CYSTIC SQUAMOUS CELL CARCINOMAS OF THE JAWS: TWELVE CASES HIGHLIGHTING HISTOPATHOLOGIC PITFALLS

Abstract

<h3>Background and Objective</h3> Cystic squamous cell carcinomas (SCC) of the jaws, including carcinoma cuniculatum (CCu), are rare, slow-growing, and relentlessly invasive. The aim of this study is to document 12 cases. <h3>Methods</h3> Review of patient hospital notes, histopathologic reports, and original histologic sections. <h3>Results</h3> Six patients were female and 6 were male (mean age = 74.0 years; range, 50-94). Six tumors affected the mandible and 6 affected the maxillary alveolus with or without extension into the hard palate. Clinical presentation varied, ranging from relatively innocuous-looking ulceration to a grossly ulcerated mass, with radiological evidence of bony destruction in all cases. One patient had multiple dysplastic lesions and was retrospectively diagnosed with proliferative verrucous leukoplakia. For 2 others the tumor was a second primary oral SCC. Histologically, 4 of the 12 tumors were designated as CCu on the basis of deeply endophytic, anastomosing channels of cystic stratified squamous epithelium and keratin microabscesses. The other 8 were also cystic but more heterogeneous morphologically, and though a diagnosis of CCu had been considered in 5 of the 8 cases the final diagnosis was well-differentiated SCC. All patients underwent primary resection with neck dissection and were staged as T4a N0 M0. None developed any notable postoperative complications, but 4 patients died between 6 and 57 months after surgery. In 4 patients diagnosis was delayed as a result of superficial biopsies and/or confusing histopathology. <h3>Conclusions</h3> Cystic SCC of the jaws can be difficult to diagnose histologically. Clinico-radiological correlation and long-term follow-up are essential.