Fig. P15-41 (to the left): The biopsy specimen in 1993 was the product of an incisional biopsy. The lesion extends to the deep margin. Rounded nests of cells are irregularly distributed in the reticular dermis and are more closely clustered to the left of the center of the field. They sit in the dermis among collagen bundles and are associated with neither specialized stroma nor significan inflammatory infiltrates. Centrally and to the right of the center of the field, there are lentiginous and junctional components. The patterns in the lesion are fairly uniform at all levels. A single, compact, expansile nodule (i.e., typical vertical growth component is not a feature.).

Fig. P15-43 (to the left): Rete ridges are effaced. Atypical melanocyts are loosely and irregularly spaced in the basal layer of the epidermis (a lentiginous pattern in keeping with a variant of lentigo maligna). The cytologic atypia of the lentiginous component is moderate, even though the cellularity is mild. The lentiginous component involves a hair follicle to the right of the center of the field. The papillary dermis is not appreciably  widened and infiltrates of inflammatory cells are not a feature at any level in this field. The “rounded” nests of atypical, short, spindle cells sit in the reticualr dermis without inducing a significant stromal response.

Fig. P15-44 (to the left): The tumor cells are cytologically monotonous. They are intermediate in size and show a thin rim of pale acidophilic cytoplasm. Nuclei are rounded or ovoid and have delicate, uniformly distributed chromatin. Nucleoli are not prominent. Many of the nests of cells are outlined by thin, fibrous membranes. The intervening dermis shows solar elastosis. There is a

Fig. P15-45 (to the left): This field is representative of the recent (2000) biopsy specimen. Many of the features of the 1993 material are preserved. The lesion is mostly confined to the reticular dermis and spares the epidermis and the papillary dermis (it lacks a “primary  configuration”). It appears wedge-shaped but this, in large part, reflects the contour of the biopsy specimen rather than representing an accurate portrayal of the distribution of nests of cells in the dermis. The nests of cells sit in the reticular dermis and show more variability in size and outline than was seen in the 1993 material.