From the Guidelines
No, a melanoma on the inner thigh would not typically affect the elbow, neck, or collarbone lymph nodes on the left side, but rather the inguinal and pelvic lymph nodes on the same side as the lesion. Lymphatic drainage follows predictable patterns, and melanomas generally spread first to the nearest lymph node basin 1. For the inner thigh, lymphatic fluid drains primarily to the superficial and deep inguinal lymph nodes, then potentially to the iliac and other pelvic lymph nodes. The absence of palpable pelvic lymph nodes doesn't rule out microscopic involvement, as deeper nodes cannot be felt on physical examination 1.
- Elbow, neck, and collarbone (axillary, cervical, and supraclavicular) lymph nodes drain the upper extremities, head, neck, and upper chest regions, not the lower extremities.
- If these distant nodes are enlarged in a patient with thigh melanoma, it could indicate either widespread metastatic disease that has progressed beyond regional nodes or an unrelated condition causing the lymphadenopathy.
- Sentinel lymph node biopsy is a valuable staging procedure for patients with melanoma who are at risk of clinically occult nodal metastases, and can guide treatment decisions 1.
From the Research
Lymph Node Involvement in Melanoma
- The provided studies do not directly address the question of lymph node involvement in melanoma on the inner thigh affecting the elbow, neck, and collar bone lymph nodes on the left side.
- However, it is known that melanoma can spread to lymph nodes, and the location of the primary tumor can influence the likelihood of lymph node involvement in specific areas [ 2, 3 ].
- The studies focus on the treatment and management of metastatic melanoma, including targeted therapy and immunotherapy [ 4, 5 ].
- One study discusses the use of FDG-PET imaging in predicting relapse in metastatic melanoma patients treated with immunotherapy, but it does not provide information on lymph node involvement [ 6 ].
Lymph Node Locations and Melanoma
- The lymph nodes in the pelvis are not typically the first site of lymph node involvement for melanomas located on the inner thigh.
- The lymph nodes in the groin area (inguinal lymph nodes) are more likely to be involved in melanomas located on the inner thigh.
- The involvement of lymph nodes in the elbow, neck, and collar bone area would be unusual for a melanoma located on the inner thigh, unless the cancer has spread to other parts of the body [ 2, 3 ].