Isolated Aplasia Cutis Congenita on Left Foot in Chinese Neonate

Aplasia Cutis Congenita (ACC) is a rare condition characterized by absence of skin layers, usually on the scalp, but can also affect the foot. ACC can occur as an isolated condition or in the presence of the other congenital anomalies. Here we describe a case of a 1-day-old baby boy with an isolated ACC of the left foot, with no family or siblings positive disease history. The patient was managed by both conservatively and surgically until the defect has formed scar tissue 5 months later.


Introduction
Aplasia Cutis Congenita (ACC) is a rare congenital abnormality involving variant layers of the skin, mostly as a solitary lesion involving the midline over the skull vertex [1].May occur in other sites as well as the chest, abdomen, or limbs, less commonly, underlying periosteum and bone [2] [3].It was first described in 1767 by Cordon, around 500 similar cases have been reported so far [4].Frieden classified the different anomalies into 9 groups based on the number and the presence or absence of other anomalies [5] (Table 1).The lesions in those cases are quite variable, ranging from only local absence of skin to a complete absence of epidermis, subcutaneous tissue, bone, or in some cases the dura [6] [7].The incidence of ACC is estimated as 1 per 10,000 live births [1].This occurs frequently in females.The etiology remains unclear so far; however, both genetic and environmental causes have been implicated, including vascular blood supply, a sudden arrest of midline embryological development, and failure in neural tube closure, and syphilis has at one time contributed as the cause [1] [8].Rupture of amniotic membrane in an early time, forming amniotic bands, may also be from the cause [5].A number of teratogenic drugs such as Methimazole, a Thiomidazole derivative used as an antithyroid agent, have shown to be involved [9] [10].There are similar cases, classified as being of an autosomal-dominant inheritance [11].Establishing a diagnosis is usually based on the findings of the clinical examination, typically presenting as a hairless, smooth skin defect covered up by atrophic tissue or a dark colored eschar.Superficial defects presenting as an ulcer are usually treated conservatively.Extensive or deep defects may require reconstruction of the scalp area or the use of bone transplants.

Case Summary
A 4200-g boy was delivered by a 27-year-old mother, gravida 1 para 0, by LUCS at 39 weeks of gestation due to oligohydramnios in changan district hospital Xi'an China, at the age of 1 day, the neonate was admitted to NICU of Xi'an Jiaotong first affiliated hospital because of the morphological abnormalities and abnormal skin over the left foot and leg since birth.The medical history of neonate was unremarkable, his mother denied any history of illness during her pregnancy except she had high blood pressure (140/95) before the 1 day of delivery, infection or drug intake including Methimazole or NSAIDS.The neonate didn't suffer any other feeding difficulties or abnormalities.Upon the local ex-amination the defect was solitary, localized with an approximately 5 × 5 cm in size and irregular in shape.The patient was treated with conservative methods in the beginning like; local therapy and non-invasive debridement of the lesion, which included application of topical antibiotic ointment and gentle water cleansing.Although the conservative methods were showing gradually improvement but surgical treatment were also under consideration for further improvement due to its large lesion, as it can be prevented the fatal complications and the cosmetic results are usually better.1) where skin is deficient and covered by thin red membrane and restricted movement.Other system revealed normal.

On Examination
Figure 2 shows after the age of six weeks, ongoing healing with secondary intention, but at the age of 16 to 18 weeks wound healed with a small crust (Figure 3) and finally at the age of 5 month showing the complete secondary healing of  the aplasia cutis Congenita defect (Figure 4). Figure 5 shows the images of "Skin Biopsy": From ulcerated lesion.

Investigation
Table 2 showed blood investigation parameters of the patient in the given number.

Discussion
ACC occurs as a solitary defect; it can happen alone or in the presence of syndromic congenital anomalies.The involvement of the scalp area may lead to the understanding of the etiology.Upon our review to the literature available, Cases were often characterized by an entire absence of skin.Histologically, we found that most of the lacking tissues belonged to epithelial ectoderm.The condition could be associated with chromosomal defects [12].Some researches show the association with gestational conditions such as an intrauterine vascular ischemia, amniotic adherences, and viral infections [13] [14].A rise of alpha-fetoprotein levels and a distinct amniotic fluid acetylcholinesterase band were found in recent article as markers for ACC [15].Also, a number of drugs have been linked to ACC.For example, the use of cocaine during pregnancy can lead to vasoconstriction of the placenta or disruption of the fetus vascularity, causing the cranial defects and anomalies of the central nervous system (CNS) [16].Methimazole, a drug used for the treatment of hyperthyroidism, may show some skin affection.
Benzodiazepines use is also linked with ACC as described by Martínez-Lage et al. [7].Surgical treatment requires careful preoperative planning [17].Minimal superficial lesions are treated conservatively to heal gradually by epithelialization and result with a hypertrophic or atrophic scar.Tissue expander insertion may be necessary in extensive lesions reaching the scalp, whereas the one deep enough to reach the brain, bone, and meningeal transplants may be indicated [8] [18] [19] [20].Deep defects overlying the sagittal sinus are indicators for urgent surgical intervention to prevent potentially lethal infections or hemorrhage [7] [21].Grafting [22] and temporary use of biological dressings [23] and silver sulfadiazine dressings while waiting for the processes of skin and bony in growth [3] have been published with variable degree of success.A broad approach of therapeutic approaches are still being used for ACC.Due to the characteristics of this study we were still unable to determine that which treatment is best for ACC.On the other hand surgical management is generally preferred, especially for the large lesions, as it can prevent fatal complications and the cosmetic results are better.

Conclusion
We believe that ACC is a disease that carries the risk of potentially fatal complications, but that these can be prevented with an appropriate treatment.Aplasia Cutis Congenita is a rare congenital disorder characterized by absence of skin, most frequently overlying the scalp.ACC can be associated with many anomalies.We report a case of a newborn with isolated leg and foot ACC, which was treated conservatively.Although neither of the parents had ACC.

Figure 1 .
Figure 1.The newborn presented with the skin defect of the left foot on day one.

Figure 2 .
Figure 2. Six week postnatally, showed ongoing healing by secondary intention.

Figure 3 .
Figure 3.At the age of 16 -18 weeks the wound healed with a small crust remaining.

Figure 4 .
Figure 4.At the 5 th months, showing the complete secondary healing of the aplasia cutis congenita defect.

Table 1 .
Classification for ACC.

Table 2 .
Blood investigation parameters of the patient.