Co-occurrence of Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma and Head and Neck Squamous Cell Carcinoma: A Single-Institution Study

In patients with squamous cell carcinoma of the head and neck, co-occurring chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is not uncommon. Given the often subtle histopathologic features, this diagnosis may go unrecognized by the pathologist. This study aims to investigate the high rate of co-occurrence of CLL/SLL and head and neck squamous cell carcinoma and to illustrate the combination of clinical and histopathologic findings in these patients. A retrospective single-institution review was conducted of 3524 pathologic diagnoses of head and neck squamous cell carcinoma, from which 24 patients with concurrent diagnoses of CLL/SLL were identified. Squamous cell carcinomas for these 24 patients were restaged, and the histopathologic and immunohistochemical profiles were assessed. Concurrent cutaneous squamous cell carcinoma was identified in 21 out of 24 patients, with oropharyngeal squamous cell carcinoma in the remaining 3. Nine patients had nodal metastases. Fine-needle aspiration biopsy was performed in 15 out of 24 patients and rendered the diagnosis of squamous cell carcinoma in 9 patients and CLL/SLL in 6 patients. Co-occurring CLL/SLL is easily missed in biopsies and neck dissections performed for the diagnosis and management of head and neck squamous cell carcinomas. Awareness of the pertinent morphologic features should prompt additional immunohistochemical studies that can lead to a definitive diagnosis.