Endocrine Abstracts

Introduction: We present a rare case of squamous cell carcinoma of the sphenoid sinus presenting as a sellar mass and panhypopituitarism.

Case presentation: A 60-year-old Chinese male with schizophrenia and a 20 pack year smoking history, was admitted to our hospital with headache and diplopia without visual field loss. Brain imaging with computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 2.9 cm sellar mass based in the sphenoid sinus, bulging into the suprasellar cistern with post contrast enhancement and pituitary stalk thickening. The optic chiasm was indented, with involvement of the cavernous sinuses and superior portion of the clivus. Subsequent hormonal investigations revealed panhypopituitarism (central hypocortisolism, hypothyroidism and hypogonadism) with hyperprolactinaemia likely from pituitary stalk compression and anti-psychotic medication. There were however no symptoms of central diabetes insipidus (DI). Hormonal replacement with oral hydrocortisone and thyroxine was commenced. An initial biopsy showed focal moderate to severe keratinising dysplasia but no definite invasive malignancy, and a repeat biopsy was planned. Repeat imaging done for worsening symptoms 2 weeks later showed an increase in the size of the sellar mass to 4 cm. Trans-sphenoidal debulking surgery was carried out, and intra-operative biopsy and frozen section revealed the diagnosis of squamous cell carcinoma. Staging CT scans did not reveal any lymph node or distant metastases. Post operatively, patient developed central DI with a biphasic pattern. In view of the advanced intracranial involvement of the tumour, palliative chemotherapy and radiotherapy was planned but patient unfortunately developed progressive worsening neurological deficits likely from tumour progression and passed away.

Conclusion: Squamous cell carcinoma of the sphenoid sinus can rarely present as a sellar mass. Although pituitary adenomas are the most common cause of sellar masses, atypical features such as pituitary stalk thickening or central DI necessitate a high index of suspicion to look for other causes.