Extensive burns, either thermal or radiological, can lead to unusually large keloids; these are especially common in firebombing casualties, and were a signature effect of the atomic bombings of Hiroshima and Nagasaki. True incidence and prevalence of keloid in United States is not known. Indeed, there has never been a population study to assess the epidemiology of this disorder. In his 2001 publication, Marneros stated that “reported incidence of keloids in the general population ranges from a high of 16% among the adults in the Democratic Republic of the Congo to a low of 0.09% in England,” quoting from Blooms 1956 publication on heredity of keloids. Clinical observations show that the disorder is more common among sub-Saharan Africans, African Americans and Asians, with unreliable and very wide estimated prevalence rates ranging from 4.5 to 16%. History
Keloids were described by Egyptian surgeons around 1700 BC, recorded in the Smith papyrus, regarding surgical techniques. Baron Jean-Louis Alibert (1768–1837) identified the keloid as an entity in 1806. He called them cancroïde, later changing the name to chéloïde to avoid confusion with cancer. The word is derived from the Ancient Greek χηλή, chele, meaning "crab pincers", and the suffix -oid, meaning "like". The famous American Civil War-era photograph "Whipped Peter" depicts an escaped former slave with extensive keloid scarring as a result of numerous brutal beatings from his former overseer.
As such, they also have a tendency to calcify and are highly vascularized.Meningiomata often are considered benign tumors that can be removed by surgery, but most recurrent meningiomata correspond to histologic benign tumors. The metabolic phenotype of these benign recurrent meningiomata indicated an aggressive metabolism resembling that observed for atypical meningioma. Diagnosis
Meningiomata are visualized readily with contrast CT, MRI with gadolinium, and arteriography, all attributed to the fact that meningiomata are extra-axial and vascularized. CSF protein levels are usually found to be elevated when lumbar puncture is used to obtain spinal fluid. On T1-weighted contrast-enhanced MRI, they may show a typical dural tail sign absent in some rare forms of meningiomas.Although the majority of meningiomata are benign, they may have malignant presentations. Classification of meningiomata are based upon the WHO classification system. Benign (Grade I) – (90%) – meningothelial, fibrous, transitional, psammomatous, angioblastic
Atypical (Grade II) – (7%) – chordoid, clear cell, atypical (includes brain invasion)
Anaplastic/malignant (Grade III) – (2%) – papillary, rhabdoid, anaplastic (most aggressive)In a 2008 review of the latter two categories, atypical and anaplastic-meningioma cases, the mean overall survival for atypical meningiomata was found to be 11.9 years vs. 3.3 years for anaplastic meningiomata. Mean relapse-free survival for atypical meningiomata was 11.5 years vs. 2.7 years for anaplastic meningiomata.Malignant anaplastic meningioma is aggressive. Although anaplastic meningioma has higher chances of distant metastasis than the other two types, the overall incidence of meningioma metastasis is only 0.18%; which is considered rare.