Superior Lingular S4 Segmentectomy.

Although segmentectomy has become a routine procedure, atypical segmentectomies are less popular than their typical counterparts, probably because anatomical and surgical data are lacking. The left superior lingular S4 segment is considered relatively small, usually resected along with other segments. However, S4 segment size varies among patients, and resection of this single segment can be a valuable lung-preserving procedure in carefully selected patients with tumors located at the border of the upper division and lingular segments. We present here the anatomical and surgical features required for a methodological left S4 segmentectomy based on our experience and the literature.