What is the primary location of melanoma that would metastasize to cervical (neck) and elbow lymph nodes?

From the Guidelines

Melanoma on the upper extremity, particularly the arm or hand, would most likely spread to both neck and elbow lymph nodes. This pattern occurs because melanoma typically spreads through the lymphatic system following predictable drainage pathways, as outlined in the nccn guidelines® insights: melanoma: cutaneous, version 2.2021 1. The upper extremity has lymphatic vessels that drain primarily to the axillary (armpit) and epitrochlear (elbow) lymph nodes, but can also connect to cervical (neck) lymph nodes through collateral lymphatic channels. Some key points to consider include:

• The dual drainage pattern is particularly common with melanomas located on the upper outer arm or shoulder, where lymphatic watersheds exist.
• The metastatic spread follows the principle of sequential lymphatic drainage, where cancer cells travel through lymphatic vessels to the nearest lymph node basin first (sentinel nodes), then potentially to more distant nodal basins.
• Understanding these drainage patterns is crucial for proper staging and treatment planning, including sentinel lymph node biopsies which help determine the extent of spread and guide surgical management decisions, as noted in the guidelines 1. Key factors that influence the likelihood of metastasis to cervical and elbow lymph nodes include:
• The location of the primary melanoma on the upper extremity
• The presence of lymphatic watersheds, which can facilitate the spread of cancer cells to multiple lymph node basins
• The sequential nature of lymphatic drainage, which determines the order in which lymph node basins are involved.

From the Research

Primary Location of Melanoma

The primary location of melanoma that would metastasize to cervical (neck) and elbow lymph nodes can be determined by understanding the lymphatic drainage pathways.

• The study 2 found that lymphatic drainage pathways from the upper back and upper limb primaries can drain to triangular intermuscular space sentinel lymph nodes, and occasionally to node fields on the opposite side of the body.
• Another study 3 reported a case of primary cutaneous melanoma of the forearm with epitrochlear and axillary lymphadenopathy, highlighting the possibility of metastasis to the elbow lymph nodes from a forearm primary.
• The lymphatic drainage patterns and sentinel lymph node locations can vary, and knowledge of these patterns is essential for accurate staging and treatment of melanoma 2, 4, 5.

Lymphatic Drainage Pathways

The lymphatic drainage pathways for melanoma can be complex and unpredictable.

• The study 2 identified new pathways, including drainage to paraaortic and retroperitoneal sentinel lymph nodes from upper and lower back primaries.
• The study 3 emphasized the importance of searching for sentinel lymph nodes in the epitrochlear region, even though it is an uncommon location.
• Understanding these pathways is crucial for identifying the primary location of melanoma that would metastasize to cervical and elbow lymph nodes 2, 3.

Sentinel Lymph Node Biopsy

Sentinel lymph node biopsy is a crucial procedure for staging and treating melanoma.

• The study 5 highlighted the accuracy and low morbidity of lymphatic mapping and sentinel lymph node biopsy.
• The study 6 emphasized the ongoing value of sentinel lymph node biopsy in providing prognostic information and durable regional nodal disease control.
• Sentinel lymph node biopsy can help identify the primary location of melanoma that would metastasize to cervical and elbow lymph nodes, and guide treatment decisions 4, 5, 6.