Dermoscopy Dots and Globules
Dots are formed when pigment or cells occur in clumps. Nevi change with age. Junction nevi are found in childhood and early adolescence. They consist of uniform groups of benign pigment cells. These tiny groups of cells are located in the lower epidermis and upper dermis. These nests of cells appear as small uniform dark dots when viewed from above. Junction nevi evolve into compound nevi as cells clump together and drop into the dermis. The nests are usually larger but still remain uniform in size. Larger nests or groups of pigmented cells in the dermis form large dots called globules.
Both dots and globules may occur in benign and malignant melanocytic lesions. In benign lesions they are regular in size and shape and evenly distributed. In melanomas they tend to vary in size and shape and are frequently found in the periphery of lesions.
Melanin pigment in the upper epidermis and stratum corneum is usually black. Pigment found in the upper epidermis is suspicious for melanoma. Melanin appears brown when it accumulates at the dermoepidermal junction. Gray-blue granules (peppering) are caused by tiny melanin structures in the papillary dermis. Gray-blue or blue granules are due to loose melanin and fine melanin particles or melanin dust in melanophages or free in the deep papillary or reticular dermis. Melanin found deep in the dermis in blue nevi and melanoma appears blue.