MINIMAL DEVIATION MELANOMA, HALO NEVUS VARIANT, FROM AN ADOLESCENT
LYMPH NODE METASTASIS OF UNCERTAIN BIOLOGIC POTENTIAL  PRESENT
These pictures are from the initial sections of a lesion from the area of the chin of a 15 year old male. There was nothing in these sections suggestive of the radial growth phase of a melanoma.
 
Scan power view. The tumor is relatively symmetrical, and there is a slight suggestion of nodularity, particularly in the superficial part of the tumor. The cell types are more randomly intermingled in the deep part of the tumor.
Low power view of a nodular focus. 
High power view of above. Atypical, large, epithelioid melanocytes, some of which are binucleate, are associated with a few lymphocytes. 

Nuclear pyknosis is present to varying degrees, and there is vacuolar change in some of the melanocytes. These findings are interpreted as evidence of  immunodestruction.
Low power view of an area where there is less of a nodular pattern.  Large epithelioid melanocytes are separated by lymphocytes, and such large cells are found in some halo nevi. These cells are universally more round than the epithelioid cells found in Spitz' nevi, and fascicles are not found in this case. 
High power view above.
High power view of another area (intermediate nodularity).  A focus such as this is disturbing in that this may represent the early formation of an expansile cluster or nodule of the the type characteristic of  a minimal deviation melanoma.

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