Brain tumors are the rarest cause of cerebrospinal fluid rhinorrhea. Non-traumatic cerebrospinal fluid rhinorrhea is also a relatively rare condition. It may be misdiagnosed as allergic rhinitis or chronic sinusitis and lead to unsuitable treatment. We described a 34-year-old man who came to our allergy clinic with a chief complaint of clear rhinorrhea from his left nostril with more than four years of duration. Onlyhypertrophy of left inferior concha was found in the clinical examination. His rhinorrhea aggravated when bending forward. So we were suspicious of CSF rhinorrhea. MRI was done for him and demonstrated a large tumor in the pineal region. The patient underwent surgery with resection of the mass via an infratentorial-supracerebellar approach. This case showed the role of maintaining differential diagnosis for a common complaint; rhinitis which is seen as usual.
Keywords: Brain tumor; Cerebrospinal fluid; Rhinitis; Rhinorrhea.