Endoscopic ultrasound guided fine-needle aspiration (FNA) of the upper gastrointestinal tract presents a diagnostic challenge to cytopathologists due to the broad differential diagnosis and morphologic overlap between various entities in this location. We report here an incidentally discovered case of esophageal glomus tumor presenting as a posterior mediastinal mass in an 80-year old male. Glomus tumor is a rare soft tissue neoplasm with bland epithelioid morphology and cytoplasmic granularity. Literature review reveals only 6 published cases of esophageal glomus tumor in the general pathology literature. To our knowledge, this is the first report in the English literature to describe FNA cytology of an esophageal glomus tumor. This rare case presentation provides the opportunity to review the differential diagnosis for lesions of the upper gastrointestinal tract and their appearance on FNA in order to clarify an entity that is uncommon in everyday cytology practice. Diagn. Cytopathol. 2014;42:705–710. © 2013 Wiley Periodicals, Inc.