Rare Types of Skin Cancer You May Not Have Heard Of

Most people are familiar with basal cell carcinoma, squamous cell carcinoma, and melanoma. However, there are also several less common skin cancers that may behave differently and sometimes require specialized treatment.

Although rare, these tumors are important because some can grow aggressively or be mistaken for more common skin conditions.

Sebaceous Carcinoma

Sebaceous carcinoma is an uncommon tumor that arises from oil glands in the skin. It most commonly occurs around the eyelids but may also appear elsewhere on the face or body.

Because it can sometimes resemble benign growths or inflammation, diagnosis may occasionally be delayed.

Dermatofibrosarcoma Protuberans (DFSP)

DFSP is a rare soft tissue tumor that typically grows slowly over time. It may initially appear as a firm plaque or thickened area of skin before becoming more raised.

Although DFSP rarely spreads to distant organs, it can extend deeply into surrounding tissues if left untreated. Mohs surgery is considered the gold standard for the treatment for DFSP.

Atypical Fibroxanthoma (AFX)

AFX is an uncommon tumor that often develops on sun-damaged skin in older individuals, particularly on the scalp, ears, or face. These lesions may grow relatively quickly and can sometimes resemble other skin cancers clinically.

Although AFX is often considered relatively indolent, local recurrence may occur if the tumor is not completely removed. Because of this, treatments with complete margin evaluation, such as Mohs surgery, may sometimes be recommended.

A related but more aggressive entity, pleomorphic dermal sarcoma (PDS), may extend more deeply into surrounding tissues and has a greater potential for recurrence or metastasis.

Microcystic Adnexal Carcinoma (MAC)

Microcystic adnexal carcinoma is a rare sweat gland tumor that most commonly occurs on the face. These tumors may appear subtle on the surface while extending more deeply beneath the skin.

Because of their infiltrative growth pattern, specialized surgical treatment, such as Mohs surgery, is usually recommended.

Extramammary Paget Disease

Extramammary Paget disease is a rare condition that often affects areas such as the groin or genital region. It may resemble chronic eczema, irritation, or rash-like inflammation and can sometimes persist for long periods before diagnosis.

In some cases, extramammary Paget disease may be associated with underlying internal malignancies involving the gastrointestinal or genitourinary systems, which is one reason thorough evaluation may be recommended.

Merkel Cell Carcinoma

Merkel cell carcinoma is a rare but potentially aggressive skin cancer that often develops on sun-exposed skin in older adults.

Treatment may involve surgery, radiation therapy, and sometimes immunotherapy, often in coordination with multiple specialists.

Final Thoughts

Although these cancers are uncommon, persistent or unusual skin lesions should still be evaluated by a physician, particularly if they continue growing, changing, bleeding, or failing to heal.