What is the management approach for postauricular (behind the ear) benign tumors?

Management of Postauricular Benign Tumors

The management of postauricular benign tumors should be based on tumor size, symptoms, and specific characteristics, with observation being the first-line approach for small asymptomatic tumors, while surgical intervention or stereotactic radiosurgery are recommended for symptomatic or larger tumors. 1

Assessment and Diagnosis

• Initial evaluation should include MRI and audiological assessment to determine tumor size, location, and impact on surrounding structures 2
• Tumors are classified using the Koos grading system (I-IV) based on size and extension, which guides treatment decisions 2
• Multidisciplinary tumor board discussion is recommended for comprehensive evaluation, especially for medium-sized tumors 1

Management Algorithm Based on Tumor Size and Symptoms

Small Asymptomatic Tumors (Koos grades I-II)

• Observation with serial MRI and audiological monitoring is the management of choice for small asymptomatic tumors (evidence level III, recommendation level C) 2, 1
• Annual MRI follow-up for 5 years is recommended, with longer intervals thereafter if stable 2, 1
• Stereotactic radiosurgery (SRS) is an alternative to observation to stop tumor growth and preserve long-term nerve function (evidence level II, recommendation level B) 2, 1
• Surgery is not recommended for small asymptomatic tumors due to high risk of functional deterioration (up to 50%, evidence class III, recommendation level C) 2

Small Tumors with Complete Hearing Loss (Koos grades I-II)

• Observation is usually the first option since no function is endangered for a long period (evidence class III, recommendation level C) 2
• SRS carries a lower risk profile than surgery, making it the first option if tumor control is sufficient (evidence class II, recommendation level B) 2
• Surgery can be considered for definitive treatment but carries higher risks 2

Medium-Sized Tumors (Koos grades III-IV, <3 cm)

• Active treatment is recommended due to symptomatic burden and tumor volume 2
• Both surgery and radiosurgery can be recommended (recommendation level C) 2
• SRS has a lower risk profile but surgery offers complete tumor removal 2
• Subtotal resection to preserve function may be an option if subsequent SRS of a growing tumor remnant can be provided 2

Large Tumors with Brainstem Compression (Koos grade IV, >3 cm)

• Surgery is the only option for primary decompression of the brainstem and stretched cranial nerves 2
• Subtotal resection followed by SRS or observation is a valid option to reduce risks of cranial nerve damage (evidence class IV) 2

Surgical Approaches

• If surgery is indicated, treatment at a high-volume center is recommended since surgical experience affects outcomes (evidence class IV) 2, 1
• Endoscope-assisted resection via concealed post-auricular sulcus incision shows advantages of faster recovery and better cosmetic outcomes compared to conventional approaches 3
• This minimally invasive approach results in shorter incisions (4.0±0.4 cm vs. 10.3±1.6 cm), less blood loss, and higher patient satisfaction 3

Follow-up Recommendations

• Annual MRI and audiometry for 5 years, then every 2 years if stable, for conservatively managed, radiated, and incompletely resected tumors 2
• For gross total resection, MRI controls postoperatively and after 2,5, and 10 years are sufficient 2
• Shorter follow-up intervals (6-12 months) are recommended for patients with neurofibromatosis type 2 (NF2) 2

Special Considerations

• Quality of life outcomes cannot be predicted based on management strategy alone 1
• Poor quality of life is more likely in patients with large, symptomatic tumors that require resection 1
• For patients with NF2 and bilateral vestibular schwannomas, bevacizumab shows positive effects on hearing and tumor growth (evidence class II, recommendation level B) 2

Treatment Pitfalls and Caveats

• Risk for tumor regrowth after subtotal resection increases with residual tumor volume 1
• Even after 5 years of stability, 7.2% of tumors may exhibit growth, necessitating long-term follow-up 2
• Facial nerve preservation should be prioritized during surgical management, as facial nerve palsy can lead to significant complications including exposure keratopathy and corneal damage 2
• Pseudoprogression on imaging after SRS should be evaluated by specialists from multiple disciplines to avoid unnecessary interventions 2