GENERAL  INDEX

Fig. c3t3P1: “Spitz nevus” in classical patterns is represented. The epidermis is irregularly hyperplastic. There are areas of edema in the papillary dermis. The tumor is wedge-shaped with the base  abutting upon the epidermis. The apex extends to the deep margin of the biopsy. There is no evidence of lentiginous and junctional  spread in the epidermis away from the dermal component. There are minimal perivascular infiltrates of lymphoid cells in the dermis at the advancing margin of the tumor. The lesion is  symmetrical.

Fig. c3t3P2: In this classical “Spitz nevus,” fascicles of uniform, pale spindle cells rain down into the dermis. The epidermis is irregularly hyperplastic. The papillary dermis is widened and  edematous. Vessels of the edematous papillary dermis are ectatic.  The fascicles of neoplastic cells extend into the reticular dermis among collagen bundles. At the deep margin of this field, the  fascicles are thinner than those near the dermal-epidermal interface (“maturation”).

Note: If we evoke the terminology (as related to a special system of logic) of common melanoma rather than the logic pertaining to “nevus” for the patterns in this field, the  component in the reticular dermis would qualify as migrant vertical growth-like.

Fig. c3t3P4: Atypia has been accepted in the category of “Spitz  nevus;” the level of acceptance has compromised the utility of the concept, or raised questions regarding the accuracy of the related system of logic (a system in which attempts are made to accommodate  nevoid qualities). The atypia in this example is moderately severe. There is nuclear pleomorphism with variation in nuclear size and staining. Upward migration of both nests of cells and individual cells has also been accepted in the category. Even though this lesion is thin, it has migrated into the upper portion of the reticular dermis. At the advancing deep margin, individual neoplastic cells extend among the collagen bundles. Lymphoid infiltrates are mild. In the junctional component, there are scattered giant  cells.

Note: Commonly, dermatopathologists have accepted properties and patterns in the “Spitz nevus” category which, if evaluated using the logic pertaining to the common melanoma, have more in common with melanoma than “nevus.” Cytologic atypia and pleomorphism, upward migration of neoplastic cells in the epidermis, migrant vertical growth-like patterns are acceptable truth functions in one system of logic that has been promoted as having  relevance for the interpretations of “Spitz nevi.” Perhaps, much of the  controversy which currently is associated with a diagnosis of “Spitz nevus” is related to too great a reliance on a faulty system of logic. As a starter, the Spitz lesion might be transferred from the nevoid category to the category of intermediate melanocytic neoplasia (i.e., minimal deviation melanoma, Spitz type). In anticipation of the objections to this recommendation, the lesion might be characterized as juvenile melanoma; the implications essentially would be the same.

Fig. c3t3P5: In this example, the patterns at the advancing margin are “Spitz nevus-like,” but the cells are cytologically atypical. There is little evidence of maturation. The individual cells among the collagen bundles are rounded or polygonal in outline; this alteration in cytologic features may relate to the acquisition of  ameboid characteristics. The dermis is relatively free of  inflammation. In many examples, as in this example, the cells  migrating into the reticular dermis do not induce significant  alterations in the pattern of collagen bundles of the reticular  dermis. In some examples, the cells in the reticular dermis are  associated with a desmoplastic response in the dermis.

Fig. c3t3P6: This is a classic “Spitz nevus” pattern. The lesion is  distinguished by an inordinate number of giant cells. Papillary  dermal edema and vascular ectasia are prominent features. There is some degree of nuclear atypia and pleomorphism.