Sometimes a malignant melanoma may spontaneously regress. If the entire lesion disappears then it is complete regression. If only a portion does then it is partial regression.
Proposed mechanism: cytotoxic immune response to tumor antigens
Regression can be seen both grossly and microscopically.
The size of the melanoma may decrease and sometimes disappear. With partial regression the change is limited to a portion of the lesion.
Color changes associated with regression may range from:
(1) white from loss of pigment
(2) red from inflammation and/or increased vascularity
(3) blue from dermal fibrosis and pigmentary incontinence
Microscopically there may be:
(1) fibrosis
(2) lymphocytic infiltrate
(3) tumor involution
Histologic regression can be identified more easily in an immunoperoxidase stain for melanocytic marker.
Regression most often is partial, and often there is another area that is progressing. A skin lesion may totally regress but metastases may not.
To read more or access our algorithms and calculators, please log in or register.
