FIGURE F15.1.1 • Photomicrograph of a malignant melanoma lesion in the early stage of radial growth phase. This section of the skin shows a layer of the epidermis containing atypical (hyperplasic) cells loaded with dark-brown pigment granules containing melanin. These cells represent atypical melanocytes that normally should reside in the stratum basale of the epidermis. At this stage of disease, these abnormal melanocytes migrate to the upper layers of the epidermis (melanocytic hyperplasia). There are scattered small nests of atypical cells in the dermis. Note the accumulation of lymphocytes in the superficial dermis. 320. Inset shows enlarged nest containing melanocytes with clearly visible processes containing melanin granules. 640. continued next page
FOLDER 15.1 Clinical Correlation: Cancers of Epidermal Origin (Cont.)
FIGURE F15.1.2 • Photograph of the skin with malignant melanoma during radial growth phase. In this individual, malignant melanoma is represented by the relatively flat, irregularly pigmented multicolor lesion. The largest nodule appears ebony black. It is adjacent to a slightly elevated region that is colored in shades from dark brown to light brown with two reddish smaller nodules in pink coloration. At this early stage, melanocytes grow in all directions, upward in the epidermis, downward into the dermis, and peripherally in the epidermis. (Reproduced from Storm CA, Elder DE. The Skin. In: Rubin R, Strayer DS (eds): Rubin’s Pathology: Clinicopathologic Foundations of Medicine, 5th ed. Baltimore: Lippincott Williams & Wilkins, 2008.)
The ABCD rule is helpful for remembering the signs and symptoms of melanoma (see Fig F15.1.2): shape of skin lesion•Border of the lesion is irregular•Color variations; melanomas usually have multiple colors of skin lesion; moles greater than 6 mm are more likely to be suspicious layer is relatively thin and includes the substance of the dermal papillae and dermal ridges. It contains blood vessels that serve but do not enter the epidermis. It also contains nerve processes that either terminate in the dermis or penetrate the basal lamina to enter the epithelial compartment. Because the blood vessels and sensory nerve endings are concentrated in this layer, they are particularly apparent in the dermal papillae.
 The reticular layer lies deep to the papillary layer. Although its thickness varies in different parts of the body, it is always considerably thicker and less cellular than the papillary layer. It is characterized by thick, irregular bundles of mostly type I collagen and by coarser elastic fibers.
The collagen and elastic fibers are not randomly oriented but form regular lines of tension in the skin called Langer’s lines. Skin incisions made  parallel to Langer’s lines heal with the least scarring.
In the skin of the areolae, penis, scrotum, and perineum, smooth muscle cells form a loose plexus in the deepest parts of the reticular layer. This arrangement accounts for the puckering of the skin at these sites, particularly in erectile organs.
Layers of adipose tissue, smooth muscle, and, in some sites, striated muscle may be found just beneath the reticular layer.
Deep to the reticular layer is a layer of adipose tissue, the panniculus adiposus, which varies in thickness. This layer
Surgery is a choice of treatment for localized malignant melanoma of the skin. A multidisciplinary approach is used for advanced malignant melanoma, including surgery combined with chemotherapy or immunotherapy with adjuvant treatment.
serves as a major energy storage site and also provides insulation. It is particularly thick in individuals who live in cold climates. This layer and its associated loose connective tissue constitute the hypodermis or subcutaneous fascia.