Left precentral gyrus and Broca's aphasia: a clinicopathologic study.

We describe an autopsied case in which a circumscribed lesion involving the left precentral gyrus caused mild but lasting Broca's aphasia. The patient developed nonfluent speech and writing disturbances (consistent with mild Broca's aphasia) following malignant lymphoma of the brain. After subtotal resection of the tumor and whole brain irradiation, his language disturbances continued without remarkable change for 3 years until his death. A neuropathologic study indicated that the lesion responsible for the patient's aphasia was restricted to the lower one-third of the precentral gyrus in the left hemisphere. As for the relationship between the left precentral gyrus and Broca's aphasia and its allied syndrome (ie, aphemia), we concluded that in Broca's aphasia the lower part of the precentral gyrus plays a more important role than previously assumed.