Unveiling Mycosis Fungoides: The Diagnostic Challenge Requiring Multiple Skin Biopsies

Mycosis fungoides is a rare malignant skin neoplasm. It is the most prevalent primary cutaneous T-cell lymphoma. Hypopigmented mycosis fungoides, a variant, has been observed in Asian and dark-skinned individuals. We present a case of a twenty-four years old Nepalese woman with multiple asymptomatic hypopigmented macules on her arms, thighs, abdomen and back. The patient was treated with topical steroids, oral steroids, and topical psoralen with UVA phototherapy for suspicion of vitiligo and Pityriasis lichenoides chronica. After multiple biopsies, histopathology revealed an epidermis with focal subtle vacuolization in junctional zone and epidermotropic small and slightly enlarged lymphocytes with irregular nuclei. Immunohistochemistry showed increased CD4:CD8 ratio. Hypopigmented mycosis fungoides occurrence is infrequent not only in our region but also in Western literature. Recognizing hypopigmented mycosis fungoides as a rare condition and including it in the differential diagnosis of hypopigmented dermatological conditions can aid physicians in early diagnosis and reduce morbidity and mortality through appropriate management and care.