Additional Skin Cancers
While melanoma, basal cell carcinoma, and squamous cell carcinoma are more common, there are other types of skin cancers, such as the following.
Dermatofibrosarcoma protuberans (DFSP)
Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade, soft-tissue, undifferentiated mesenchymal tumor, which arises in the dermis and invades deeper underlying soft tissue. It is associated with high risk for local recurrence and widespread subclinical extension. The incidence of DFSP is 0.1 percent of all cancers and 1.8 percent of all soft tissue sarcomas.
DFSP occurs most often in adults aged 20-50 years with pediatric and infantile cases (particularly congenital ones) being much less frequent. The tumor most commonly involves the trunk (50-60 percent) and upper limbs (25 percent); head and neck sites account for 10-15 percent of DFSP cases. If left untreated, the tumor grows slowly, invading surrounding tissue as well as neurovascular bundles. Although DFSP can be locally destructive the tumor rarely metastasizes.
Surgical excision remains the mainstay of treatment for DFSP. A wide excision of 2-3 cm or more of the margins beyond the clinically identifiable tumor border, down to and including the fascia, is recommended. Despite wide local excisions, an average recurrence rate of 15.7 percent is still observed among body cases and 51.8 percent is observed among head and neck cases. A superior cure rate (an overall average recurrence rate of 1.3 percent among 463 cases reported) and tissue conservation are seen when Mohs micrographic surgery is used, making this type of surgery the treatment of choice, particularly when a lesion is located in the head and neck region.
Advanced DFSP Treatments
In 2006, the FDA granted approval for a tyrosine kinase inhibitor, imatinib mesylate (Gleevac), as a single agent for the treatment of adult patients with unresectable, recurrent, and/or metastatic DFSP. The recommended oral dose is 800 mg/d. Adjuvant radiotherapy (RT), administered either before or after surgery, significantly reduces the risk of local recurrence in patients who have or who are likely to have close or positive margins.
Sweat Gland Tumors
Sweat gland tumors (also called syringomas) are rare, benign skin lesions that most frequently form as tiny bumps 1-3 mm in diameter. Typically appearing on or near the eyelids, they can also form on other areas of the body such as the armpits, vulva, and lower abdomen.
The current treatments for sweat gland tumors include localized approaches, such as surgery. In unresectable disease, chemotherapy can be considered on a case by case basis. Given the rarity of these malignancies, patients should discuss the optimal approach with a dermatologist or oncologist.