Nodal blue nevi. A study of three cases.

Three cases of blue nevi associated within lymph nodes were identified. These nodal blue nevi were all incidentally discovered in relation to axillary lymph nodes removed as part of modified radical mastectomy procedures for carcinoma of the breast. Only one lymph node from each axillary dissection contained the lesion. In one case, gross examination revealed black streaks in the capsule of the lymph node, providing the first reported macroscopic illustration of the blue nevus within the capsule of a lymph node. The lesions each occupied small portions of the lymph node capsules, with penetration into perinodal fibroadipose tissue in two cases and extension along intranodal fibrous trabeculae in the third case. Histologically, heavily pigmented dendritic and bipolar nevus cells were admixed with melanophages. Ultrastructural examination of one case documented the presence of mature melanosomes and possible basement membrane material. None of the patients had notable skin lesions and all were free of disease at last follow-up. Nodal blue nevi are probably an unusual variant of the nevus aggregate associated with lymph nodes. These lesions limited to the nodal capsule and supporting stroma should not be mistaken for malignant melanoma.