The general practitioner is often called on to diagnose and treat various types of skin disorders. Many of these are local conditions peculiarly confined to the skin, whereas others are definite cutaneous manifestations of some systemic disease. Some run a benign course, while others are expressions of a neoplastic process. Any discussion that will aid the physician in arriving at a diagnosis or arouse his suspicions that he is dealing with a cutaneous expression of some hidden visceropathy seems worth while. With this in view, a general discussion of the lymphoblastomas would seem to be of value. In this discussion the term lymphoblastoma is used to designate certain diseases of the hematopoietic system. Those which often give rise to cutaneous manifestations are Hodgkin's disease, mycosis fungoides, the leukemias (both myeloid and lymphocytic) and lymphosarcoma. Occasionally these manifest themselves here before their demonstration in other parts of the body is possible.