Mycosis fungoides is the most common primary cutaneous T-cell lymphoma with an indolent course. Typical manifestations include erythematous patches and plaque-type lesions, with about 25% of cases progressing into nodules and tumors. This case 
was presented at the Department of Dermatology, Mugda Medical College Hospital, in May 2023. A 60-year-old Bangladeshi male presented with diffuse infiltrative erythematous plaques and ulcerated pustules on the skin of his upper body for six months. The initial clinical diagnosis was exfoliative dermatitis, but a skin biopsy confirmed mycosis fungoides through mmunohistochemistry. The patient later developed generalized lymphadenopathy. The immunohistochemistry findings of a ymph node biopsy revealed nodal involvement of the disease. Systemic chemotherapy was initiated, but he unfortunately passed away due to neutropenic sepsis. This case highlights the importance of early diagnosis in mycosis fungoides, a disease that can often be mistaken for inflammatory dermatoses. Early skin biopsy with immunohistochemistry can lead to an early diagnosis of MF, potentially changing the course and outcome of the disease.