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).
Lichenoid keratosis is an uncommon, benign skin condition, which typically consists of a single lesion, usually on the upper torso and the distal upper extremeties, but in some cases may appear on the head or neck.Lichenoid keratosis is divided into subtypes which are predicated on the appearance of the lesion.ichenoid keratosis is an uncommon, benign skin condition, which typically consists of a single lesion, usually on the upper torso and the distal upper extremeties, but in some cases may appear on the head or neck. Lichenoid keratosis is divided into subtypes which are predicated on the appearance of the lesion.