Ki-1 (CD30)-positive anaplastic large cell lymphoma, sarcomatoid variant accompanied by spontaneously regressing lymphadenopathy

Although it has been reported that primary Ki-1 (CD30)-positive anaplastic large cell lymphoma (ALCL) of the skin may undergo spontaneous regression, it is rare for ALCL without cutaneous involvement to have spontaneously regressing lymphadenopathy. We report a case of sarcomatoid variant of ALCL accompanied by spontaneously regressing lymphadenopathy. The patient had gastric and pulmonary involvement of ALCL in addition to systemic lymphadenopathy, but with no cutaneous involvement. The lymphadenopathy spontaneously improved gradually during a period of one month without any treatment. At the same time, multiple small nodules in both lung fields decreased on chest computed tomography and multiple elevated gastric tumors with dimples were endoscopically recognized to have improved. He has since been treated with combination chemotherapy because of recurrence of the lymphadenopathy.