Unmasking catamenial hemoptysis in the era of CFTR modulator therapy

Background: Thoracic endometriosis syndrome (TES) is a rare condition that occurs in women when endometriosis implants into the thoracic cavity. Catamenial hemoptysis, the occurrence of hemoptysis with menstruation, is a recognized clinical manifestation of TES commonly treated with hormonal therapy. Case summary: We present the first documented case describing the recrudescence of catamenial hemoptysis in the setting of Lumacaftor/Ivacaftor administration in a 25-year-old woman with cystic fibrosis (CF). Discussion: We review the literature on TES, pharmacologic management, and reported cystic fibrosis transmembrane conductance regulator (CFTR) modulator drug interactions. We propose that our patient's recrudescence of catamenial hemoptysis was secondary to a drug-drug interaction between Lumacaftor/Ivacaftor and oral contraceptive therapy. Conclusion: Our case suggests that women with CF who have catamenial hemoptysis and a genetic mutation approved for Tezacaftor/Ivacaftor or Elexacaftor/Tezacaftor/Ivacaftor can be managed effectively with either CFTR modulator and hormonal contraceptive therapy.