Endocrine Abstracts

Context: Kallmann syndrome (KS) is a developmental disease associating congenital hypogonadotropic hypogonadism (CHH) and sense of smell impairment owing to olfactory structures (OS) aplasia/hypoplasia. Although rhinencephalic MRI allows to detect specific KS OS abnormalities useful to discriminate KS from normosmic CHH (nCHH), this technique is not efficient enough to study anterior skull bone structures.

Objectives: To search for specific anterior skull base abnormalities in KS through CT scan.

Patients: Thirty seven KS patients were compared to matched nCHH (n=15) and controls (n=30).

Design: Prospective case–control study. All patients and controls underwent a high resolution three-plane CT scan in bone window with axial, coronal and sagittal reconstructions. Olfactory gutter (OG) height, width, surface and foveo-lateral angle were measured. Cribriform plate foramina were counted bilaterally. Rhinencephalic MRI were performed in parallel and OS abnormalities were scored as normal, hypoplasic or aplastic and compared to CT scan findings.

Results: In KS patients OG height, width and surface were all significantly lower than in nCHH and controls (P<0.0001). OG height <3.6 mm discriminates KS with the higher sensitivity and specificity. A correlation between OG height at CT scan and OS abnormality scores at MRI was found. KS subjects also presented a wider foveo-lateral angle than nCHH and controls (P<0.0001). Cribriform plate foramina median number was similar in KS, nCHH and controls (7 vs 8 and 9 respectively).

Conclusions: This study allowed us to discover specific ethmoid abnormalities in KS patients. OG height <3.6 mm at CT scan specifically discriminates KS from nCHH, providing a new diagnostic tool. The presence of cribriform plate foramina in KS patients indicates that OS integrity is not mandatory for their formation and maintenance, unraveling original aspects on KS pathophysiology.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.