Large cell transformation of mycosis fungoides： a case report

The clinical course of mycosis fungoides is indolent except when large cell transformation occurs. Large cell transformation of MF is rare and easy to misdiagnose. A case of large cell transformation of mycosis fungoides is reported. A 40-year-old man presented with a 10-year history of pruritic erythema and papules in the trunk and extremities as well as a 5-month history of nodules on the nape of the neck.Histopathologically, the erythematous patch showed typical changes of mycosis fungoides, while the tumor cells were small and expressed CD3 and CD4, and only a small number of tumor cells expressed CD30. Pathological examination of nodular lesions revealed the infiltration of large pleomorphic lymphoid cells expressing CD3 and CD4 throughout the entire dermis. There was an epidermotropism of large cells, and about 40% of these cells expressed CD30. Based on the medical history and histological findings, the patient was diagnosed with large cell transformation of mycosis fungoides. The lesions improved markedly after 3-week treatment with oral acitretin （30 mg once daily）, subcutaneous interferon-alpha （2 × 106 IU thrice a week） and local superficial X-ray irradiation for nodular lesions. Up to the time of this writing, the patient had been followed. Key words: Mycosis fungoides;  Large cell transformation;  Antigens, CD30