Entamoeba gingivalis identified in a left upper neck nodule by fine-needle aspiration: a case report.

We present a unique case of a 37-yr-old patient who underwent a left partial glossectomy, modified neck dissection, and radiation therapy in December 1990. In June 1991 the patient developed a 0.6 cm erythematous nodule in the left upper portion of her neck adjacent to the surgical scar. A fine-needle aspiration (FNA) of the nodule was performed. Cytologic examination revealed the presence of numerous organisms morphologically consistent with Entamoeba gingivalis. Although E. gingivalis can be found in specimens from the oral cavity, especially following radiation, it is rare to find these organisms within lesions of the head and neck region. In this case, it is believed that the patient had an increased number of organisms within her oral cavity secondary to radiation therapy. Radiation therapy also may have contributed to the formation of a fistula tract between the oral cavity and the surgical incision site which resulted in the formation of a small inflammatory nodule in the upper portion of the neck. The organisms could then travel from the oral cavity to the nodule in the neck thus explaining their presence in the FNA material.