Section 30: Miscellaneous Anomalies

Aplasia cutis congenita This not uncommon disorder is characterized by congenital localized areas of missing skin. These may present as ulcers, or may have already healed by the time of birth. The most common location is the vertex of the scalp. Figure 30-1 depicts a child born with superficial erosion.

Shown in Fig. 30-2 is a child with a significant ulcer as a presentation of aplasia cutis congenita. Lesions of this type inevitably heal with scarring, and with an area of alopecia. Most infants have a single lesion, although multiple lesions may occur.

Aplasia cutis congenita Although the occurrence of this condition is usually an isolated event, it may be seen in a number of syndromes. In Adams-Oliver syndrome, distal limb reduction abnormalities are found in association with solitary midline scalp defects. SCALP syndrome is the constellation of nevus Sebaceus, Central nervous system malformations, Aplasia cutis congenita, Limbal dermoid, and Pigmented nevus.

This radiograph represents a case of aplasia cutis congenita associated with a significant underlying skull defect. When this occurs, there is a higher risk of infection and bleeding. These smaller bony defects usually heal in a few months. The larger lesions may require neurosurgical repair.

Aplasia cutis congenita Sometimes a thicker, darker growth of hair may be seen around the lesion of aplasia cutis congenita on the scalp. The “hair collar sign” may be a marker for cranial dysraphism such as encephalocele, agenesis of the corpus callosum, and heterotopic brain tissue. This may be a forme fruste of a neural tube defect.

Figures 30-5 and 30-6 show a membranous variety of aplasia cutis congenita. Although lesions of this type may be mistaken for bullae, the location and hair collar signify that this is a defect of skin closure covered by a thin membrane.

Aplasia cutis congenita Seen in Fig. 30-7 is another infant with a “hair collar” sign. In this patient, there is aplasia cutis congenita with both a vascular stain and a whorl of hair. This combination of cutaneous findings might raise particular concern about an underlying abnormality and should prompt appropriate imaging of the brain.

This is an example of a lesion of aplasia cutis congenita that has healed into a scar. This process may occur in utero or shortly after birth. Figure 30-8...