• Cross section of a lymph node with extensive
replacement by metastatic melanoma.
• This lymph node is significantly enlarged and shows
replacement of the tissue by dark black
• Pigment production in this case is diagnostic of the
metastatic lesion, namely a metastatic melanoma.
• However, some melanomas may not produce melanin pigment
in the the primary site and/or the metastatic site.
• This sometimes creates a diagnostic dilemma.
|Metastatic malignancy in a lymph node|
•Secondary to malignancies elsewhere.
•Most common in carcinoma or as systemic involvement with lymphoma.
•Rare in sarcomas.
•Tumors invade lymphatics and spread to the local draining lymph node.
•Here, colonization occurs first underneath the capsule in the marginal sinus.
•Subsequently, the entire lymph node may be involved.
•The presence of metastatic deposits in draining lymph nodes
generally worsens the prognosis.
•In some malignancies, particularly those of internal
viscera, lymph node metastases may be the first
indication of a tumor.
|General Gross Description|
•Grossly, the lymph node may be of normal size or
•Depending upon the rate of growth of the tumor, there
may be necrosis, cystic change or hemorrhage.
•In extreme cases, cross section may reveal a completely or partially necrotic node, with the center appearing as a white pus-like material.
|General Micro Description|
•Microscopically, the tumor may be seen initially as
small deposits of tumor resembling the primary tumor
in the marginal sinus.
•Subsequently, deposits may be seen in the medullary
region of the lymph node.
•In extreme cases, the entire lymph node may be replaced
by tumor, leaving behind very little normal lymphoid
•Significant areas of necrosis, hemorrhage and liquefaction degeneration may be seen.
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 297.