Coal forms from the accumulation of plant debris, usually in a swamp environment. When plant debris dies and falls into the swamp the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay.
Porokeratosis is generally considered to be a benign condition though malignant transformation has been seen in all but the punctate variety, necessitating regular followup of patients with porokeratosis (Maubec et al., 2005; Sasson & Krain, 1996).
Benign atypical junctional melanocytic hyperplasia is characterized by a proliferation of these large cells along the dermoepidermal junction. They are dispersed at uneven intervals and are too few in number to be considered compound nevi.wenty-five of the 400 cases reviewed (6.2%) exhibited benign atypical junctional melanocytic hyperplasia. Patient ages ranged from 18 to 64 years (mean, 35 years). The male to female ratio was 1:1. Lesions were predominantly located on the face (40%) and back (32%).