A case of post-mogamulizumab relapse of acute-type adult T-cell leukemia/lymphoma successfully treated with mogamulizumab and etoposide.

A 70-year-old man presented to us with the chief complaints of a generalized rash and a mass in the right clavicular region that he first noticed in the year 2012. Biopsy of the mass led to the diagnosis of cutaneous nodular mass-type adult T-cell leukemia/lymphoma (ATLL) in March 2013. Phototherapy was started, and the symptoms improved temporarily. However, in late June 2013, the serum lactate dehydrogenase (LDH) level increased to 358 IU/L, which was 1.6 times higher than the upper limit of the reference range; based on the findings, transformation of the disease to the acute type was diagnosed. The patient was treated with 6 courses of CHOP therapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone), which resulted in complete remission (CR). However, the rash recurred in late October 2013, and treatment with mogamulizumab was initiated. A total of 8 courses of mogamulizumab were administered, which resulted in CR. The rash and cutaneous nodular masses recurred again in January 2014, and a total of 8 courses of mogamulizumab were administered again starting in February 2014. However, the patient's symptoms began to worsen gradually. Phototherapy was also initiated, but had to be discontinued due to the development of photosensitivity. Treatment with the combination of mogamulizumab and etoposide (25 mg/day for 21 days) was started in May 2014. The nodular mass rapidly decreased in size. The rash or cutaneous nodular mass had not recurred as of August 2014. Thus, combined therapy with mogamulizumab plus etoposide is considered to be effective for resolution of the cutaneous nodular masses in patients with ATLL.