Clinical and molecular assessment of cystic sellar salivary gland-like lesions.

Background: Symptomatic sellar salivary gland-like lesions (SSGLs) are uncommon, with fewer than two dozen case reports. Prior case reports have also not detailed pre- or postoperative endocrinopathies to determine if these lesions can be clinically distinguished prior to biopsy from Rathke cleft cysts (RCCs). In addition, prior molecular testing was attempted to provide further insights as to whether these might be developmental lesions or true neoplasms, but testing was unsuccessful.

Materials and methods: Report of 2 new cases of SSGLs with molecular testing to assess for potential gene mutations, copy number alterations, and fusions with literature review detailing demographic, clinical, endocrinological, neuroimaging, histological, and outcome features.

Results: A 53-year-old female and 33-year-old male developed large sellar lesions. The woman presented with fatigue and sudden-onset visual changes and the man with apoplectic-like severe headache. Biopsy specimens for both patients demonstrated clusters of histologically benign salivary gland-like acini accompanied by varying amounts of mucin and lymphocytic inflammation. None showed pituitary tumor. Postoperatively, one case developed persistent diabetes insipidus. Molecular testing revealed a lack of pathogenic mutations, copy number alterations, or gene fusions in both cases.

Conclusion: SGGLs differ histologically and sometimes in size from RCCs, although both can be cystic, contain abundant mucin, and may result in postoperative transient or permanent diabetes insipidus; they cannot be completely distinguished preoperatively from RCCs. Molecular testing did not demonstrate any mutations, copy number changes, or fusions for either case. Lack of pathogenic genetic alterations suggest these lesions may not be true neoplasms.