"Lymphosarcoma" refers to a lymphatic malignant process which may appear in either a localized or a systemic form. The term originally designated the localized neoplasm which is now often recognized as a phase of the systemic disease. Lymphosarcoma has been separated into two types, depending on the histologic characteristics of the predominant cell. There is a reticulum or "large-cell" type, and there is a "small-cell" type. The "small-cell" type is further divided into lymphocytic and lymphoblastic varieties. Lesions on the skin appear in all types of lymphosarcoma and may seem to be clinically similar. Usually they are associated with systemic lymphatic involvement and only rarely arise as primary cutaneous lesions. In a category of unusual cases are those in which the process is first recognized in the so-called extralymphatic tissues (that is, tissues which normally contain no lymphocytes) and simultaneously involves the skin. Testicular lymphosarcoma represents one of these rare