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If the reader will go to chapter c29t3P3, there are additional clues as to the nature of a few of the lesions. The clues include histologic evidence of vascular invasion, and lymph node metastases.
Up to this point, I have not provided the reader with additional history or histologic clues which might influence his interpretation of the lesions. I intended the reader’s approach, up to this point, to be prospective, as if the responsibility for the interpretation of these lesions were his, and his alone. In this SECTION, as is often the case in actual practice, clinical observations and historical data are not available to aid in the elicitation of sets of virtual images. The observer is left with the real images, and with whatever virtual images he can dredge-up. In the captions for each case, a few histologic clues, which might an aid in eliciting sets of virtual images, are identified. The deficiency in regard to clinical and histologic data is partly intentional; in large part, it represents a compromise over which I have no recourse. I have discarded the relevant files for these cases. These are all medico-legal cases; claims were filed. On this basis, some of the lesions may have recurred locally, and the diagnosis for the recurrent material was “melanoma.” Some of the cases must have metastasized, either locally to regional nodes, or in disseminated patterns. The medico-legal claim of malpractice is the glue that unites all these cases. Why would I discard such valuable material? The reason comes under the heading of “putting things in order,” and for that I will not apologize. If, by chance, I had encountered the photographic material before the legal documents, I would have preserved some of the material (the material having to do with clinical course , patterns of metastasis, original histologic diagnosis, etc.). The sequence led to a unfortunate act, but the photographic material still is important. If my foolishness offends you, I apologize; I am an old man. In my approach, I will place emphasis on tools embodied in the concept of MDM. This collection of tools is almost uniquely mine; it is peculiar to my approach to pathology. It has been politicized to the point of having been discredited in the eyes of many practicing pathologists. In practice, if you employ the virtual images related to nevoid melanoma, you have endorsed the concept of MDM, despite protestations by others.
The lesion in case 1 is fasciculated; the tumor cells are spindle shaped; the stroma is edematous; perhaps, some observers might characterize some of the patterns as a raining down of fascicles. If these taxonomic clues elicit a set of virtual images, they are likely to have relevance with those commonly utilized in the interpretation of Spitz “nevus.” The lesion by histologic criteria clearly is not a “classic Spitz nevus.” It can be accommodated in the MDM category, and additionally qualified as a Spitz variant. It might even be classified as MDM of non-Spitz type. It might be characterized as MDM (ambiguous phenotype). Some observers might characterize the lesion as spitzoid melanoma but, in doing so, the assignment would become a very personalized choice. On the basis of cytologic features, it seems to be beyond the category of the variant “nevi.”
That emphasis, in the expositionof histologic features, has been placed, for all these cases, on vertical growth-like patterns should be obvious to the reader. For only one lesion was a vertical growth-like component lacking (case 3); in this lesion, patterns of regression were represented. Markers for host immune response (another characterization that has been vilified) are represented. The asymmetry of the area of regression might be cited as evidence against the possibility that the lesion is halo “nevus” late in its evolution. A diagnosis of melanoma is not possible from the available material, but the patterns are compatible with those that might be seen in an area in which a vertical growth component has undergone regression. The lesion qualifies as being of indeterminate malignant potential; the result of any attempt at prognostic evaluation would also have to be considered conservative. Additional sections might have been of interest.
The lesion in case 2 is a thin melanoma of SSM type. There are patterns of early (young) vertical growth. It is the vertical growth component that identifies the lesion as a process with a potential for metastasis, despite the thin vertical dimensions. To place emphasis primarily on the location of cells in the epidermis would lead the observer away from a pattern which biologically is most important. On the basis of thin vertical dimensions (less than 1 mm in vertical dimensions), the lesion qualifies as borderline melanocytic neoplasia of indeterminate malignant potential. The patterns of regression are lagniappe; they also identify the lesion as a process of indeterminate malignant potential; in the face of regression, any prognostic evaluations must be considered conservative.
The lesion in case 4 qualifies as MDM of pigmented spindle cell type (non-Spitz type). MDM of this type do metatasize, and may do so with greater frequency than with some of the other variants of MDM. If emphasis is placed on sets of virtual images having to do with the interpretation of Spitz variants, particularly Spitz “nevus,” then there may be sufficient congruity to lead an observer to the diagnosis of pigmented “Spitz nevus.” This would be a mistake. The nuclear characteristics, particularly the variations in nuclear outlines and staining, and solid nesting patterns (i.e., typical vertical growth) should be an aid in leading the observer to alternate sets of virtual images.
In the lesion of case 5, the cells are epithelioid and nesting patterns are deviant. The lesion focally has sclerosing qualities. The patterns are such that some observers might evoke images of “sclerosing Spitz nevus” to compare with the real images. The cytologic features and the nesting patterns are common in the setting of MDM.
The lesion in case 6 is another example of MDM of the pigmented spindle cell (non-Spitz) type. Again, an observer might evoke the bundle of virtual images having utility for the interpretation of “Spitz nevus,” and find sufficient congruence to lead him astray. The cytologic features are deviant.
The patterns in case 7 are deceptively nevoid. Atypical “nevus” and “nevoid” melanoma might be considered in the differential diagnosis. With the tools for the interpretation of MDM, the lesion qualifies as MDM of common nevus-like type. At the dermal-epidermal interface, the patterns are those of melanocytic dysplasia. These patterns, in combination with a minimal deviation vertical growth-like component, are sufficient to warrant classifying the lesion as MDM.
The lesion in case 8 is another spindle cell MDM of non-Spitz (pigmented spindle cell) type.
The lesion in case 9 is a pleomorphic pigmented spindle cell melanoma. It is high grade cytologically, and is associated with poor prognostic parameters such as size, necrosis, and ulceration. It was, however, included in this collection of cases.
The lesion in case 10 is a spindle cell MDM of non-Spitz type. It is large and somewhat aggressive in regard to patterns of infiltration. It likely has extended into the fat (level V pattern). It recurred locally. As I remember the history for this case, there were metastases.
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