In one case, the small scalp lesion was barely pink, ill defined, and bound down to the adjacent skin. "No way I thought this was a Merkel cell," he admitted.
When the diagnosis is confirmed by its blue cell clusters in sheets or a trabecular pattern in the dermis, with frequent mitosis and cell necrosis, dermatologists should take heed. "This is probably one of the worst cutaneous tumors that we, as dermatologists, can see. It's right up there with a bad angiosarcoma," he said.
Local recurrences are seen in 25%-33% of cases, regional spread in 25%, and distant metastasis in 33% of cases50% by some reportswith a 3-year overall survival of 31%.
Treatment is controversial, noted Dr. Brown. Wide local excision down to the fascia or Mohs surgery with sentinel lymph node biopsy is recommended, guiding the need for total lymph node dissection, postoperative radiation therapy, and perhaps adjuvant chemotherapy. A negative sentinel lymph node carries a fairly reassuring prognosis.
He added that an immunostain for anti-CK20 antibody may detect micrometastases in patients who appear to be tumor free on routine histology, according to a small study (J. Am. Acad. Dermatol. 2002;46:6616).
SCC in Organ Transplant Patients
The growing population of long-term survivors of organ transplantation has a 65-fold increased risk of squamous cell carcinoma.
Their cancers may be multiple, fast growing, and atypical in appearance, Dr. Brown said.
In one such case, a liver transplant patient he had seen 3 weeks previously presented with a 3-cm SCC at the base of his thumb. He had a positive lymph node in his axilla and developed metastatic disease in his lung within 3 months.
"We're all going to be seeing more and more of these patients," Dr. Brown predicted.
The keys to management of these challenging patients are education first, then vigilance. Many transplant centers fail to warn patients that they may be at elevated risk for skin cancers and that they should be examined frequently.
When a lesion appears, have a low threshold for suspicion, he said. "It is very difficult sometimes to determine which is the bad [lesion] and which is not."
High-risk SCCs are those that are large, multiple, deeply invasive, painful or tender, rapidly growing, recurrent, and on high-risk sites: the scalp, ear, lip, neck, and face. Warning signs histologically include poor cell differentiation and perineural invasion.
"How do you manage these? Aggressively," he emphasized.
Employ whichever tools work: surgery, cryotherapy, 5-fluorouracil, photodynamic therapy, or topical imiquimod. Systemic retinoids, perhaps in conjunction with a reduction in immunosuppressive therapy, may be appropriate for patients with recurrent, aggressive, or metastatic SCCs, he added.
Dr. Brown disclosed that he is a consultant to Graceway Pharmaceuticals LLC and Novartis. His presentation, however, was not sponsored by any company.
Long-term survivors of organ transplantation have a 65-fold increased risk of squamous cell carcinoma. DR. BROWN