CASE

A 24-year-old white female presented to the dermatology clinic with a 2-year history of growths on the soles of her feet. The growths were not painful when walking, but felt like “a bunch of stones in her shoes.” The patient tried several OTC callous-removal products, but they were ineffective. The growths appeared to be more prominent in the weight-bearing areas of her feet.

The patient had undergone a kidney transplant 3 years previously. Her medications included azathioprine (Imuran), 150 mg daily; prednisone, 10 mg every other day; amiloride/ hydrochlorothiazide (Moduretic), 5 mg/50 mg daily; pantoprazole (Protonix), 40 mg daily; and risedronate (Actonel), 35 mg weekly. She was otherwise healthy. She denied using tobacco, alcohol, or illicit drugs.

Physical examination revealed multiple hyperkeratotic papules and plaques on the soles of the feet (see Figure 1). No associated erythema or edema was found. Some scaling was seen. Closer examination revealed that the skin lines were interrupted. A scraping with a #15 blade was obtained. Dark spots, or seeds, were visible on the scraped area. Examination findings of the patient's remaining skin were unremarkable.

WHAT IS YOUR DIAGNOSIS?

  • Verruca plantaris
  • Piezogenic pedal papules
  • Squamous cell carcinoma
  • Corns

DISCUSSION

The patient has verruca plantaris, a condition commonly known as plantar warts. This condition is caused by the human papillomavirus (HPV). The seeds are thrombosed capillaries, which are diagnostic for warts.

The diagnosis is not likely to be piezogenic pedal papules. These growths, caused by fat herniations through defects in the dermis, are usually seen on the heels, are smooth, and disappear when the person takes weight off their feet. Our patient's growths were on the outside of the skin.

Although an unlikely diagnosis, squamous cell carcinoma (SCC) should be included in the differential because it can be caused by HPV and our patient has multiple risk factors because of a renal transplantation. However, SCC is most commonly found on the head, neck, and upper extremities.

Corns usually occur on the toes secondary to persistent friction or pressure. Corns can be painful when performing weight-bearing activities like walking or standing. However, skin lines are preserved. Corns have a clear center and lack thrombosed capillaries when pared down with a scalpel.

Treatment Plantar warts can occur as a single, discrete lesion or may coalesce and appear in a plaquelike configuration on the plantar surface of the feet. When plantar warts are pared down, an interruption of skin lines and the characteristic seeds are seen on the wart. Paring often causes fresh, pinpoint bleeding as intact capillaries are transected, a finding unique to warts.

Initial treatment is usually cryotherapy with liquid nitrogen. Surgical excision and laser therapy are other treatment modalities. Biologic modalities involve inducing immune responses and, therefore, are not recommended for transplant-recipient patients. Chemical treatments can be used in combination with cryotherapy. In nonimmunosuppressed patients, cure rates can be as high as 80%.1 In many renal transplant recipients, the goal is to keep warts under control because chronic immunosuppression makes a cure unrealistic. JAAPA

Joe R. Monroe, PA-C, MPAS, department editor

REFERENCE

1. Marks J, Miller J. Lookingbill & Marks' Principles of Dermatology. 4th ed. Philadelphia, PA: Saunders Elsevier; 2006.

Cheryl Green works in primary care at Lebanon VA Medical Center, Lebanon, Pennsylvania. Ms. Green also works part time in a family medicine practice in Lancaster, Pennsylvania. She has indicated no relationships to disclose relating to the content of this article.