SYDNEY, AUSTRALIA – Watchful waiting may not be the safest approach for managing patients with desmoplastic trichoepithelioma, according to a speaker at the annual meeting of the Australasian College of Dermatologists, who described five cases of the benign tumor combined with basal cell carcinoma.
Desmoplastic trichoepithelioma (DTE), a rare benign tumor that typically presents as a small, slow-growing, asymptomatic, skin-colored lesion on the face, with a depressed nonulcerated center and often raised edges, is managed with watchful waiting or local excision. While its key histopathologic features are narrow cords or strands of basaloid cells, numerous small keratin-filled cysts, and a surrounding desmoplastic core, DTE can be confused with morpheaform basal cell carcinoma (BCC), Tristan Blake, MD, dermatology registrar at Royal Brisbane and Womens’ Hospital, Brisbane, Australia, said at the meeting.
Dr. Tristan Blake
“At this stage, there’s no way to confidently say, looking at the slides, if those cases were desmoplastic trichoepithelioma arising in basal cell carcinoma or vice versa, or if they were a single tumor with divergent differentiation, or an occlusion of two separate tumors,” he said.
Dr. Blake added that this was the first time, to his knowledge, that such a combination had been reported, and that the finding had the potential to change the way DTE is managed.
“How can you now confidently elect to leave or watch the desmoplastic trichoepithelioma patients you have, knowing that not an insignificant portion might also harbor BCC or develop BCC in the future?” he said. This dilemma is made more acute by the fact that DTEs are typically found in younger patients and on the face, he added.
Two dermatopathologists involved in the retrospective review of cases reported that histochemistry was not particularly useful in differentiating DTE from other tumors, he noted.
Patients in the study were also interviewed about their tumors and reported no symptoms; when asked how long the lesions had been there prior to diagnosis, those who could recall said the lesions had likely been present for decades.
In an interview, Dr. Blake said that the discovery of coexisting DTE and BCC was a surprise, and cast doubt on the practice of watchful waiting.
No conflicts of interest were declared.