Methods of Sentinel Lymph Node Identification in Auricular Melanoma

Area of Science:

• Oncology
• Nuclear Medicine
• Surgical Pathology

Background:

• Sentinel lymph node biopsy (SLNB) is crucial for staging auricular melanoma.
• Lymphatic drainage patterns of the ear are complex and poorly defined.
• Accurate sentinel node identification is vital for detecting micrometastasis.

Purpose of the Study:

• To define lymphatic drainage patterns of the ear in melanoma patients.
• To compare the accuracy of planar lymphoscintigraphy versus SPECT-CT for sentinel node identification.
• To evaluate the clinical impact of imaging modality on SLNB outcomes.

Main Methods:

• Retrospective review of 80 patients with auricular melanoma undergoing SLNB.
• Comparison of preoperative imaging (planar lymphoscintigraphy vs. SPECT-CT) with intraoperative findings.
• Analysis of sentinel node identification rates and locations (parotid/preauricular, mastoid/postauricular, cervical).

Main Results:

• Planar lymphoscintigraphy identified fewer sentinel nodes than intraoperative assessment in parotid/preauricular and mastoid/postauricular regions (P < 0.05).
• 32 unmapped nodes were found with planar lymphoscintigraphy, two positive for micrometastasis.
• SPECT-CT demonstrated perfect concordance between preoperative mapping and intraoperative identification.

Conclusions:

• SPECT-CT is superior to planar lymphoscintigraphy for preoperative sentinel node mapping in auricular melanoma.
• Planar lymphoscintigraphy can be used but requires thorough intraoperative evaluation to avoid missed nodes.
• Accurate sentinel node identification is critical for effective auricular melanoma staging and treatment.