Objective To investigate the characteristics and diagnosis of malignant proliferating trichilemmal tumor (MPTT) in the external auditory canal, in order to reduce clinical misdiagnosis and omission. Methods We retrospectively analyzed the clinical manifestations of MPPT, explored its etiology with the help of ancillary examinations and pathological findings, and made the diagnosis of the disease by combining the case data. Results MPPT has been reported rather rarely and is usually easily confused with squamous cell carcinoma, which has common features but has a tendency to metastasize and recur more frequently than squamous cell carcinoma. Therefore, accurate clinical judgment of this condition is very important for the implementation of subsequent therapeutic means. Conclusion Only by being familiar with the clinical characteristics of MPPT and with the help of appropriate detection methods can we make a rapid diagnosis and thus develop a treatment plan.