Infectious Diseases in Children, 8/2008: A 3-year-old boy presented for evaluation of a painless lesion on his right palm at the hypothenar eminence.
The lesion was first noticed a few months earlier as a small papule and has been growing fairly rapidly. Interestingly, this is occurring in the same location that he previously injured two months earlier with a minor burn that required no evaluation or therapy. However, the patient’s history is complicated by a previous diagnosis of leukemia and he is still receiving chemotherapy with 6-mercaptopurine and methotrexate. His past medical history is otherwise unremarkable.
On examination, a large, well-circumscribed fleshy lesion with some dark, pinpoint spots under a somewhat rough surface and a small area of desquamation at its edge was noted on the hypothenar eminence of his right hand (see figures 1 and 2). The rest of his examination was unremarkable.
What’s your diagnosis?
Answer
Verrucua vulgaris, the common cutaneous wart, which IS a benign soft tissue tumor. The clues include the well-circumscribed lesion with the characteristic “black dots” that are seen on closer examination, which represent small, thrombosed blood vessels, as well as the history of a prior injury to the same area.
I’m sure you all have taken care of children with warts from time to time. However, the fact that this patient has leukemia warrants special mention. Although the immunity to the viruses that cause the various types of warts is not completely understood, it has been known since the advent of chemotherapy for cancer and recognition of other immunodeficiency states decades ago, that common warts in these patients behaved uncommonly. Children with an immunodeficiency, particularly those with cell-mediated deficiencies, have much more difficulty with common cutaneous warts being resistant to therapy and being larger in size and numbers. When I first saw the lesion on the patient presented above, I was not sure of the diagnosis. It took a dermatologist to enlighten me by looking close for some of the features noted above, and couple that with the fact that the child was on chemotherapy.
When I think of the common cutaneous wart, I think of a lesion like a wart on the knee of my neighbor’s son, just after it had been subjected to cryotherapy, therefore the inflamed look. It has the more characteristic rough, keratotic surface through which you can see a few of the black dots (thrombosed capillaries) mentioned above. Some will respond well with 40% salicylic acid, but this may take several weeks of daily applications. The vast majority will respond to one or two applications of simple cryotherapy or laser therapy. The majority will resolve over a few years of time without any therapy. Some special cases may require a more “toxic” product, such as podophyllin, which is a plant resin that inhibits cell division.
Another option that the dermatologist may use is topical cantharidin, which is a potent vesicant secreted by the blister beetle. This can be carefully applied to the lesion with a small stick or applicator so as not to damage the surrounding skin. This was the treatment used in the case presented. After a series of three applications over a three-month period, the lesion completely sloughed off. Sometimes success in these cases coincides with stopping the chemotherapy long enough for the immune system to recover.
By now, everyone probably knows that of the many different types of human papillomaviruses (>100), that may cause various types of mucocutaneous warts, that certain types are associated with development of genital carcinoma (types 16, 18, 31, 33, 35, 39, 45 and 51). The Merck vaccine, Gardasil, immunizes against types 16 and 18, which make up about 70% of the types that cause cervical cancer, as well as types 6 and 11, which cause about 90% of genital warts, and has been recommended for female patients between the ages of 11 and 26 as a three-dose series. These and other types become even more problematic in immunodeficient cancer patients in that there is even more risk for malignant transformation.
Another HPV-related cancer is verrucous carcinoma, also known as the Ackerman tumor after Lauren V. Ackerman, MD; a leader in surgical pathology during the 20th century, and who described this condition in 1948. This is a variant of a squamous cell carcinoma that occurs mostly in the oral mucosa in areas subjected to chronic inflammation, such as chewing tobacco, mostly in middle-aged to elderly white men (glad I gave up my “Red Man” a long time ago). There appears to be a clear association with HPV and verrucous carcinoma, particularly HPV type 16. You will not likely see this in children, but I thought it was noteworthy in the context of discussing HPV-related cancers. For those interested in more information on the subject of HPV and cancer, the library and internet are loaded with information on HPV and warts.
Molluscum contagiosum is another common childhood cutaneous infection caused by a virus, only this one is a poxvirus (molluscipoxvirus types 1 – 4). The virus causes epidermal cell proliferation, giving it the characteristic fleshy, dome-shaped lesion with a white core that contains the virus. The lesion will become umbilicated as it gets larger. These lesions are easily spread from person to person, and 10 to 15% of children will have these sometime during childhood, especially between 1 and 10 years of age. When they are seen in the anogenital area (figure 5, courtesy of Jim Bass), one must consider the possibility of sexual abuse, although knowing the hand habits of children, it would be easy for these lesions to occur in these places as well through “natural” circumstances. Just need to think about it. Treatment of these lesions, which have no cancer risk, are similar to the treatment of warts noted above, plus one can simply curette them off if the patient will tolerate it. Like warts, these lesions can become very numerous and more difficult to treat in the immunosuppressed patient.
