2025 Volume 40 Issue 2 Pages 127-132
An 89－year－old male presented with an enlarging oval mass in the right posterior neck that had been first noticed two months prior to the initial consultation. On examination, a 25－mm－sized reddish lesion with surface erosion was observed. Biopsy revealed diffuse proliferation of small－to medium-sized and some large atypical lymphocytes, positive for CD8 and CD30 throughout the dermis and subcutaneous fat, with mild epidermotropism. Immunohistochemistry revealed that the atypical cells were partially positive for granzyme B and negative for ALK. Southern blot analysis demonstrated monoclonal rearrangements of T－cell receptor β chain and γ chain. No involvement of lymph nodes or other organs was detected by computed tomography. Given the solitary indolent lesion and characteristic histopathological findings, a diagnosis of CD8－positive primary cutaneous anaplastic large cell lymphoma was made. Local radiotherapy was administered, which resulted in regression of the tumor after three months.[Skin Cancer (Japan) 2025 ; 40 : 127－132]
