Atypical granular cell tumor of the larynx: an unusually aggressive tumor clinically and microscopically.

A 36-year-old man presented with a recurrent, rapidly enlarging laryngeal tumor causing upper airway obstruction. Microscopic study revealed a granular cell tumor (GCT) with marked atypia, pleomorphism, and pagetoid spread to the overlying epithelium. Histologic pleomorphism occurs rarely and is usually mild in laryngeal GCT. Malignant granular cell tumor (MGCT), a very unusual entity, can be diagnosed with confidence when there is clinical evidence of malignancy (i.e., metastasis). We support the concept of "atypical" GCT when marked pleomorphism is present, yet no metastasis has occurred. This will indicate to the otolaryngologist and pathologist the possibility of greater potential for aggressive clinical behavior.