Mary Wu Chang, MD

The main diagnostic challenge in this rare condition is differentiating it from pityriasis lichenoides chronica; prognosis is usually favorable.

Childhood mycosis fungoides (MF) is rare, and literature is scant. Investigators reviewed 46 cases of patients younger than 16 years diagnosed with MF between 2000 and 2008 in Singapore. Diagnosis was confirmed using International Society for Cutaneous Lymphomas criteria; all had unequivocal histopathologic features on at least one skin biopsy. Mean age at diagnosis was 10 years; mean symptom duration before diagnosis was 24 months. The male:female ratio was 2.3:1.

Thirty-one patients had hypopigmented lesions only; 11 had predominantly hypopigmented lesions with some red, scaly papules or plaques; 3 had predominantly red scaly papules or plaques; 1 had only brown patches. Seven had atrophic skin lesions. Nineteen patients had provisional MF diagnoses at presentation; 11 were diagnosed with pityriasis lichenoides chronica (PLC), 11 with eczema-related postinflammatory hypopigmentation. Ultimately, 91% were diagnosed with a hypopigmented variant of MF; one case each was diagnosed with PLC-like MF, pigmented purpuric dermatosis-like MF, classic MF, and solitary MF. Coexisting pityriasis lichenoides was histologically proven in three patients. All patients had stage IA or IB disease, except one with stage IIA disease.

Treatments included narrowband ultraviolet B (NBUVB) phototherapy (32 patients), topical steroids alone (8), psoralen with ultraviolet A (PUVA; 3), and ultraviolet A1 phototherapy (1). Complete clearance occurred after a mean of 27 months in 27 patients. Of 32 NBUVB recipients, 15 had complete clearance within an average 9 months, but 7 relapsed within 15 months. One patient had difficult-to-treat solitary MF.

Citation(s):

Heng YK et al. Pediatric mycosis fungoides in Singapore: A series of 46 children. Pediatr Dermatol 2014 Jul/Aug; 31:477.