Clear cell acanthoma (also known as Acanthome cellules claires of Degos and Civatte, Degos acanthoma, and Pale cell acanthoma) is a benign clinical and histological lesion initially described as neoplastic, which some authors now regard as a reactive dermatosis. It usually presents as a moist solitary firm, brown-red, well-circumscribed, 5 mm to 2 cm nodule or plaque on the lower extremities of middle-aged to elderly individuals. The lesion has a crusted, scaly peripheral collarette and vascular puncta on the surface. It is characterized by slow growth, and may persist for years. The clinical differential diagnosis includes: dermatofibroma, inflamed seborrheic keratosis, pyogenic granuloma, basal-cell carcinoma, squamous cell carcinoma, verruca vulgaris, psoriatic plaque, and melanoma. Histology
Clear cell acanthoma is characterized by a sharply demarcated psoriasiform epidermal hyperplasia composed of a proliferation of slightly enlarged keratinocytes, and basal cells with pale-staining glycogen-rich cytoplasm, mild spongiosis and scattered neutrophils, which may form small intraepidermal microabscesses. Oedematous dermal papillae are typically seen with increased vascularity and a mixed inflammatory infiltrate including lymphocytes, plasma cells and neutrophils. Treatment
Simple surgical excision is curative. : 636 : 777

See also
Epidermis
List of cutaneous conditions
List of cutaneous neoplasms associated with systemic syndromes


== References ==
Normally resulting lactate concentrations are in the range indicated below:
Lactic acidosis is classically defined as an elevated lactate together with pH < 7.35 and bicarbonate below 20 mmol/L, but this is not required as lactic acidosis may exist together with other acid-base abnormalities that may affect these two parameters. Treatment
If elevated lactate is present in acute illness, supporting the oxygen supply and blood flow are key initial steps. Some vasopressors (drugs that augment the blood pressure) are less effective when lactate levels are high, and some agents that stimulate the beta-2 adrenergic receptor can elevate the lactate further.Direct removal of lactate from the body (e.g. with hemofiltration or dialysis) is difficult, with limited evidence for benefit; it may not be possible to keep up with the lactate production.Limited evidence supports the use of sodium bicarbonate solutions to improve the pH (which is associated with increased carbon dioxide generation and may reduce the calcium levels).Lactic acidosis caused by inherited mitochondrial disorders (type B3) may be treated with a ketogenic diet and possibly with dichloroacetate (DCA), although this may be complicated by peripheral neuropathy and has a weak evidence base. Prognosis
Mild and transient elevations in lactate have limited impact on mortality, whereas sustained and severe lactate elevations are associated with a high mortality.The mortality of lactic acidosis in people taking metformin was previously reported to be 50%, but in more recent reports this was closer to 25%. Other animals
Reptiles
Reptiles, which rely primarily on anaerobic energy metabolism (glycolysis) for intense movements, can be particularly susceptible to lactic acidosis.