Hypopigmented mycosis fungoides mimicking leprosy successfully treated with oral and topical corticosteroids: a new great imitator?

Hypopigmented mycosis fungoides (HMF) is a rare variant of patch stage MF, which is often misdiagnosed. A 35-year-old male presented with non-pruritic white patches on his chest that had been present for 10 years. The patient had previously been treated for leprosy without any improvement. Physical examination showed well-defined multiple hypopigmented patches and macules on the chest, posterior trunk, and gluteus, with some lesions exhibiting anhidrosis and central erythema. The result of sensibility examination was unclear. Slit-skin-smear examination for acid-fast bacilli and anti-phenolic-glycolipid-1 examination were negative. Histopathological examination showed Pautrier microabscesses. The patient was diagnosed with HMF and was treated with 16 mg methylprednisolone b.i.d., topical application of desoximetasone, and 1% methoxsalen lotion followed by sun exposure. A significant improvement was observed during the following 6 months. This case shows that HMF needs to be considered in patients presenting with chronic unexplained hypopigmented patches to avoid unnecessary treatment and progression to more advanced stages.