Nevus Cells within Lymph Nodes: Possible Metastases from a Benign intradermal Nevus

Abstract

Two axillary lymph nodes from a patient who underwent modified radical mastectomy for carcinoma of the breast showed benign nevus cells in the fibrous capsule and within afferent lymphatics. Subsequently, an intradermal nevus from the area of drainage of the axillary lymph nodes was excised, which showed groups of nevus cells lying within small lymphatic channels. It is postulated that the nevus cells in the lymph node capsule could represent benign metastases from the intradermal nevus.

Immunostaining for the tumour suppressor gene p16 product is a useful marker to differentiate melanoma metastasis from lymph-node nevus

“…We, therefore, assume these cells to be melanocytes. This finding adds support to the hypothesis of the embolic origin of lymph-node nevi [2], which was put forward in previous reports in which melanocytes have been demonstrated to occur in the sinus of lymph nodes [20]. A recent study [6] has noted a strong association between nodal and cutaneous nevi.…”

“…However, this criterion proves not to be entirely reliable, as melanoma metastases are sometimes confined to the lymphatic space adjacent to the lymph-node capsule (Fig. 2) and nodal nevi may show parenchymal involvement [20]. The demonstration of the expression of HMB 45 may be helpful, although not entirely reliable, as a loss of HMB 45 expression is reported in at least 20% of melanoma metastases [4].…”

Nevus Cell Aggregates in Lymph Nodes

“…5 (5) Nevus cell clusters are found within cutaneous lymphatics 6,22,24 and in afferent lymphatics of lymph nodes, which are not known to have a role in embryonic migration of neural crest-derived cells. 22 (6) Melanocytes "arrested" in their migration through the dermis are bipolar, whereas, in most cases, nevus cells in lymph nodes have the oval or cuboidal contours encountered in conventional cutaneous melanocytic nevi. 9 A number of counterarguments could be made against the arrested migration theory.…”

“…Despite the concurrent timing of neural crest cell migration and lymphatic system development, lymphatics have no known role in this migration process. 21,22 An apparent lack of cutaneous nevi in the catchment areas of involved nodes is difficult to prove, since nevus cells can be found incidentally in skin biopsy specimens when no obvious lesion is noted clinically. The deep dermal extension of congenital nevi and resulting increased likelihood of lymphatic involvement also could explain the propensity of these nevi for nodal involvement.…”

Congenital Plantar Melanocytic Nevus with Satellite Lesions

“…Nevus cells are at times seen within the lymphatic vessels [5 -8 ] as well as in blood vessels [6][7][8] in congenital melano cytic nevi. Once the nevus cells enter into the lymphatics, they transitionally spread and finally reach the regional lymph nodes [9][10][11][12][13], Therefore, it is likely that in the sat«. '-lite lesions in our case some nevus cells might have been trapped in the skin after spread through the lymphatic vessels in a fashion similar to that in in transit metastasis fre quently observed in malignant melanoma [4].…”