|LETTER TO EDITOR
|Year : 2018 | Volume
| Issue : 2 | Page : 135
Dermal melanophages: Is quantification necessary?
Rajiv S Joshi
Department of Dermatology, P. D. Hinduja Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||19-Dec-2018|
Dr. Rajiv S Joshi
Department of Dermatology, P. D. Hinduja Hospital, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Joshi RS. Dermal melanophages: Is quantification necessary?. Indian J Dermatopathol Diagn Dermatol 2018;5:135
We thank the authors for their interest in our paper and fully agree with them on the drawbacks of this study regarding validation of the scores which requires evaluation of interobserver variation and repeatability of scores by the same observer. These and other lacunae in this study have been mentioned by us in our study.
This has been the first study in extant literature to attempt a quantitative evaluation of melanophages seen in inflammatory diseases and to correlate the scores with the known pathomechanisms of inflammatory diseases to assess the significance of the presence of dermal melanophages.
By themselves, dermal melanophages are not diagnostic of any condition, but evaluation of them for number, extent, and distribution and morphological characteristics gives clues and credence to the histopathological diagnosis.
As this study has shown even clinically hypopigmented conditions like vitiligo show melanophages, albeit few in number. Also common conditions like psoriasis too show few melanophages that are often not mentioned in histopathological reports as they are considered insignificant and not important for the diagnosis.
Melanophages may also be seen in epidermal hypermelanotic conditions such as melasma and idiopathic eruptive macular pigmentation (IEMP), but their scores are always low unlike the high scores seen in dermal pigmentary conditions that follow interface dermatitides. This is important because, in the past, the presence of melanophages (without any quantification) has been used as a diagnostic criterion for IEMP, causing confusion in differentiating IEMP which is primarily an epidermal hypermelanotic condition and should not theoretically have melanophages, from true dermal melanoses such as lichen planus pigmentosus which is always replete with many melanophages.
Regarding the authors' query “Does quantitative assessment play a role in the diagnosis of inflammatory skin diseases,” we reiterate that surgical pathology and dermatopathology are subjective sciences where interpretation of morphological findings plays a role in the diagnosis and quantification of findings is neither desirable nor applicable in every case. However, in certain situations, an attempt at quantification does provide a guideline or support for interpretation of the findings to come to a final diagnosis. For example, tagging of lymphocytes as single units along the basal layer, the so-called toy soldier sign is commonly seen in patch-stage mycosis fungoides but may also be seen in several other conditions including vitiligo. Recommendations have been made that the presence of at least four lymphocytes is suggestive of patch-stage mycosis fungoides and most dermatopathologists aver with that figure. There is nothing sacrosanct about the number 4, it could have been 3 or 5, but it gives a guideline whenever one sees tagging of haloed lymphocytes within the basal layer and is considering a diagnosis of patch mycosis fungoides.
We hope that the findings and observations presented in this paper will stimulate prospective studies to assess and correlate dermal melanophages with clinical scores of pigmentation in hypermelanotic as well as hypomelanotic conditions for better understanding of those conditions as well as better management of patients.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Joshi RS. Description of a proposed simple semi objective histological scale for the assessment of dermal melanophages in inflammatory skin diseases. Indian J Dermatopathol Diagn Dermatol 2018;5:34-8. [Full text]
Joshi RS, Rohatgi S. Idiopathic eruptive macular pigmentation: A critical review of published literature and suggestions for revision of criteria for diagnosis. Indian J Dermatol Venereol Leprol 2015;81:576-80.
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