Section 27. Miscellaneous Anomalies

Among the many hazards of intrauterine development and sojourn is failure at times to achieve complete congenital integrity of the integument. It sometimes happens that a child is born with a superficial erosion, as in Fig. 27-1, or an ulcer, as in Figs. 27-2 and 27-3. The vertex of the scalp is a common place for the phenomenon to occur; the hands, face, and points over bony prominences are also susceptible. Aplasia cutis congenita is frequently a benign event of only cosmetic importance, and in most cases the etiology is not established. However, epidermolysis bullosa, placental infarction, teratogens, and some chromosome deletions and trisomies are occasionally implicated as causes. A lesion may be directly adjacent to an epidermal nevus or nevus sebaceus, or it may overlie a defect in the bone. More significant underlying anomalies are meningomyeloceles, spinal dysraphisms, and various cerebral malformations. Hemorrhage and secondary infection may occur, requiring emergency treatment. The combination of aplasia cutis congenita and distal limb reduction is an additional inherited disorder.

A lesion may be directly adjacent to an epidermal nevus or nevus sebaceus, or it may overlie a defect in the bone (Fig. 27-3). More significant underlying anomalies are meningomyeloceles, spinal dysraphisms, and various cerebral malformations. Hemorrhage and secondary infection may occur, requiring emergency treatment. The combination of aplasia cutis congenita and distal limb reduction is an additional inherited disorder.

This radiograph represents a case of aplasia cutis congenita associated with a significant underlying skull defect. Smaller defects of the skull may occur with smaller cutaneous lesions. These smaller bony defects usually heal in a few months. The larger lesions may require neurosurgical repair.

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 form fruste of a neural tube defect. This figure shows a membranous variety of aplasia cutis congenita.

The presence of a “hair collar” around a scalp nodule or lesion of aplasia cutis congenita can sometimes be a marker for cranial dysraphism, such as encephalocele or heterotopic brain tissue. 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.