Difficulty differentiating a case of posterior cortical atrophy from a psychogenic disturbance of vision

Differentiating posterior cortical atrophy (PCA) from other diseases can be difficult and time‐consuming, and there is a particularly high possibility of misdiagnosis when psychiatrists diagnose complaints related to visual perception. Here, a case of PCA involving prominent visual perceptual disorders is reported; PCA was difficult to distinguish from psychogenic disturbance of vision in this case. For a year, a 59‐year‐old woman had had visual perceptual disorders, including a distorted view and prosopagnosia. She underwent examinations at multiple clinical departments at several medical institutions before receiving a definitive diagnosis of PCA. This PCA diagnosis was based on clinical symptoms, including Gerstmann syndrome, Bálint's syndrome, and transcortical sensory aphasia, and hypoperfusion in the occipital lobe observed on single‐photon emission computed tomography. This case was initially misdiagnosed as a psychogenic disease partly because characteristic clinical manifestations of PCA include visual agnosia with a disjunctive component. This patient displayed a disordered perception of stationary objects but an intact perception of moving objects. For example, she had to grope her way through a room at home, but she could visit a familiar hair salon on foot without hindrance. Behaviours like claiming to be blind while inexplicably moving without colliding with surrounding objects may lead to the misdiagnosis of PCA as a psychogenic or dissociative disorder involving histrionic or neurologically irrational symptoms with an expectation of sympathy or personal gain. It is critical to make every effort to exclude organic diseases, even in cases provisionally diagnosed as psychogenic disease. Despite its low prevalence, PCA should be considered a syndrome caused by Alzheimer's disease, dementia with Lewy bodies, or other dementias.