Benign Skin Lesions

Abstract

Virtually every child has a number of benign growths on the skin. Parents of children who ask their pediatrician to look at a growth are usually concerned that the lesion may be cancerous or precancerous. Many papules and nodules that arise in children have very characteristic clinical features that allow a diagnosis to be made without the aid of histological or radiographic evaluation. However, some lesions may be very non-specific in appearance and require a biopsy to make a diagnosis. In some situations, obtaining an imaging study is desirable before a biopsy is performed. For example, lesions along the midline of the face, scalp, and back frequently have connections to the brain or spinal cord, and care must be taken to avoid biopsy of any midline lesion until such a communication is ruled out, usually by CT or MRI.

Appendices

Summary Points

Most skin lesions in infants and children are benign.

Approximately 75% of warts will spontaneously resolve within 3 years.

Evaluate any patient with a neurofibroma for skin findings of NF type I.

Most hemangiomas can simply be observed but parental reassurance is necessary.

Lesions that pose significant cosmetic concerns such as those involving the face may require early medical intervention.

Nevi that have an atypical appearance or have changed abruptly require complete excision.

Prophylactic excision of nevus sebaceus is no longer recommended.

Editor’s Comment

The back is a common place for subcutaneous lesions such as lipomas, lymphangiomas, and fibromas to arise in infants and children. Typically off the midline and below the level of the scapula, these tend to be large, flat lesions with indistinct borders and a high risk of recurrence after surgical excision. Ultrasound or MRI can be useful to determine the true extent and to help with surgical planning. It is also helpful to delay excision until the child is more than a year of age when the dissection planes within the fat are somewhat easier to delineate. These will sometimes turn out to be due to nodular fasciitis, an inflammatory lesion that causes the fascia of the paraspinous muscles to thicken and fibrose. Excision usually leaves the muscle without investing fascia, which is functionally not an issue. In the end, these lesions are all benign and mostly of cosmetic concern, therefore the least invasive operation with the best cosmetic result should be the goal.

Other uncommon but challenging skin lesions occasionally seen in a typical pediatric surgical outpatient practice include tick bites and myiasis. Tick bites create a lot of anxiety in some parts of the country because of concerns about Lyme disease, but surgeons are sometimes asked to assess a child who has had a tick removed in such a way that the mouth parts have been left embedded in the skin. This can cause an intense foreign body reaction or even a local vasculitis. If the lesion persists after a 2-week period of observation, surgical excision is sometimes necessary. Cutaneous myiasis is due to growth within the skin of the larva of the botfly, which is indigenous to parts of Central and South America. The dermal lesion is typically red, raised, and itchy with a small central hole (breathing pore) through which a serosanguinous discharge (feces) is intermittently seen. Patients will sometimes also describe the feeling that something is wriggling within the lesion. The larva will eventually come out on its own and the course is benign, but few patients or parents in the US will tolerate such “therapy.” Home remedies abound, including the application of petrolatum to suffocate the larva, but surgical extraction under general anesthesia is often the best option.

For dermoid cysts that are located within a slight concavity of the skull, it is important to remove the underlying periosteum to prevent recurrence. It is tempting to attempt retrieval of a foreign body in the foot in the office or Emergency Department, but this is often a frustrating exercise that can push the foreign body deeper. The foot has many intersecting subcutaneous fibrous septae that are difficult to navigate, can allow the foreign body to hide, and can make the practitioner appear to be incompetent in the eyes of the parents. Unless the foreign body is directly visible, it is always best to perform the extraction in the operating room, under general anesthesia, and, if the foreign body is radiopaque, under fluoroscopic or ultrasound guidance. When dealing with any foreign body extraction, it is important to warn the parents about the possibility of a retained foreign body and carefully document that the foreign body has been extracted, usually with a follow-up radiograph. Always insist on a follow-up visit so that you can be sure that the wound has healed well with no evidence of infection or foreign body. These situations are often highly charged, both emotionally and legally.

Diagnostic Studies

CT/MRI lesions arising near the medial canthus of the eye, along the nose, or along suture lines of the skull to rule out intracranial extension

Ultrasound or MRI may be useful to characterize lesions and evaluate extent/depth of the lesion

MRI of brain/spine to rule out CNS involvement pre operatively in giant congenital melanocytic nevi involving posterior midline

Ultrasound or plain radiograph to document foreign body

Parental Preparation

• Reassurance is needed for lesions not excised on first visit.

• Discussion of risks: wound infection, seroma, hematoma, scarring.

Technical Points

The entire lining of an epidermoid cyst must be removed to prevent recurrence.

Excise worrisome lesions initially with a narrow margin.