minimal deviation melanoma, halo nevus type, followup

MINIMAL DEVIATION MELANOMA, HALO NEVUS TYPE, FOLLOWUP

The last set of sections were sent to Richard J. Reed, M.D. for his opinion. His diagnosis was: 'Minimal deviation melanoma of halo nevus type (dermal variant), borderline melanocytic neoplasia of indeterminate malignant potential, typical vertical growth, 0.78 mm. in vertical dimension'.

Sentinel lymph nodes were removed, and one of the six lymph nodes contained clusters of cells having the features of metastatic melanoma. Another node contained a few tiny clusters of S-100 positive cells (not illustrated) that were not demonstrated in the H&E stained sections. Following this, a cervical lymph node dissection was done, but no other positive nodes were found.

Low power view of the positive lymph node. The deposits (arrows) are in the peripheral parenchyma and not in the capsule or internal trabecula. This distribution is more characteristic of metastatic melanoma rather than of nodal nevus^{ref 1}.

Immunoperoxidase preparation of the above for S-100.

High power view of the immunoperxidase preparation. One of the cells (arrow) is much larger than the others. This is the only cell that resembled the large, epithelioid cells of the primary skin lesion.

High power view from this lymph node. There is a cell (arrow) that was interpreted to be in mitosis by one observer, but I had reservations about calling this a mitosis. Such a disparity in interpretation may be partly responsible for the lack of reproducibility of mitotic rates between pathologists when examining the same slide of a melanoma. The cytology of the cells is benign.

Low power view of a deeper section from this lymph node.

High power view of above. Minimal cytologic atypia is present.

Click on DISCUSSION for more information.
or
Click on your browser's 'Back' button to return to the previous page.

	Low power view of the positive lymph node. The deposits (arrows) are in the peripheral parenchyma and not in the capsule or internal trabecula. This distribution is more characteristic of metastatic melanoma rather than of nodal nevus^{ref 1}.
	Immunoperoxidase preparation of the above for S-100.
	High power view of the immunoperxidase preparation. One of the cells (arrow) is much larger than the others. This is the only cell that resembled the large, epithelioid cells of the primary skin lesion.
	High power view from this lymph node. There is a cell (arrow) that was interpreted to be in mitosis by one observer, but I had reservations about calling this a mitosis. Such a disparity in interpretation may be partly responsible for the lack of reproducibility of mitotic rates between pathologists when examining the same slide of a melanoma. The cytology of the cells is benign.
	Low power view of a deeper section from this lymph node.
	High power view of above. Minimal cytologic atypia is present.