October 2003

A 15-year-old male is admitted to the hospital to evaluate and treat an area of erythema, swelling and pain on the anterior aspect of his right thigh. The history of the condition dates back to early childhood when an apparent birthmark was noted in this same area. In fact, the birthmark had become infected on a couple of previous occasions. However, it had always resolved with oral antibiotics. There is no history of injury to the area.

His past medical history is positive for having hernia surgery several years earlier on the right inguinal area. Otherwise, he has been a normal, healthy boy.

Family history and social history are normal. His immunizations are up to date. The patient had varicella as a younger child.

Examination reveals a normal-appearing 15-year-old male with the lesion described above on the right thigh. There is an area of erythema with induration measuring about 7.5 x 8.0 cm, underlying several discrete, fleshy papulovesicular lesions as shown in figures 1 through 3. The patient has no fever and a normal complete blood count. No other lab tests are performed except an MRI of the right lower extremity, as shown in figures 4 through 7.

What’s Your Diagnosis?

1. Infected cystic hygroma
2. Infected lymphangioma circumscriptum
3. Cutaneous herpes simplex
4. Zoster

The answer was ultimately confirmed to be #2, lymphangioma circumscriptum, by pathology when most of the lesion was surgically removed several months later. During hospitalization, the patient was treated with intravenous nafcillin with good results. The patient has remained well since then, with no more infectious complications post-operatively.

As Dr. William L. Weston points out in his Color Textbook of Pediatric Dermatology, the term “lymphangioma” is a misnomer, as this name implies a tumor, when in fact it is a malformation of lymphatic vessels.

Lymphangioma circumscriptum typically consists of an area of skin that has numerous, discrete lesions consisting of vesicles and fleshy papules. Depending on their location, these structures can easily sustain injury, even if unnoticed, that can lead to infection. When this occurs it is probably wise to choose an antibiotic to cover both Staphylococcus aureus and Streptococcus pyogenes. Depending on your community flora, you may have enough community-acquired methicillin-resistant S. aureus (CA-MRSA) to empirically treat for this pending culture results (if obtained). We are now seeing more CA-MRSA than methicillin-sensitive staph in our patients, so we are routinely using clindamycin as empiric therapy for problems like this now. If we suspect bacteremia or sepsis, we use vancomycin pending culture results. Ultimately, these lesions usually undergo surgical removal (figures 8 and 9). For those in difficult locations, sclerotherapy may be attempted. Incomplete removal is common, and about 10% recur.

The appearance of lymphangioma circumscriptum may resemble other vesicle-producing problems, such as cutaneous herpes simplex infections (figure 10) and zoster (figure 11). One key difference is that the appearance of the lymphangioma remains fairly consistent and does not have the erythematous base under the vesicle as herpes simplex virus or zoster lesions. Also, cutaneous herpes and zoster are symptomatic with itching and stinging during the episode before they ultimately resolve.

The term cystic hygroma translates from the Greek word, hygros (moist or wet) into a cystic wet tumor — again, a misnomer. It is not a tumor at all, but rather a cystic (cavernous) lesion, consisting of single or multiple cysts as a result of a different type of lymphatic malformation. They are usually deeper and found in the cervical region, but can occur just about anywhere. These lesions are frequently associated with certain genetic syndromes, such as Turner’s, Noonan’s and certain trisomies, and can be associated with other severe congenital problems that may be lethal to the newborn. These malformations also frequently become infected, probably as a result of inadequate movement of bacteria through the area.

One may actually see features of both lymphangioma circumscriptum with underlying cystic lesions. I don’t know what these are called, but that’s apparently what the patient had presented according to the surgeon that operated on the lesion. One can also see a cystic area on the MRI in figure 4, and on histology of the specimen, there were some muscle fibers associated with the lesion, an occasional pathologic feature of cystic hygromas.

As usual, I recommend any book written by Dr. William L. Weston for additional reading on this or any other pediatric dermatology topic.

By the way, the diagnosis was first confirmed when he had surgery for the hernia, which actually turned out to be part of this malformation.

For more information:

• James H. Brien, DO, Pediatric Infectious Disease, Scott and White’s Children’s Health Center and Associate Professor of Pediatrics, Texas A&M University, College of Medicine, Temple, Texas. E-mail: jhbrien@aol.com.