digital image analysis was performed. RGB histogram analysis demonstrated a predominance of the red channel in both clinical and dermoscopic images, with a greater relative contribution under dermoscopy. Additional evaluation using the CIELAB color space confirmed the presence of red chromatic components and revealed a shift in relative chromatic contrast between the lesion and surrounding skin. These findings are exploratory and serve to support, rather than establish, the observed optical phenomenon. This case suggests that dermoscopy enhances the visibility and relative contrast of pre-existing chromatic components through optical modulation, rather than generating new information. The observed clinical-dermoscopic discrepancy highlights the role of optical factors and contrast modulation in color perception and underscores the value of dermoscopy in increasing diagnostic confidence and potentially avoiding unnecessary biopsy in appropriate clinical contexts.