Scintigraphic Improvement of Primary Intestinal Lymphangiectasia in a Patient Treated With Alpelisib for a PIK3CA-Related Overgrowth Spectrum.

A 33-year-old man with primary intestinal lymphangiectasia (Waldmann disease) associated with PIK3CA-related overgrowth spectrum was explored using 99m Tc serum albumin scintigraphy before and during treatment by alpelisib, a specific PIK3CA inhibitor. Before treatment, scintigraphic images evidenced a focal uptake on the right colonic angle 4 hours postinjection (p.i.), diffusing to the transverse and left colon 24 hours p.i., compatible with a diffuse colonic exudation. Significant scintigraphic improvement was observed with a disappearing of the right colonic angle uptake 4 hours p.i. and later images 14 months after alpelisib introduction.