味覚異常を主訴とした側頭頭頂葉脳腫瘍例

抄録

Herein, we describe a rare case of gustatory disturbance caused by an astrocytoma of the left temporal-parietal lobe. A 65-year-old woman presented with a 1-month history of dysgeusia and a sense of discomfort in the oral cavity, pharynx and larynx. ENT examination showed slight papillary atrophy in the tongue. Qualitative and quantitative assessment of taste perception was performed. Electrogustometry revealed no abnormalities. Evaluation of taste acuity by the filter paper disc method showed poor recognition threshold in the area of the left chorda tympani nerve, left glossopharyngeal nerve and right greater petrosal nerve. During this examination, the patient’s complaints included parageusia, hypergeusia, and mild paresthesia. When bitter taste was presented in the area of the left greater petrosal nerve, the patient complained of mild pain. Dissociation between the detection threshold and recognition threshold was observed. The gustatory disturbance gradually worsened, with the patient began to complain of a constant feeling of bitter taste and paresthesia in the regions of the oral cavity, pharynx and larynx, in spite of zinc replacement therapy. The patient later developed dysarthria and headache. A brain MRI revealed a left temporal-parietal lobe tumor. Thus, in patients with a short history of dysgeusia who show no recovery within 3 months, more detailed examination needs to be performed to identify the possible cause of dysgeusia. Laterality and aggravation of the gustatory disturbance with time seem to be important clues pointing towards a brain tumor. In particular, patients with gustatory disturbance accompanied by paresthesia of the oral cavity, pharynx and larynx need to be carefully followed up.