Hypopigmented mycosis fungoidesC84.0

Variant of mycosis fungoides with hypopigmented or depigmented patches and plaques occurring mostly in children belonging to skin type IV-VI according to Fitzpatrick. These can occur in combination with erythematous and, less frequently, hyperpigmented lesions (Boulos S et al. 2014; Castano E et al. 2013).

The hypopigmented variant is the most common variant of childhood mycosis fungoides, accounting for 60% (Heng YK et al. 2014).

V.a. in children and adolescents. In <10% of all cases of mycosis fungoides this variant is detectable in adults.

Epidermotropic T-cell infiltrate (small to medium-sized lymphocytes, comparable to the infiltrate in classic mycosis fungoides).

Vitiligo, postinflammatory hypopigmentation, pityriasis alba.

Most juvenile MF patients are diagnosed at an early stage of the disease. In most cases, local therapies are used that are similar to adult MF.

First-line treatment: The most commonly used treatment modality is narrow band UVB (NB-UVB) therapy sometimes in combination with topical steroids.

Second-line treatment: PUVA

Alternative: Topical or oral retinoids

Advanced MF: In this case, systemic treatments become necessary (in the context of clinical trials). The antibody-drug conjugate brentuximab vedotin and the anti-chemokine receptor 4 monoclonal antibody mogamulizumab, both drugs approved for the indication of MF, have been described (Kim YH et al 2018; Prince HM et al 2017). Data on the efficacy of brentuximab vedotin in children are available for the treatment of relapsed or refractory Hodgkin's lymphoma or systemic anaplastic large cell lymphoma, but are lacking for juvenile MF (Wieser I et al. 2016).

Most patients (both children and adults) with hypopigmented MF have a good prognosis. Children who present with both hypopigmented and reddened patches and plaques seem to have a worse prognosis (tendency to progress to plaque and tumor stage (Castano E et al. 2013).

In most published cases, the follow-up period was limited, which complicates the medium- and long-term prognosis. In this respect, considering the longer life expectancy of adolescent patients, systematic long-term observations are recommended in order to detect a renewed relapse activity at an early stage and to be able to treat it again.

1. Castano E et al. (2013) Hypopigmented mycosis fungoides in childhood and adolescence: A long-term retrospective study. J Cutan Pathol 40: 924-934.
2. Boulos S et al. (2014) Clinical presentation, immunopathology, and treatment of juvenile-onset mycosis fungoides: A case series of 34 patients. J Am Acad Dermatol 71: 1117-1126.
3. Heng YK et al (2014) Pediatric mycosis fungoides in singapore: A series of 46 children. Pediatr Dermatol 31: 477-482.
4. Kim YH et al. (2018) Mogamulizumab versus vorinostat in previously treated cutaneous T-cell lymphoma (MAVORIC): an international, open-label, randomised, controlled phase 3 trial. Lancet Oncol 19: 1192-1204.
5. Koch SE et al (1987) Mycosis fungoides onset in childhood and adolescence. J Am Acad Dermatol17:563-570.
6. Nanda A et al. (2010) Mycosis fungoides in Arab children and adolescents: A report of 36 patients from Kuwait. Pediatr Dermatol 27: 607-613.
7. Nasimi M et al (2020) Childhood mycosis fungoides: A clinicopathologic study of 30 cases from Iran. Australas J Dermatol 61: e259-e261.
8. Prince HM et al. (2017) Brentuximab vedotin or physician's choice in CD30-positive cutaneous T-cell lymphoma (ALCANZA): an international, open-label, randomised, phase 3, multicentre trial. Lancet 390: 555-566.
9. Wieser I et al. (2016) Granulomatous mycosis fungoides in an adolescent - a rare encounter and review of the literature. Pediatr Dermatol 33: e296-2298.