Elderly man with rapidly enlarging axillary mass.

Melanoma has long been known to be a malignancy that can present in a plethora of forms. This often makes diagnosing it a challenge, but lends support to the concept of frequently keeping it in the clinician's differential. We present the unique case of a rapidly enlarging axillary mass in an elderly man that initially did not appear concerning for malignancy. Pathologic diagnosis was particularly difficult due to the cystic nature of the mass, and the uncommon histo-chemical staining pattern of this malignant melanoma. We discuss the variety of therapies directed at symptom relief and control when discovered in advanced stages. This was a rare presentation of a malignant melanoma that highlights the need to maintain a suspicion for the disease in uncertain clinical situations.