In a 78-year-old Japanese male cadaver, cavum septi pellucidi (CSP) and corpus callosum with fistula communicated with longitudinal cerebral fissure were found. Cingulate gyri were bilaterally protruded into longitudinal cerebral fissure. CT images before death confirmed CSP and irregular surfaces of cingulate gyri. Enlarged CSP have often been described in patients with schizophrenia. This case provides a possible association of CSP with morphological abnormalities, especially enlargement of cingulate gyri and fistula through corpus callosum, which may be overlooked in a routine clinical neuroimaging.