Case 12 Male, 27 years. Brown macule with central black papule, lumbar skinShow diagnosis & comments
Minor junctional naevus NOS component and more extensive but supreficially located 'deep penetrating' naevus component in the superficial dermis.
The term 'deep penetrating naevus' refers to the fact that most of these lesions penetrate the dermis deeply, usually around a hair follicle and resulting in a wedge shape. However, some examples are limited to the superficial part of the dermis. The most characteristic features are the relative large and lightly pigmented cell type, the formation of small cell groups at all levels, the production of pigment at all levels (no so-called 'maturation') and the presence of a small number of mitotic figures, which again may occur at all levels.