Diagnostic criteria in Pai syndrome: results of a case series and a literature review

Int J Oral Maxillofac Surg. 2019 Mar;48(3):283-290. doi: 10.1016/j.ijom.2018.08.010. Epub 2018 Sep 6.


Pai syndrome was originally described as the association of a midline cleft lip, midline facial polyps, and lipoma of the central nervous system. However, only a few patients present with the full triad, and most exhibit a wide spectrum of phenotypic variability. The aim of this study was to phenotypically delineate Pai syndrome and to propose new criteria to facilitate a clinical diagnosis in the future. The study cohort consisted of seven case patients and an additional 60 cases diagnosed with Pai syndrome identified in a literature review. Only 23 of 67 patients presented the full triad as historically described by Pai et al. (1987). A congenital facial midline skin mass was always encountered, particularly affecting the nasal structures (60/67). A midline facial cleft was reported in 45 of 67 patients and a pericallosal lipoma in 42 of 67 patients. The proposed definition of Pai syndrome is the association of (1) a congenital nasal and/or mediofrontal skin mass and/or a mid-anterior alveolar process polyp as a mandatory criterion, and at least one of the following criteria: (2) midline cleft lip and/or midline alveolar cleft, and/or (3) a pericallosal lipoma or interhemispheric lipoma in the case of corpus callosum dysgenesis.

Keywords: Pai syndrome; frontonasal dysplasia; midline cleft lip; pericallosal lipoma; skin tag.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adolescent
  • Agenesis of Corpus Callosum / diagnosis*
  • Agenesis of Corpus Callosum / genetics
  • Agenesis of Corpus Callosum / pathology
  • Child
  • Child, Preschool
  • Cleft Lip / diagnosis*
  • Cleft Lip / genetics
  • Cleft Lip / pathology
  • Coloboma / diagnosis*
  • Coloboma / genetics
  • Coloboma / pathology
  • Diagnosis, Differential
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Lipoma / diagnosis*
  • Lipoma / genetics
  • Lipoma / pathology
  • Magnetic Resonance Imaging
  • Male
  • Nasal Polyps / diagnosis*
  • Nasal Polyps / genetics
  • Nasal Polyps / pathology
  • Phenotype
  • Skin Diseases / diagnosis*
  • Skin Diseases / genetics
  • Skin Diseases / pathology
  • Young Adult

Supplementary concepts

  • Median cleft lip, corpus callosum, lipoma, and skin polyps