Diagnosis: Verruciform Xanthoma
SAN FRANCISCO Physicians performed several biopsies of the noncrusting, nonulcerating plaque over a period of several months, looking for possible squamous cell carcinoma. Results were negative for cancer but did show epidermal acanthosis.
This and other characteristics seen on histology identified the plaque as verruciform xanthoma, an uncommon and usually benign entity that has been associated with recessive dystrophic epidermolysis bullosa in only three previous case reports, Dr. Kathie Huang reported at the annual meeting of the Pacific Dermatologic Association.
Verruciform xanthoma can mimic squamous cell carcinoma and warrants a biopsy for evaluation.
Atypia and carcinoma can arise within verruciform xanthoma, according to rare case reports, so it requires close follow-up, said Dr. Huang of Stanford (Calif.) University.
One previous report recommended surgical excision of the lesion to avoid any remote risk of carcinoma, and others called for close follow-up.
In the current case, low-power magnification revealed epidermal acanthosis, papillomatosis, and hyperkeratosis.
On closer inspection, pathologists could see neutrophilic infiltrate within the epidermis and to the parakeratotic stratum corneum, and clear foamy xanthoma cells filling the papillary dermis. Higher magnification showed clear foamy xanthoma cells in the papillary dermis.
The boy's verruciform xanthoma lesion was surrounded by a difficult-to-heal wound. Recessive dystrophic epidermolysis bullosa is characterized by skin fragility, recurrent trauma, and impaired wound healing.
During trials of treatment with imiquimod, topical antibiotics, and a topical steroid, the verruciform xanthoma plaque maintained its color and quality, and increased some in size before stabilizing.
Dr. Huang and the attending physician, Dr. Anna Bruckner of the university, said they feared that excision of the lesion would increase morbidity by resulting in a nonhealing wound because of the patient's recessive dystrophic epidermolysis bullosa and malnutrition. They opted to manage with close follow-up.
The patient now is 14 years old and doing well, Dr. Huang reported. The verruciform xanthoma plaque has not changed significantly, and has no ulceration or crusting.
In general, verruciform xanthoma usually is found in the oral mucosa, but also has been seen in the anogenital area and other sites. It also can arise in special settings, such as in patients with chronic lymphedema on the legs, recessive dystrophic epidermolysis bullosa, or other conditions.
The etiology is poorly understood. Trauma, irritation, and infection are thought to be contributors to verruciform xanthoma.
One case report associated the disease with human papillomavirus (HPV) infection, but several subsequent case series found no association with HPV, "so it's currently thought not to be related" to HPV, she said.
Pathologists were able to see neutrophilic infiltrate within the epidermis and to the parakeratotic stratum corneum, and clear foamy xanthoma cells in the papillary dermis (at high magnification). Courtesy Dr. Kathie Huang