Exuberant nodal nevi: study of four cases with the focus on diagnostic pitfall of metastatic melanoma.

Nodal melanocytic nevi are benign proliferations found in lymph nodes. While they are typically localized, small proliferations within the lymph node capsule, occasionally they can show florid growth patterns, raising concern for metastatic melanoma. We report four unusual cases of exuberant nodal nevi with discussion of the morphologic and immunophenotypic features. In all four cases, the differential diagnosis included metastatic melanoma. We report these cases to highlight an important diagnostic pitfall that may occur when nodal nevomelanocytic proliferations show exuberant growth patterns.