Involvement of the central nervous system in the course of acute or chronic myelogenous leukemia is not unknown. As emphasized by Critchley and Greenfield1in their discussion of cord symptoms in leukemia and chloroma, the pathologic manifestations in such cases may be of several kinds. Localized collections or "tumor formations" of the abnormal white blood cells in the meninges are most common, according to these authors. The cases reported in their article of four males aged 19 years or younger were featured by the presence of such leukemic or chloromic masses in the epidural or subarachnoid spaces. In addition, however, a special finding in three of the cases was invasion of the spinal and cranial nerve roots by the myeloid elements, which in these cases apparently accounted, at least in part, for the radicular pains and other disturbances (including peripheral facial and palatal palsies, as well as unilateral deafness)