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.