Special Anatomic Considerations

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • Epidemiology and Clinical Presentation of Plantar Melanoma:
    • Melanomas of the sole are predominantly acral lentiginous melanoma (ALM):
      • Which is the most common melanoma subtype in patients of African and Asian descent:
        • It is associated with a poorer prognosis due to frequent late-stage diagnosis
    • Acral lentiginous melanomas occur:
      • On the palms (palmar), soles (plantar), or beneath the nail beds (subungual):
        • Although not all palmar, plantar, and subungual melanomas are acral lentiginous melanomas
      • These melanomas account for only 2% to 8% of melanomas in white patients:
        • But for a substantially higher proportion of melanomas (35% to 60%) diagnosed in darker-skinned patients:
          • Their clinical extent at the primary site may be difficult to define, and scouting biopsies are sometimes employed to facilitate clinical assessment of the extent of disease
      • ALM on the sole often presents as an irregularly pigmented, asymmetric lesion with a parallel-ridge dermoscopic pattern:
        • Diagnosis requires a full-thickness excisional biopsy for histopathologic confirmation
  • Unique Anatomic and Surgical Challenges of the Sole:
    • The sole is characterized by thick, glabrous skin, minimal subcutaneous tissue, and a weight-bearing function:
      • All of which complicate surgical management
    • Achieving recommended excision margins:
      • Is often difficult due to the risk of exposing or injuring underlying structures and the challenge of primary closure
    • The need for wide excision can result in large defects that are difficult to reconstruct:
      • With a high risk of surgical complications such as delayed healing, infection, and impaired ambulation
    • These factors necessitate complex reconstructive approaches, including:
      • Local flaps or skin grafts, to restore both form and function and to preserve quality of life
  • Surgical Management and Margin Recommendations:
    • The standard of care is surgical excision with histologically negative margins
    • The American Academy of Dermatology and the National Comprehensive Cancer Network recommend margin width based on Breslow thickness:
      • 1 cm for melanomas ≤ 1 mm thick, and up to 2 cm for thicker lesions:
        • With excision to but not including the fascia
      • However, in the sole, these margins may need to be modified to preserve function and accommodate anatomic constraints:
        • Though sub-1-cm margins for invasive melanoma are generally not recommended unless absolutely necessary
      • Sentinel lymph node biopsy is indicated for invasive lesions (generally ≥ 0.8 mm or with other high-risk features) and should be performed prior to or at the time of wide excision
      • Closure of surgical defects often requires skin grafts or local flaps, such as medial plantar or sural neurocutaneous flaps, to achieve durable coverage and maintain ambulation
  • Special Considerations for Margin Assessment and Recurrence:
    • Melanomas of the sole, like other specialty sites, have higher rates of positive margins, local recurrence, and upstaging compared to trunk and proximal extremity melanomas
    • This is attributed to both the anatomic complexity and the frequent subclinical extension of ALM
    • Staged excision with comprehensive margin assessment (e.g., slow Mohs or complete circumferential peripheral and deep margin assessment [CCPDMA]) may be considered for melanoma in situ or thin ALM in anatomically constrained areas to maximize tissue conservation and ensure complete tumor removal, though prospective data are lacking
    • Mohs micrographic surgery is not recommended for invasive melanoma but may be selectively considered for melanoma in situ or minimally invasive lesions in specialty sites
  • Gaps in Evidence and Areas for Further Study:
    • There is a paucity of prospective, site-specific trials for plantar melanoma
    • Most recommendations are extrapolated from studies of melanomas at other sites, and further research is needed to define optimal surgical margins, reconstructive techniques, and long-term outcomes for melanomas of the sole
  • In summary:
    • The surgical management of melanomas on the sole requires careful consideration of the unique anatomic and functional challenges, with a focus on achieving negative margins, minimizing morbidity, and optimizing reconstruction to preserve ambulation and quality of life
    • Margin width should be tailored to tumor thickness and anatomic constraints, with a preference for standard margins when feasible, and the use of advanced margin assessment techniques in select cases
  • References:
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Published by Rodrigo Arrangoiz MS, MD, FACS, FSSO

My name is Rodrigo Arrangoiz I am a breast surgeon/ thyroid surgeon / parathyroid surgeon / head and neck surgeon / surgical oncologist that works at Center for Advanced Surgical Oncology in Miami, Florida. I was trained as a surgeon at Michigan State University from (2005 to 2010) where I was a chief resident in 2010. My surgical oncology and head and neck training was performed at the Fox Chase Cancer Center in Philadelphia from 2010 to 2012. At the same time I underwent a masters in science (Clinical research for health professionals) at the University of Drexel. Through the International Federation of Head and Neck Societies / Memorial Sloan Kettering Cancer Center I performed a two year head and neck surgery and oncology / endocrine fellowship that ended in 2016. Mi nombre es Rodrigo Arrangoiz, soy cirujano oncólogo / cirujano de tumores de cabeza y cuello / cirujano endocrino que trabaja Center for Advanced Surgical Oncology en Miami, Florida. Fui entrenado como cirujano en Michigan State University (2005 a 2010 ) donde fui jefe de residentes en 2010. Mi formación en oncología quirúrgica y e n tumores de cabeza y cuello se realizó en el Fox Chase Cancer Center en Filadelfia de 2010 a 2012. Al mismo tiempo, me sometí a una maestría en ciencias (investigación clínica para profesionales de la salud) en la Universidad de Drexel. A través de la Federación Internacional de Sociedades de Cabeza y Cuello / Memorial Sloan Kettering Cancer Center realicé una sub especialidad en cirugía de cabeza y cuello / cirugia endocrina de dos años que terminó en 2016.

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