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 lung nodules. Simply, a benign lung nodule is not cancerous. A benign nodule or mass will not spread to other areas of the body. However, the presence of benign nodulesâespecially if they are largeâcan cause health problems. Even benign lung nodules may have to be surgically treated and removed. The most common types of benign lung nodules include: Granulomas: Inflamed or infected tissue that has congealed into a globular or ball-like shape.