Hyponatremia: A Tip of the Iceberg in the Late Diagnosis of Tuberous Sclerosis Associated with Lymphangioleiomyomatosis.

Tuberous sclerosis (TS) is a rare, autosomal dominant, multisystem genetic disease that causes multiple benign tumors in the brain and other vital organs. Rarely, it can be associated with lymphangioleiomyomatosis (LMA) that is characterized by the proliferation of immature smooth muscle cells in the walls of the airways, venules, and lymphatic vessels in the lung. Here, we present the case of a 44-year-old intellectually disabled woman with a history of marked polydipsia who presented to the emergency department with persistent vomiting. She was hemodynamically stable and did not have any fever. The analytical study showed severe and symptomatic hyponatremia. On physical examination, multiple skin lesions compatible with angiofibromas were noted and the diagnosis of TS was made (confirmed with the genetic study). The multiorgan study documented the presence of multiple cystic images in the lung parenchyma associated with LMA. The aim of this case report is to highlight the importance of targeting cutaneous lesions for a rapid diagnosis of this pathology and to identify the etiology of a severe (symptomatic) ionic disorder and referral to a multidisciplinary team.