Recurrent Corticotropic Pituitary Adenoma Treated Successfully with Temozolomide: A Case Report

Background: Treatment of recurrent or invasive pituitary adenomas is often challenging and new methods are being attempted at control of tumor growth as well as biochemical remission. Functional corticotroph secreting tumors are particularly important given the severity of symptoms of Cushing’s disease. There has been previous work in using chemotherapeutic agents to treat pituitary neoplasms with little success; however, temozolomide is a newer and usually very well tolerated chemotherapeutic agent with some limited data to support use in these patients.

Case Description: We describe a case involving a 58-year-old female presenting with headaches and new worsening visual field deficit in the setting of Cushing’s disease. She had had previous partial resection via transsphenoidal route and at the second operation via transcranial approach, the tumor was not able to be completely resected due to invasion of vital structures. Interestingly the tumor became more positively staining for ACTH between the two operations ([Fig. 1]). The residual tumor was treated with temozolomide as a salvage therapy, and the patient achieved improvement in her symptoms as well as decrease in the size of her tumor on subsequent imaging with stabilization of her ACTH levels ([Fig. 2]).

Conclusion: Temozolomide is a safe and generally well-tolerated chemotherapeutic agent that may be a useful adjunct in the treatment of pituitary adenomas that are not amenable to complete resection or that remain refractory to other treatment modalities.

Fig. 1 Both hematoxylin and eosin stained slides in the upper portion demonstrate sheets of pituicytes lacking normal pituitary architecture. The cells have moderate amounts of granular eosinophilic cytoplasm and round nuclei with mild pleomorphism. Below the tumor in the first resection shows weak cytoplasmic staining for ACTH that intensifies to being strongly positive in the second resection.

Fig. 2 T1-weighted axial (upper), coronal (middle), and sagittal (lower) MRI with contrast from left to right: preoperative 2013, preoperative 2018, postoperative 2018, and then 3 months post-temozolomide.