Our patient had a history of osteosarcoma of the proximal tibia that presented with painful swelling of the left lower leg area. There was no evidence of tumor recurrence or distant metastases until a mass inside the external auditory canal was found 1 year after the patient completed the treatment course.
Examples of metastatic tumors to the temporal bone presenting in the external auditory canal are extremely rare in the English-language literature. In a review of 165 cases of metastatic tumors involving the temporal bone, the most common sources were the breasts (29%), lungs (11%), prostate gland (8%), unknown primary origin (8%), and kidneys (6%).1,2 Other sites, such as the esophagus, stomach, rectum, thyroid, cervix, vagina, urinary bladder, and larynx, have also been reported.1-5 Metastatic tumors to the external auditory canal are even rarer. The incidence, therefore, remains unknown, perhaps owing to the lack of routine postmortem study of temporal bone and also because metastatic neoplastic deposits in this area may remain latent during the lifetime of the patient.1 According to our review, metastasis of sarcomatous tumors to the external auditory canal has been documented only once, by Pfleiderer et al6 in 1992. The authors reported a case of metastatic osteosarcoma presenting as a bleeding aural polyp, which arose from a primary lesion in the tibia in a patient with Paget disease.