Data is lacking on the dermoscopic features of mycosis fungoides (MF), the most common type of primary cutaneous T-cell lymphoma which has numerous clinical variants. A retrospective observational study published in the Journal of the European Academy of Dermatology and Venereology showed that dermoscopy provides a more precise characterization of classic MF, allowing more accurate disease staging.

Investigators enrolled patients with classic, folliculotropic, erythrodermic and poikilodermatous MF in the study. They performed standardized evaluations of dermoscopic pictures of the MF variants, and comparative analyses and dermascopic-pathological correlation assessments of different stages of classic MF.

There were 118 patients included: 75 with classic MF, 28 with folliculotropic MF, 9 with erythrodermic MF, and 8 with poikilodermatous MF. The mean age was 60.1 years, 68 patients were men.


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Investigators found that linear vessels (P =.009), linear-curved vessels (P =.013), and white scales in skin furrows (P =.003) were significantly associated with patch-stage MF compared with plaque and tumoral stage. Clustered dotted vessels were the only characteristic associated with plaque-stage MF (P =.001), and peripheral linear vessels with branches (P =.001), ulceration (P =.004) and red globules separated by white lines (P =.029) were associated with tumor-stage MF. Patchy-white scales were significantly more common in patches and plaques compared with tumors (P =.017), whereas focal bright white structureless areas were associated with both plaque and tumor stages (P =.009).

Dermoscopic-pathological correlation analysis found that vessels corresponded to dilated vascular structures in the dermis, orange structureless areas corresponded to either dermal hemosiderin (patch-plaque stage) or dense cellular infiltration (tumors), bright white lines/structureless areas corresponded to dermal fibrosis, and ulceration corresponded to loss of epidermis.

The main dermoscopic findings for folliculotropic MF were lack of hairs, dilated follicles, and follicular plugs. Main characteristics of erythrodermic MF were linear/dotted vessels, patchy white scales, and focal orange structureless areas. Poikilodermatous MF was mainly characterized by focal white and brown structureless areas, white patchy scales, and brown reticular lines.

The study was limited by its retrospective design, dermoscopic variability according to different anatomical areas was not assessed, and no control patients were included in the analysis.

The study authors emphasized the need to consider dermoscopic features “as an additional piece of the diagnostic puzzle,” making clinical decisions based on “the ‘2-step’ rule [clinical differential diagnosis followed by dermoscopic examination].”

Reference

Errichetti E, Apalla Z, Geller S, et al. Dermoscopic spectrum of mycosis fungoides: a retrospective observational study by the International Dermoscopy Society. J Eur Acad Dermatol Venereol. Published online March 14, 2022. doi:10.1111/jdv.18078