Clinical Features and Treatment of Secondary Pituitary Abscess After Transsphenoidal Surgery: A Retrospective Study of 23 Cases

•Our study retrospectively collected 23 cases of secondary PA after TS, which were the largest case series to our knowledge.•Patients with an initial diagnosis of Rathke's cleft cyst or pituitary macroadenoma were more likely to have PA after TS.•Based on the history of TS, clinical presentation, and typical imaging features, the preoperative diagnosis rate was 78%.•Surgical drainage by TS approach, followed by microbiology-guided antibiotic therapy, should be the standard treatment.•Secondary PA is a severe but neglected complication after TS. Related articles about secondary PA after TS are limited.