Introduction: Silent corticotroph adenomas (SCAs) are clinically nonfunctioning pituitary adenomas
(NFPAs) with positive staining for corticotropin (ACTH) by immunohistochemistry. SCAs
are a subtype of nonfunctioning pituitary tumor that are believed to behave more aggressively
with a presumed higher risk of recurrence. These tumors typically present in the sellar/suprasellar
space with associated optic nerve/chiasm compression. We report here a series of patients
in whom the tumor presented as an unusual infrasellar clival mass.
Methods: We conducted a retrospective review of all SCA tumors followed at two institutions
over a 9-year period. Out of these, we identified 11 cases of clival tumors that turned
out to be SCA tumors. We reviewed all clinical, radiological, and pathological features.
These patients were then followed up with serial imaging and clinical studies. We
compared these results with the known literature on SCA tumors.
Results: Out of the 11 patients that met inclusion criteria, 55% were men with an average
age of 52 years. The range of follow-up was 6-78 months with an average time of 46
months. Twenty-seven percent of patients presented with visual compromise and 36%
with diplopia. The average tumor size was 4.4 cm in diameter with 36% of patients
displaying cavernous sinus involvement and 90% with clival bony erosion. A gross total
resection (GTR) was only attempted on 36% of patients; 90% of patients received post-diagnosis
radiation therapy (IMRT). Of these, 50% continued to grow in the follow-up period
on serial imaging.
Conclusion: SCA tumors are a distinct pathological subtype of nonfunctioning pituitary tumor
that can present as a primary clival (infrasellar) lesion in a population of patients.
The tumors in this location appear to present at a later age with a larger size and
cavernous sinus invasion compared with other described cases of SCA. These tumors
also present more with CN6 neuropathy than visual compromise, similar to other clival
lesions. The degree of bony invasion and resistance to postoperative radiation therapy
in a subset of these patients may support the thesis that SCAs behave more aggressively
and can easily mimic other clival tumors on presentation. Due to their pathology and
location, a GTR may not be indicated. Careful monitoring of the tumor is important
in the postoperative period as a subset are resistant to standard radiation therapy.
