Diagrams 2
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Neoplasia

(in progression from dysplasia to vertial growth)

Fig.1, chapter 2, tier3

A plane intersects a cone; the plane represents the domain of evolving melanocytic dysplasias; beginning with the blue portion, there are four grade of dysplasia. The cone represents lesions showing patterns of vertical growth with diameter of the cone showing a relationship that is expressed in the progression of lesions in vertical growth. Note that there is no well-defined boundary in the early stages of evolution (a specific size of the vertical growth) that separates dysplasia from melanoma. Lesions measuring less than 1 mm in vertical growth qualify as borderline processes. Those in the range of 1 mm to 1.5 mm can be characterized as intermediate processes. The metastatic rate becomes more significant beyond 1.5 mm; such lesions qualify as “real” melanomas.

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Progression from dysplasia to vertical growth

(with representation of level IV patterns)

Fig. 2 chapter2, tier 3

The diagram depicts progression from dysplasia (the plane) to melanoma (with melanoma defined as a lesion in vertical growth as defined in the concept of MDM). Lesions in vertical growth are represented by the cone and for larger lesions showing typical vertical growth by the sphere. The red line depicts the boundary between a widened papillary dermis and the reticular dermis. The black dots in clusters are numerically significant; the more dots, the more extensive the invasion at level IV (invasion into, or beyond the reticular dermis. Four grade of dysplasia are depicted along the plane with the white portion to the extreme left representing so-called “melanoma-in-situ.

 

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Melanocytic Neoplastic Progressions

Fig. 3

    In the upper diagram, progression is linear from left to right. The domain from the left to the first vertically oriented boundary is representative of the “one dimensional” stage with lentiginous and junctional components and only occasional, widely and randomly spaced nests in the papillary dermis. In addition, the degree of atypia is mild to moderate. The domain from the first to the second boundary is that of a lesion showing the patterns in the epidermis of the “common final pathway” (i.e., WHC or Wally Clark’s cells). The restrictions on number and distribution of nests essentially are the same as in the first domain. The “common final pathway (CFP) is characterized by moderately severe to marked atypia and by the upper migration of atypical cells into the upper reaches of the epidermis. The next boundary defined the domain of lesions showing variant vertical growth in accretive patterns. Nests of cells are sequentially delivered from the epidermis into the dermis in stratified patterns (the red vector is vertically oriented with the arrow pointing down). The nests in the dermis are stratified as to degree of atypia and are loosely, but regularly, spaced in the widened papillary dermis to form a plaque. Beyond the last boundary, the nests of cells are generated in the dermis (interstitial growth) (universally directed vectors). The overall pattern is likely to be that of an expansile nodule in which the nests are closely aggregated and supported by a delicate, fibrous matrix. In this approach, there is an implication that vertical growth most commonly emerges in lesions which have progressed to a stage of marked atypia (i.e., Clark’s superficial spreading melanoma). On the other hand, the smaller diagram in the lover part of the field is an effort to give recognition to alternate pathways for the emergence of vertical growth. With the stipulation that there is congruence between the degree of atypia in the lower diagram and the corresponding segment of the upper diagram, some lesions enter vertical growth without progressing to the stage of marked atypia (i.e., the common final pathway). Such lesions are MDM. They may enter vertical growth in the “interval of susceptibility.” Lentigo maligna is the most common melanocytic dysplasia in which this alternate pathway is commonly manifested; many examples of lentigo maligna melanoma also qualify as MDM. Focal patterns of complete regression commonly are identified in lesions that otherwise qualify as dysplasias (i.e., level I & II lesions). In this approach to neoplasia, bulk and stages of progression are represented. There is no provision fo the representation of level IV phenomena. A borderland is appended.

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Patterns

(dysplasia and vertical growth)

Fig. 4

The variant and typical patterns in the dermal component of evolving melanocytic neoplasia are illustrated. At the top of the field, lentiginous and junctional patterns are represented. In addition, there is a solitary nest of neoplastic cells in a widened papillary dermis. The gradient for growht is perpendicular and directed into the dermis (i.e., cells “drop’ into the dermis). The limited patterns in the dermis qualify as “one dimensional.” In the middle diagram, the gradient is the same but the rate of the delivery of cells into the dermis exceeds the rate at which the newly arrived nests of cells are eradicated by the effects of the host immune response. The patterns in the demis are stratified as to degree of atypia with the most atypical population being the component near the dermal-epidermal interface. The pattern of growth is accretive. In the bottom diagram, the gradient is universal in symmetrically expansile pattern. The lesion is now dependent on the kinetics affecting the dermal population; the process is relatively independent of the phenomena at the   dermal-epidermal interface. In the dermal nidus, the newly formed nests are closely spaced and the stroma is delicate and vascularized.

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Dysplasia and Melanoma

Fig. 5

In this diagram, degrees of atypia are stratified vertically in yellow. Mild dysplasias (i.e., patterns correlated with degrees of atypia) are represented at the bottom and to the left of the diagram in green. Moderate to marked dysplasias are also represented in green. The dysplasias, other than the mild dysplasias, are in continuity with vertical growth components (in red); the two are sequentially related. More melanomas arise from marked dysplasias thant from moderate dysplasias. the domain of MDM (in that category in which degrees of dysplasia are emphasized as a factor of importance in the application of criteria) is sequenced with the moderate to moderately severe dysplasias.

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Diagrammatic Depiction of MDM

(variants of MDM in which “degrees of atypia” are a basic criterion)

Fig. 6

In this diagram, levels of invasion (Clark’s criteria as modified in concept of MDM) are vertically stratified. Along the horizonal axis, degrees of atypia are represented along the horizonal lines from mild on the left to marked on the right (i.e., the common final  pathway). Increasing bulk, as well as degree of invasiveness relate to level of invasion.Some melanomas may have their origin in a dysplasia in which degree of atypia is less than that of the common final pathway (i.e., MDM). Vertical growth is not simply a measure of depth of invasion. It is a pattern in which the close spacing of nests of cells to form a tumor is the basic requisite. The diagonal lines off the vertical axis define three boundaries along the bottom horizontal plane (level I & II). The domain to the left of the left-most diagonal line is that of the mild dysplasias. Between the left diagonal line and the middle line, the domain of the moderate dysplasias is represented. The domain between the middle line and the right-most diagonal line is that of the moderately severe dysplasias. Beyond the right line, the marked dysplasias are represented. The common final pathway (CFP) is represented in the domain of the marked dysplasias. In practice, the domain of the moderately severe dysplasias are oftenincluded in the domain of the common final pathway. The domains to the right of the left diagonal line, and above the bottom horizontal line are those of vertical growth components. Vertical growth, in association with lesser degrees of atypia than those of the common final pathway, defines this category of minimal deviation melanomas. There is no utility in characterizing patterns of lesions to the left of the left-most line as vertical growth and, then, accepting vertical growth as a marker for a melanoma. In this diagram, the reader might try to mentally represent a precise vertical dimension, such as the boundary for a borderland at 1 mm. The boundary cannot be represented in a manner that distinguishes between dysplasias (level I & II lesions) and melanomas (levels III and greater lesions). Levels of invasion are a measure of qualities that are independent of bulk. They have significance independently of the prognostic significance of bulk.

 

 

 

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