Shany Sherman, Noa Kremer, Adam Dalal, Efrat Solomon-Cohen, Einav Berkovich, Yehonatan Noyman, Maya Ben-Lassan, Assi Levi, Lev Pavlovsky, Hadas Prag Naveh, Emmilia Hodak, Iris Amitay-Laish
DOI: 10.2340/00015555-3704

Patients with mycosis fungoides (MF) are thought to be at increased risk of melanoma. However, studies addressing surveillance-bias and treatments as a possible confounder are lacking. This retrospective study compared the prevalence and risk of melanoma between 982 patients with MF, and 3,165 patients with psoriasis attending tertiary cutaneous-lymphoma/psoriasis clinics during 2009 to 2018. Melanoma was diagnosed in 47 patients with MF (4.8%; 43 early-stage) and in 23 patients with psoriasis (0.7%) (odds ratio 6.6, p < 0.0001). In 60% of patients, MF/psoriasis preceded melanoma diagnosis. Hazard ratio (HR) for a subsequent melanoma in MF vs psoriasis was 6.3 (95% confidence interval (95% CI) 3.4–11.7, p < 0.0001). Compared with the general population, melanoma standardized incidence ratios were 17.5 in patients with MF (95% CI 11.0–23.9, p < 0.0001), and 2.2 (95% CI 0.6–3.8, p = 0.148) in patients with psoriasis. Narrow-band ultraviolet B was not a contributory factor (HR 1.15, 95% CI 0.62–2.14, p = 0.66). These findings add evidence that patients with MF have a significantly higher risk of melanoma, not only compared with the general population, but also compared with patients with psoriasis. This comorbidity may be inherent to MF.

Data on the comorbidity of mycosis fungoides with melanoma lack considerations of surveillance bias and treatment as a possible confounder. In this institutional-based series, Israeli patients with mycosis fungoides were found to have a significantly higher risk of melanoma, not only compared with the general population, as reported previously, but also compared with patients with psoriasis followed-up at the same tertiary clinic. Narrow-band ultraviolet B treatment was not a contributory factor. Repeated meticulous skin examination with a focus on melanoma detection is therefore paramount in patients with mycosis fungoides.

Table SI
Table SII