Challenges in Achieving a Definitive Diagnosis of External Auditory Canal Squamous Cell Carcinoma.

Objective: Squamous cell carcinoma (SCC) of the external auditory canal has a favorable prognosis when complete resection with negative margins is achieved. Early diagnosis and timely referral to specialized centers are crucial. However, definitive diagnosis is often delayed due to challenges in timely referral and the need for multiple biopsies. This study aims to examine the diagnostic trajectory of SCC of the external auditory canal, focusing on the number of biopsies required and the process leading to definitive diagnosis.

Study design: Retrospective case review and descriptive study.

Setting: Tertiary referral center.

Patients: We conducted a retrospective case review at a tertiary referral center, analyzing 56 cases of SCC of the external auditory canal treated between January 2015 and February 2024.

Interventions: Medical records were retrospectively reviewed.

Main outcome measures: The course of events leading up to their visit of our hospital, the number of biopsies performed to be diagnosed, and the histopathological findings.

Results: The time from initial presentation to referral ranged from 1 to 785 days (mean: 170.6 d; median: 130 d). A definitive diagnosis was achieved with the first biopsy in 35 cases (62.5%), whereas 21 cases (37.5%) required multiple biopsies. Only 21.4% of the cases were definitively diagnosed at the initial presenting facility, whereas 32.1% were diagnosed at our hospital. More than 90% of the tumors were well-differentiated or well-to moderately/poorly differentiated SCC. The number of biopsies required to confirm a definitive diagnosis was significantly associated with longer delays in hospital referral (correlation coefficient: 0.3122, p = 0.0192). Two cases of the hyperkeratotic SCC were presented as representative cases in which a definitive diagnosis was challenging.

Conclusion: Early diagnosis of SCC of the external auditory canal relies on thorough biopsy evaluation. Given the tumor's tendency for high differentiation, obtaining biopsy samples with clear malignant features is critical for making an accurate and timely definitive diagnosis.