Dermatopathology

Melanoma with Regression

Malignant melanoma, superficial spreading, Clark level IV. An incipient vertical growth phase is present. There is extensive regressive fibrosis as well.

Click images to begin the slideshow

Slide 1: 70 year old man with an upper arm lesion.

Slide 2: This excision specimen shows a highly atypical melanocytic lesion characterized by a confluent growth of severely atypical epithelioid melanocytes along the dermal-epidermal junction. There is significant and rather striking pagetosis of this abnormal melanocytic population. The epidermis is notably attenuated. Overall the findings are compatible with a fully evolved melanoma in situ.

Slide 3: In addition, however, there are areas of invasive melanoma as well characterized by singly disposed malignant epithelioid melanocytes that percolate through a fibrotic and inflamed dermis. The invasive melanoma extends for a Clark level III. However, the regressive stromal changes exceed the depth of tumor invasion.

Slide 4: The elastic tissue stain shows elastolysis within the zone of regressive fibrosis showing a very fine condensation of delicate elastic fibers separating the zone of regression from the uninvolved reticular dermis.

Slide 5: On the Ki-67/Melan-A preparation there is extensive pagetosis. A number of the pagetoid cells are stained by Melan-A and Ki67. The Melan-A (cytoplasmic-red) preparation also highlights the invasive melanoma component.