Subcutaneous tissue involvement by T-cell lymphoma: A report of 2 cases

Background: T-cell lymphomas may involve the subcutaneous tissue as a manifestation of generalized disease. However, T-cell lymphomas rarely present with extensive involvement of the subcutaneous fat without other sites of disease. Observations: We describe 2 women who presented with fever and subcutaneous nodules or masses. In case 1, the nodules were generalized and did not respond to chemotherapy. The patient died 2 months after diagnosis. In case 2, the mass was large but localized and responded to chemotherapy. The tumor subsequently recurred in a cervical lymph node 9 months later, and the patient was being treated with chemotherapy 15 months after initial diagnosis. Histologically, biopsy specimens from both patients revealed malignant lymphoma involving the subcutaneous tissue. The dermis and epidermis were not involved. At low power the lesions re sembled panniculitis, but high-power examination revealed cytologic atypia of the malignant lymphoid cells. Immunohistochemical studies revealed T-cell lineage. In case 2, the neoplastic cells also expressed the CD30 antigen, were positive for Epstein-Barr virus RNA, and carried the t(2;5)(p23;q35) chromosomal translocation. We interpreted case 1 as an example of subcutaneous panniculitic T-cell lymphoma. We believe that case 2 is best classified as anaplastic large cell lymphoma of T-cell lineage. Conclusions: A variety of T-cell lymphomas rarely present with only subcutaneous tissue involvement. Knowledge of this phenomenon and recognition of the cytologic atypia of the lymphoid cells will help to prevent misdiagnosis.