The term "animal-type melanoma" appeared for the first time in 1999 in an article by Crowson et al. [11] in which six examples of melanomas that produced amounts extraordinary of pigment were reported on (see note in section I).

In their Table 1, the authors added 3 cases of their own to the 6 cases already recorded by Levene (1979), [7] Tuthill (1982), [8] and Pathy (1993), [9] thereby placing under the rubric of "animal-type melanoma" what had been published as pilar neurocristic hamartoma, melanoma arising in a blue nevus, and melanoma developing in dermal melanosis. Their study did not include, or even mention, the lesions described by Pearson et al. as cutaneous malignant melanotic neurocristic tumor.

The photographs presented by the coworkers, all of them taken at medium or high power magnification, do not allow for assessment adequate of the silhouette of the lesions; in fact, it is not possible to come to a decision about diagnosis with precision based on those images. Analysis of silhouette is essential because that pattern architectural reflects the behavior biologic of a particular proliferation.

Some lesions reported on by the coworkers certainly were malignant because patients bearing them developed metastases, some of them even dying from the effects of those missiles neoplastic. Other lesions, however, may have been benign. That the authors were unsure of the nature authentic of some of the neoplasms is apparent from the fact that they included in their differential diagnosis histopathologic the pigmented spindle-cell nevus of Reed which, by criteria architectural and cytopathologic, is diametric to melanoma, being the nevus stereotypical that it is.

Although melanoma that had undergone regression also was a consideration in the differential diagnosis forged by Crowson, Magro, and Mihm, they rejected that possibility out of hand and for this reason: "[in regressed melanoma] the nuclei are not atypical, but are small and round or reniform with small blue nucleoli." [11]

On the contrary, a melanoma that has undergone regression complete cannot exhibit nuclear atypia because there are no abnormal melanocytes that are residual; all have been destroyed by the effects on them of chemicals released from lymphocytes. And in a melanoma that has undergone regression partially or focally, the abnormal melanocytes yet undestroyed vary as greatly in appearance as do ones in a melanoma devoid of signs of regression, they being "atypical" and not "small and round or reniform with small blue nucleoli." In a melanoma that has regressed completely, as well as in one that has regressed in loci discrete, the cells residual are melanophages, not melanocytes.

"Animal-type" melanoma was so named by Crowson, Magro, and Mihm because of what they perceived to be its resemblance to equine melanotic disease, but the latter condition was said by Levene not to be associated with atypia cytopathologic except in cases deemed to be malignant overtly—and then it tends to be pigmented poorly! [4,7]

In reality, the only attribute of the lesions presented by Crowson et al. that seems to be similar to that of equine melanotic disease is prominent pigmentation, and it is far from compelling that this single feature justifies a new designation. Instead of coining new terms, it would be much more useful to construct criteria that enable a morphologist to distinguish between lesions benign and malignant. Pigmentation, no matter how scant or plentiful, in itself is irrelevant to the achievement of that desideratum; nevi sometimes are black, e.g., Reed's, and melanomas sometimes are red, they then often being misdiagnosed as "pyogenic granuloma."

The concluding remark by Crowson and collaborators is revealing: "Only long-term follow-up will determine whether lesions of "animal-type" melanoma should be further regarded as being of high or low risk for aggressive biologic behaviour. In those patients reported herein, in whom the cytomorphology was bland, there is no current evidence of a malignant behavior, whereas in those manifesting malignant nuclear features, one developed intracutaneous metastates (sic), one developed a regional lymph node metastasis but is still alive, and one died of lethal dissemination." [11]

Those two sentences might be more intelligible had they been phrased differently. This is what the authors might have said, plain and simple: "We do not know what, exactly, we are reporting on here. Some neoplasms surely were malignant (i.e., melanomas) because they metastasized and caused death, and some even may have been benign. Perhaps subsequent behavior biologic will resolve the issue of the character authentic of the ones that now seem to be benign. We must wait and see! In time, we may learn the answer, and if we do we certainly will share it with colleagues." Long-term follow-up, however, is not the method morphologists employ for diagnosis; they apply criteria morphologic, presumably repeatable and reliable and based on proven behavior biologic consistent, as the only route direct to diagnosis. Crowson et al. failed to set forth criteria histopathologic that permit a diagnosis of "animal-type melanoma" to be rendered with any degree of confidence. In fact, on completion of their article captioned, "Malignant melanoma with prominent pigment synthesis: 'Animal type' melanoma—A clinical and histological study of six cases with a consideration of other melanocytic neoplasms with prominent pigment synthesis," a reader diligent, dogged, and discerning has not the faintest idea of what, precisely, is an animal-type melanoma. That state unhappy, however, is not restricted to the subject of animal-type melanoma, equine melanotic disease, pilar neurocristic hamartoma, and cutaneous malignant melanotic neurocristic tumor, but to dysplastic nevus, dysplastic nevus syndrome, borderline melanoma, minimal deviation melanoma, nevoid melanoma, MELTUMP, SAMPUS, etc., etc., etc. All of it is "smoke and mirrors."

And last, in closing, to crown this masterpiece of confabulation, the authors made this statement enigmatic: "Furthermore, "animal-type" melanoma lacks histological features predictive of more aggressive behavior, namely high mitotic rates, regression, vascular invasion or ulceration." [11] High mitotic rates and ulceration are not indicative of more aggressive behavior of a proliferation of melanocytes, as evidenced convincingly by a Spitz's nevus that develops in a child, it often exhibiting numerous mitotic figures (one or more of which may be aberrant) and, at times, being ulcerated secondary to trauma external. Parenthetically, "more aggressive" than what?

In summary, we think some of the neoplasms presented by Crowson et al. were melanomas, some of those possibly arising in a congenital nevus of the type known as "blue." whereas others likely were nevi. To group them, melanomas and nevi, together under a single heading, improbable at that, of "animal-type melanoma" not only covers up ignorance, but it does a disservice monumental to colleagues and, through them, to patients.