Maintaining a high index of suspicion for sebaceous carcinoma is important in those patients who present with certain periocular lesions, because sebaceous carcinoma can be an aggressive tumor that's often misdiagnosed, says Marc Brown, M.D.
"Diagnosis of sebaceous carcinoma is often delayed by one to three years because it can mimic various common, benign eye conditions, particularly chalazion or kerato- or blepharoconjunctivitis, and it can also be mistaken for basal cell and squamous cell carcinoma," says Dr. Brown, professor of dermatology and oncology, University of Rochester Medical Center, Rochester, N.Y.
"Therefore, it is important to be familiar with the features and risk factors for sebaceous carcinoma and to consider the diagnosis in a patient with a persistent chalazion or unilateral kerato- or blepharoconjunctivitis. Biopsy any suspicious lesion, but know your dermatopathologist, because histopathological misdiagnosis can occur, and treat sebaceous carcinoma aggressively with surgery, because it is one of the most lethal of all eyelid malignancies," he says.
Awareness of the features of sebaceous carcinoma aids diagnostic suspicion. The tumors are more common in older people (usually sixth to seventh decade of life). Periocular sebaceous carcinomas also develop more often in women, particularly among people of Asian descent.
Periocular sebaceous carcinoma more often involves the upper versus lower eyelid. It presents as a painless, slowly enlarging nodule that is typically yellowish to pink/red in color. Other findings that should raise suspicion for sebaceous carcinoma include loss of cilia, yellow streaking on the conjunctiva, increased vascularity and unilateral inflammation.
"Everting the eyelid may be helpful for visualizing the lesion, and there may be cutaneous irritation from pagetoid spread of the cancer onto the cutaneous surface," Dr. Brown says.
Although there is no question that sebaceous carcinoma can be a highly aggressive tumor, its metastatic rate is controversial. The rate has been reported to be as high as 25 percent, but more recent data suggests it is more in the range of 10 percent. Metastasis usually occurs to the regional lymph nodes, and once the disease becomes metastatic, the five-year mortality rate has been reported to be 50 to 60 percent.
"Survival among patients with metastatic sebaceous carcinoma appears to have improved more recently, perhaps due to greater awareness of this tumor leading to earlier diagnosis, Dr. Brown says.
Evidence of ocular invasion, lacrimal gland involvement or pagetoid spread, as well as poorly differentiated histology, large size (>10 mm) and persistence of symptoms for more than six months are indicators of a poorer prognosis. Upper-lid lesions also tend to have a worse prognosis than lower-lid sebaceous carcinomas, he says.