Adie’s Tonic Pupil Disclosing a Metastatic Breast Cancer: Case Report

Abstract

Tonic pupil, or Adie’s pupil, is an autonomic disorder due to a loss of function of parasympathetic ciliary ganglion cells. Upon examination, the pupil appears tonically dilated and shrinks poorly to light, while reacting better to accommodation stimulus. The denervated iris sphincter is very sensitive to topical parasympathomimetic pilocarpine drops. Indeed, if Adie is present, the dilated pupil will constrict more than the normal pupil. Most cases are idiopathic or due to a viral infection and have a benign course. They usually occur in women between 20 and 40 years of age. Other reported causes of tonic pupils can be vascular, traumatic, inflammatory, paraneoplastic, and neoplastic. Breast cancer generally metastasizes to the brain in advanced stages and orbital localizations have sometimes been reported. In our case, a meningeal and retro-orbit cancer invasion caused a dysfunction of the parasympathetic fibers which lead to the pupil through the optical foramen. Indeed, first ophthalmic symptoms were only an enlarged pupil poorly responsive to light. This unusual clinical sign led to the discovery of an unknown breast cancer in an advanced stage. In young adult women, unilateral tonic pupils are considered a benign parasympathetic ocular disorder that is rarely observed in clinical practice. However, it can be found in numerous systemic diseases; thus instrumental and laboratory findings are mandatory. Tumors can also represent etiologic agents and secondary localizations from breast cancer to extra parenchymal CNS structures should be considered in differential diagnosis hypothesis.