VANCOUVER, B.C. — Adenosquamous carcinoma often is a misdiagnosed, more aggressive type of skin cancer, which requires close follow-up for possible recurrences, according to a review that identified 27 patients with primary adenosquamous carcinoma.
As skin cancers go, adenosquamous carcinoma (ASC) is somewhat newly recognized and uncommon, observed Dr. Jennifer M. Fu, a dermatology resident at the University of California, San Francisco.
“We are starting to get the sense that it can be very clinically aggressive and, in fact, may be more aggressive than conventional cutaneous squamous cell carcinoma [SCC], with a high risk of local recurrence and, in some case series, distant metastases,” Dr. Fu said at the annual meeting of the American College of Mohs Surgery.
A rise in the number of cases at her institution in recent years, with some of them proving to be very locally aggressive, prompted a closer look at this cancer. Dr. Fu and her colleagues searched their institution's records for the past 10 years to identify cases of ASC diagnosed there. The search identified 27 patients with primary ASC, 7 of whom experienced a recurrence. The patients had a mean age of 74 years (range 50–97 years), and 70% were men.
Some 56% of the primary tumors were on the face, 15% were on the scalp, and 15% were on the arm or shoulder. “Clinically, this was a very difficult diagnosis for people to make, often presenting just as a firm papule or plaque and not infrequently ulcerated,” Dr. Fu said.
“Most of the clinicians diagnosed this as something else—as basal cell carcinoma, scar, metastatic carcinoma, rosacea in one case, and a spider bite in another case,” she said, adding that SCC was listed in the differential diagnosis in only four cases. “In no case was adenosquamous carcinoma correctly diagnosed,” she said.
Clinical outcomes were assessed in the six patients who received most of their treatment at her hospital. Five were immunosuppressed. All underwent Mohs surgery at least once, and two received adjuvant therapy consisting of radiation therapy and cetuximab (Erbitux) for locally advanced disease. For all of these patients, “the Mohs defect postoperatively far exceeded what was evident clinically,” she noted.
Two patients were alive with no evidence of disease, and another patient with brief follow-up (5 days) was alive with persistent disease. The remaining three patients had locoregional recurrences 3 months, 4 months, and 5.5 years after their primary tumor, but there were no cases of distant metastases. Two of these three patients with recurrences were alive with no evidence of disease after 4 and 4.5 years, while one was alive with unclear disease status after 3.5 years.
Dr. Fu reported that she had no conflicts of interest in association with the study.
Recurrent ASC nodules/plaques are visible at the edge of a scar from previous treatment. University of California, San Francisco/Department of Dermatology