Malignant melanoma primary in lymph node. The case of the missing link

Area of Science:

• Pathology
• Dermatology
• Oncology

Background:

• Lymph node melanoma is typically metastatic from a primary cutaneous or mucosal site.
• The origin of melanoma within lymph nodes without an apparent primary site is often unclear.
• Nevus cell aggregates and nodal blue nevi are known benign findings in lymph nodes.

Observation:

• A case of primary malignant melanoma was identified within an axillary lymph node.
• This melanoma appeared to evolve from coexisting nevus cell aggregates and blue nevi.
• The primary cutaneous or mucosal melanoma was not readily apparent.

Findings:

• The study documents a rare instance of primary lymph nodal malignant melanoma.
• The findings support the hypothesis that nevus cell aggregates and blue nevi can be progenitors of lymph nodal melanoma.
• The coexistence of these precursor lesions suggests a common origin from neural crest cells.

Implications:

• This case expands the understanding of melanoma origins and metastatic pathways.
• It highlights the importance of considering in-situ or occult primary lesions.
• Further research into neural crest cell migration and melanoma development is warranted.