Metastatic basal cell carcinoma may be under-diagnosed

Key Points

Washington - Basal cell carcinoma is a skin tumor that is quickly diagnosed, easily managed and curable if treated quickly. However, according to one specialist, metastatic BCC likely occurs much more frequently than currently reported, and dermatologists should consider metastatic lesions and address them accordingly.

"As a practicing dermatologist and as an attending in a residency program faculty, I find that there are more and more cases of metastatic basal cell carcinoma, much more than are currently being reported in the literature," says Vincenzo Giannelli, M.D., assistant clinical professor of dermatology, department of dermatology, Washington Hospital Center, Georgetown University Hospital, Washington.

A search of the current literature shows that only about 350 cases of metastatic BCC (MBCC) have been reported. However, with 1 million new cases of BCC every year in the United States alone, Dr. Giannelli says it is very hard to believe, and highly unlikely, that these metastases do not occur more frequently than they are actually reported. Dr. Giannelli recently reported on three cases of metastatic BCC.

Patient one was a 52-year-old female who presented with a BCC of the right lateral cheek with perineural invasion of the marginal mandibular branch of the facial nerve. The tumor was removed using Mohs in two stages. During the second stage, tumor invasion of the marginal mandibular nerve was noted. The patient then underwent a deeper resection of the gross disease with facial nerve preservation. She later presented with multiple nodules on the back, and PET-CT revealed innumerable foci of skeletal and soft tissue metastases of BCC with no pulmonary or major organ involvement.

Patient two was a 72-year-old male who presented with a BCC of the left antecubital fossa. The patient had a 10-year history of multiple incidences of several BCCs excised from the left chest and a recurrent infiltrative BCC of the right nasal wall. During an evaluation of congestive heart failure, a solitary nodule was discovered in the left posterior lung. A new pulmonary nodule in the left upper lobe was discovered the following year. Computed tomography-guided lung biopsy of the tumor showed similar histological features of both the first pulmonary nodule and the infiltrative BCC excised from the right nasal wall 10 years prior.

Patient three was a 44-year-old male who presented with BCC of the forehead which had partially eroded through the outer table of the frontal bone. During a follow-up evaluation, a CT scan of the neck and parotids revealed three nodules in the right parotid gland and one in the left gland, all of which were confirmed as MBCC by fine needle aspiration cytology.

Metastasis

BCC metastasis to the lung is considered the most feared complication, carrying the worst prognosis. Dr. Giannelli says although the overall incidence of MBCC is rare, a metastatic work up is warranted, especially in cases with perineural invasion or involvement of bone. Aggressive histologic BCC subtypes and lesions located in the central face and head and neck area, especially in areas that follow the embryological cleavage lines, seem to be most commonly associated with MBCC.

"Infiltrative BCCs have a high potential of metastasis; however, the location of the BCC, regardless of the histologic type, is very often associated with possible metastases of BCC in the future. The majority of BCC patients show a distribution to the head and neck area, and the correlation with metastatic BCC is even higher in this patient population," Dr. Giannelli says. "The central face appears to be particularly associated with metastases and is likely due to the embryonal clefting as well as the lymphatic and hematological spread associated with these primary tumor sites."

Many dermatologists do not consider MBCC as a real possibility, probably due to its suspected rare occurrence. However, Dr. Giannelli says patients who have multiple and/or recurrent BCCs, particularly located in the central face region, and those who have been treated with radiation (which has also been associated with an increase in metastatic spread of BCC) must be screened much more closely for the chance of MBCC.

Intense screening

In this patient population, Dr. Giannelli considers a chest X-ray and performs a thorough skin exam including lymph node palpation in order to rule out the possibility of metastasis. This more intense screening protocol is already being readily practiced in melanoma as well as squamous cell carcinoma patients, and should become a mainstay in BCC patients in whom the potential of metastasis is higher.

"I sincerely hope that more colleagues will screen more thoroughly for potential MBCC, as I believe that they are grossly under-reported. I believe that in the future, the goal of therapy in patients with recurrent and/or a history of aggressive BCC tumors lies in tumor markers associated with these metastases.

"We would be able to much more effectively target these tumors and prevent lung metastases, which are the ones that have the worst prognosis, and can, therefore, take better care of our patients," Dr. Giannelli says.

Disclosures: Dr. Giannelli reports no relevant financial interests.