Because verrucous carcinoma and ILVEN can have striking histologic similarities, one expert recommends considering verrucous carcinoma in the differential diagnosis of ILVEN. Initial biopsies can be misleading, evidence from this case demonstrates.
The case furthermore suggests that physicians consider verrucous carcinoma in the differential diagnosis of ILVEN, he adds.
"This case is unique because initial biopsies showed a histologic picture consistent with ILVEN," says Ramsay S. Farah, M.D., associate professor of medicine and pathology, department of medicine, division of dermatology (and section chief of dermatology), State University of New York Upstate Medical University, Syracuse. However, he says, "The real diagnosis was of a verrucous carcinoma. ILVEN has never before entered into the histologic differential diagnosis of a verrucous carcinoma."
Three years later
The patient returned three years later with extensive verrucous, fungating patches on her labia majora bilaterally. "The patient was not getting better," he states, "so punch biopsies were done and sent out in consultation to a premier dermatopathologist." The dermatopathologist interpreted the samples as epidermal nevus with abnormal dyskeratosis and psoriasiform features, and he made a diagnosis of ILVEN with overlying psoriasis, Dr. Farah tells Dermatology Times.
Based on this diagnosis, Dr. Farah treated the patient with methotrexate and topical triamcinolone. But after 17 months of this therapy, the patient still had growing papillomatous lesions on her labia, although the psoriatic lesions on her scalp, elbows, palms and soles showed clinical improvement, he says.
The patient eventually underwent bilateral vulvectomy. The excised specimens proved to be superficially invasive verrucous carcinoma, he says.
The case illustrates that it can be tricky to distinguish verrucous carcinoma from ILVEN, Dr. Farah observes. "One of the best dermatopathologists in the world was fooled by this case. If it can trick him, it can trick anyone," he says. Accordingly, Dr. Farah recommends that dermatopathologists and clinicians add the histologic features of ILVEN as possible masqueraders to verrucous carcinoma. "The more awareness there is," he says, "the smaller the chance of a misdiagnosis and delay in treatment."
In this case, he says the initial punch biopsy proved misleading because it showed the classic alternating keratinization pattern considered characteristic, but not pathognomic, for ILVEN. However, Dr. Farah says examination of resected vulvar tissue revealed an exo-and endophytic growth pattern characteristic of verrucous carcinoma.
Disclosure: Dr. Farah reports no relevant financial interests.