Pityriasis Lichenoides-like Mycosis Fungoides in Children: A Challenging Diagnosis

Primary cutaneous lymphomas are rare diseases among the general population, and even rarer in children. Mycosis fungoides (MF) is the most commonly diagnosed form in childhood. Several atypical clinical variants of MF have been reported, and pityriasis lichenoides-like MF (PL-like MF) is a recently described subtype. We report about a rare case of PL-like MF in an 11-year-old Malay boy with a 2-year history of multiple scaly erythematous papules associated with progressive and generalized hypopigmentation. This case report illustrates the significant dilemma in the diagnosis of the disease, particularly in the early stages, because its symptoms can mimic those of many common childhood inflammatory skin disorders. Later, the widespread hypopigmentation obscured the characteristic lesions, leading to misdiagnosis. Moreover, due to unfamiliarity of the disease, the diagnosis of PL-like MF was missed and delayed until only 2 years after the onset of the dermatosis. Therefore, primary care practitioners must have a high index of suspicion for this cutaneous neoplasm in children with persistent or worsening skin lesions, not responding to standard therapy, to ensure timely referral, diagnosis, and treatment.