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Tautologies:
If we accept Ackerman’s statement (and it is difficult to accept without some dissection), then it becomes a portion of a system of logic in which “truths” are relative to basic definitions of the logic. The authors’ conclusion (Am J Surg Pathol 22:47, 2002), that a positive lymph node “can be assumed as evidence for malignant potential,” then can be characterized as tautologous. A truth table with truth functions and values will have been structured; the truth table is tautologous. In this sense, tautology and logic can be a play on words (actually, I have no idea what a truth table, truth functions, and truth values might be, or why they might qualify as tautologous).
What we do in pathology is in the nature of systems of logic with many defined values; these systems of logic constitute a language which is defined by truth functions and truth values. In the Spitz category, truth functions might be those images which tend to establish distinctions between “Spitz nevus” and “spitzoid melanoma” (when in fact, the distinctions are arbitrary and relative). Truth values might be the relative importance of respective truth functions in establishing distinctions [one of Barnhill’s (+) and (-) charts]. In my approach to MDM (nevoid melanomas), the emergence of a typical vertical growth pattern is a strong truth function. For many dermatopathologists great efforts have been expended in avoiding the designation, “vertical growth;” for these observers, there apparently is an inability to impose 3 dimensions on 2 dimensional histologic sections. The emphasis on a typical vertical growth pattern has not registered on the many pathologists who, wringing their hands, bemoan the lack of truth functions; in the reproductions of images, that have been provided by these wailers, typical vertical growth patterns abound. The intent of Barnhill’s assessment of some contributions as being tautologies is uncertain. I suppose he makes reference to what he considers to be needless repetitions. By the simple use of an uncommon word, was it his intent to discredit previous attempts to characterize the nature of “Spitz” variants? To denigrate studies in which material has been evaluated in retrospective fashion, makes a victim of the history and utility of pathology. It seems to me that Barnhill’s use of the word, tautology, is a sophism (and the authors [Am J Surg Pathol 26: 47,2002] apparently have bought it). How will Barnhill’s future offerings of solutions for the problematic category of “Spitz lesions”avoid being a tautology?
In the practice of pathology, a pathologist becomes a store of virtual images (truth functions). In structuring his store, he will have attempted to assign values (truth values) to these images. His ability to integrate functions and values will have an impact on his interpretations (the latter, I suppose, might be characterized as representing a truth table). His interpretation, in turn, will have led to a diagnosis (at this stage, logic has come into play). Classically, diagnoses in pathlolgy have had a digital quality; they are either a 1 or a 0. Currently, the need for a continuum in the interpretation of neoplasia has been emphasized and promoted.
The basis of pathology has been retrospective studies. In this approach, we re-examine cases which we have previously interpreted. The results of such an approach can be characterized as having the qualities of tautologies. In our histologic examinations, relevant truth functions are searched out, and then assigned truth values. Barnhill would criticize this approach?
A.B. Ackerman’s proposes that logic is the instrument by which the nature of metastasizing “Spitz” variants will be exposed. His logic is digital; 1 or 0; benign or malignant; nevus or melanoma. He has even extended this simple approach to other neoplasms and lesions: carcinoma but no category for actinic keratosis; and lymphoma but no category of primary follicular mucinosis. In this system of “logic,” there are no keratoacanthomas, only carcinomas; similarly, there are no proliferating pilar tumors, only carcinomas. This is logic in which definitions are individualistic; in his set, “truth values” are simplistic; this approach might even be characterized as having an anti-medico-legal application. In Ackerman’s logic, one example of a truth value is the opinion that there is only “one” melanoma; in this system of logic, if a melanocytic lesion metastasizes to a lymph node, then by the assigned “truth values” that lesion is the “one” melanoma.
How to handle different truth values? Where in the “Spitz” controversy might we search for relief. The appropriate area might be an examination of the designation, “Spitz nevus.” I have not searched out the source of this designation (I hope I was not the source). I would emphasize that, of the components of the designation, it is “nevus” that is offensive. Helwig proposed the designation, spindle cell “nevus.” Lauren Ackerman proposed the designation, spindle and epithelioid cell “nevus.” As late as 1963, Arthur Allen was still referring to this category as juvenile “melanoma,” but Allen’s contributions to dermatopathology have been called into question by A. B. Ackerman.
