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RACS ASC 2024

Navigating Desmoplastic Melanoma: Diagnostic Dilemmas and Therapeutic Insights

Poster

Presentation Description

Institution: Peter MacCallum Cancer Centre, Melbourne - Victoria, Australia

CASE: An 88-year-old female presented with a non-pigmented nodular lesion on her left earlobe, which was subsequently diagnosed as pT4a Desmoplastic Melanoma (DM) with a Breslow Thickness (BT) of 4.5mm. International guidelines typically recommend sentinel lymph node biopsy (SLNB) for BT >4mm, but a systematic review by Hodson et al. found sentinel node metastasis rates below the 5% threshold for desmoplastic melanoma, calling the role of SLNB into question. With a calculated 1% risk of sentinel node metastasis in this case, the consensus of the Melanoma Multidisciplinary Meeting was for 2cm Wide Local Excision (WLE) without SLNB or pre-operative positron emission computed tomography (PET-CT). DISCUSSION: Desmoplastic Melanoma (DM) is a rare melanoma subtype, often presenting as non-pigmented firm nodules, making it challenging to diagnose. DM is typically thick at diagnosis, with a BT ≥4mm. DM is associated with a higher local recurrence rate, with meta-analysis suggesting a 21% recurrence rate after WLE. Treatment includes excision with BT-specific margins and consideration of radiotherapy in select cases. Immunotherapy with anti-PD1 agents shows promise in advanced DM cases. This case underscores the atypical presentation and lower metastatic potential of DM, emphasizing the need for specialist pathology review and multidisciplinary discussions to tailor individualized surgical and adjuvant treatment strategies. CONCLUSION: Desmoplastic Melanoma challenges the standard treatment algorithm for Malignant Melanoma, warranting further research and clinical consideration. References: Hodson M, Feustel P, Davis L. Sentinel lymph node biopsy in desmoplastic melanoma – the percent desmoplastic component matters: A systematic review.

Speakers

Authors

Authors

Dr Nupur Shukla - , Dr Hao Zhang - , Dr Sam Hamilton - , Dr Christopher Angel - , Dr Benjamin Baker -