Squamous cell carcinoma in a patient with chronic lymphocytic leukemia - An intraoperative diagnostic challenge for the Mohs surgeon

BACKGROUND. Chronic lymphocytic leukemia (CLL) is the most common form of chronic leukemia in the US. CLL patients have an increased risk of developing other malignant neoplasms, especially skin cancer. Lymphoma-associated squamous cell carcinomas (SCCs) tend to behave more aggressively and therefore are often treated with Mohs micrographic surgery (MMS). OBJECTIVE. To elucidate the potential difficulty of distinguishing perineural infiltrates as leukemic infiltrates versus inflammatory infiltrates associated with SCC on frozen tissue sections during MMS. METHODS. This is a case report illustrating a patient with CLL who develops a SCC on the posterior ear. MMS was employed to treat the patient. Special immunohistochemical stains were performed to help distinguish the type of perineural infiltrate present. RESULTS. The perineural infiltrate was shown by immunohistochemistry to be leukemic in origin. Special stains for keratin revealed no residual SCC hidden in the infiltrate. CONCLUSION. CLL is a malignancy that primarily effects the elderly population and markedly increases their risk of developing skin cancers, especially SCC. An intense infiltrate may be present surrounding the tumor. This case report demonstrates one of the potential challenges the Mohs surgeon may face in interpreting histologic frozen section. Immunohistochemistry may be helpful in providing a more definitive answer to this problem. (C) 1998 by the American Society for Dermatologic Surgery, Inc.