Spitz “nevus” is unlike classic nevocytic nevus. It does not behave like a common nevus; it does not look like a common nevus. It can appear de novo at any age. To the best of my knowledge, it is a locally progressive neoplasm; it lacks the slow growth of a nevus. A potential to mature and differentiate (i.e., neurotization) is not a feature; maturation in this category is a measure of the width of fascicles and the size of cells at various levels (an evaluation of physical characteristics). If left undisturbed, the Spitz lesion enlarges; large lesions tend to be more atypical than small lesions; this observation may be cited as evidence of neoplastic progression. In spite of Ackerman’s papal-like interdictions, the melanocytic system of neoplasia remains complicated; nature has not heeded the interdictions. LMM is a distinctive variant; ALM is a distinctive variant; desmoplastic and neurotropic melanomas are distinctive. The latter two variants imprint their own unique clinical characteristics.
The concept of MDM gives recognition to metastasizing lesions with deceptive histologic features. These features can be compared to those of variant “nevi;” observers, who don’t wish to be tainted with the accusation that they actually support the concept of MDM, avoid the stigmata by assigning such lesions to the category of “nevoid” melanoma, and by then certifying that they are uncertain as to the nature of MDM.
Why is it so difficult to establish truth values for truth functions in the Spitz category? The difficulty resides in large part in the designation, Spitz “nevus” (I make this evaluation with the realization that a critic will merely propose that the common nevus is a neoplasm - I readily grant such a concession with the stipulation that the habits of a common nevus are of the type characterized as nevoid). The habits of lesions in the Spitz category are neoplastic not nevoid. They find expression in a range of histologic and cytologic variations that can be better compared to the range of variations encountered in the common dysplasia-melanoma sequence.
The atypia of “recurrent Spitz nevus” is not an expression of a reactive change in a biopsy site; it is evidence of a neoplastic progression. In similar fashion, nodal metastases in association with a Spitz lesion, are generally more atypical than the patterns in the primary lesion. In part, this may reflect an organizing influence in the dermis which is lacking in lymph nodes; in part, it may be evidence of dedifferentiation (neoplastic progression) in the nodal deposits.
In our endeavors to understand classic Spitz lesions, truth functions and truth values have evolved, but they have been lost or muddled in an attempt to digitize biologic phenomena; an inappropriate name (with the assigned biologic implications of a specific system of logic) has been chosen; in the act, the implications of certain biologic phenomena also are encompassed. In our attempts to come to terms with the unexpected in the Spitz “nevus” category, we keep trying to accommodate a neoplasm using the logic for a nevus; in the act we encounter truth functions and values that obsfucate our efforts. As a neoplasm, the lesion remains unique. If it is so delicately prone to progression, yet so unpredictable in biologic expressions, it is a most unusual tumor. I would suggest that we cease to speak of the variants as either benign or malignant. Instead, this category may be a most striking example of intermediate neoplasia - a tumor in the borderland from inception. If we presist in defining a certain stage of the neoplastic options as a “Spitz nevus,” indecision will continue to be our lot. I have no problem with a return to the designation of “juvenile melanoma” (hooray for Sophie Spitz). In this acceptance, juvenile melanoma and MDM of the Spitz type are one and the same.
While we are on the subject of neoplasia as distinct from nevus, the “halo nevus” deserves comment. Halo phenomena are related to the expression of “self-antigens.” This expression can be characterized as near-neoplasia. In concert with these expressions, cytologic deviations are common; they include nuclear hyperchromatism, mitotic activity, and cytologic deviations. In addition, regressive phenomena are the expression of the effects of aggressive lymphocytes. Halo nevus is halo melanocytoma of near-neoplasia (intermediate neoplasia). It has its own relationship to progressive neoplasia in the intermediate category. Progressions may be mostly dermal. Some examples are associated with patterns of melanocytic dysplasia at the dermal-epidermal interface; in variants of the latter type, progressions may lead to something which somewhat resembles common melanoma of the common dysplasia-melanoma sequence. More often progressions lead to patterns that have a better defined relationship to nevoid melanoma in nevocyte-like patterns (a lesion easily misdiagnosed as a nevus).
If Spitz lesions and halo “nevi” are neoplasms, then what should we make of “Spitz nevus with halo nevus phenomena?” The combination is also neoplastic; such a lesion would be beyond the boundaries within which common nevi can be defined.
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