The patient was diagnosed with ACC, according to the clinical, histologic features and course of the disease. About 80% of ACC cases involve the scalp. Less often, the affected areas include the forearms, knees, trunk, legs and face. The condition encom¬passes a heterogeneous group of disorders with or without associated abnormal physical findings, malformation patterns, genetic disease, or a combination of these. Frieden and Sybert have proposed the classification of ACC on the basis of its associated abnormalities and inheritance patterns.
The etiopathogenesis of ACC remains unclear. Several theories have been suggested in an attempt to explain the cause. The vascular theory suggests that there is vascular insufficiency to the skin, perhaps from placental compromise or a thrombo- plastic material. Another accepted theory is that the early rupture of the amniotic membrane was the origin of the process. Such a rupture would permit fluid leakage, leading to the introduction of the fetus into the chorionic cavity. The Chorion will reabsorb this fluid, stimulating the proliferation of mesenchymal bands that envelop and compress the fetal structures, giving rise to malformation of variable severity depending on the degree of em- bryologic development.
Histopathological findings are nonspecific. The epidermis is either missing or consists of a few epidermal cell layers. The underlying dermis is thin and is composed of loosely arranged collagen bundles in which there is some disarray of collagen fibers. The dermis may resemble a scar. Appendages are absent or rudimentary and the subcutis is usually thin. viagra soft
We should consider an association with epidermolysis bullosa type VI. One case of a pretibial aplasia cutis has been described in the literature, but this patient developed bullae and violaceous lichenoid papules and plaques. The patient in this case, however, had no signs of epidermolysis bullosa, and there was no blistering or fragility of the skin. Even the follow up after 2 years did not show any clinical sign of underlying epidermolysis bullosa.