Branchial Cleft Cyst Carcinoma Remains Grossly Over Diagnosed: A Large Database Analysis

ABSTRACT Introduction Branchial cleft cyst carcinomas (BCCC) are rare lateral neck malignancies thought to originate from branchial cleft remnants. Diagnosing primary BCCC should be approached with skepticism; cystic nodal metastasis must be excluded. Due to its rarity, we performed a comprehensive database study to better characterize the ongoing diagnosis of BCCC. Methods Single‐arm retrospective cohort study using the TriNetX Research database. Patients ≥ 18 years of age with a diagnosis of BCCC identified by ICD‐10 C10.4 between 2008 and 2018 were included, allowing for up to 5 years of follow‐up. Demographics, past medical history, oncologic history, diagnostic rate, treatment pathways, and 5‐year outcomes including diagnosis with primary HNC and Kaplan–Meier survival curves were analyzed within TriNetX. Results In 10 years, 1070 patients diagnosed with BCCC were included. The mean age was 59.6 ± 9.7; the majority were male ( n = 810, 75.6%) and white ( n = 765, 71.4%). Incidence of BCCC increased from 2008 to 2015 and subsequently dropped precipitously. Almost all patients, 94.4% ( n = 1011), had prior or subsequent diagnosis of another HNC within 5 years. Five‐year survival probability for BCCC was 56.0%. Conclusions We describe the largest cohort of BCCC patients to date. Most patients were diagnosed with another HNC within 5 years, suggesting a likely misdiagnosis of BCCC. A poor 5‐year survival rate may be secondary to a delay in appropriate treatment following an erroneous diagnosis, underscoring the need to approach a diagnosis of BCCC with caution. We consider the use of the BCCC code to be detrimental and recommend its discontinuation. Level of Evidence 4.