AB009. Distinct clinical profiles and treatment outcomes in invasive pituitary adenoma and Crooke cell tumor: a comparative case report

Background: Pituitary adenomas, particularly invasive pituitary adenomas and Crooke cell tumors, represent significant neuroendocrine tumors with diverse clinical and pathological profiles. Invasive pituitary adenomas are known for their aggressive growth and potential to invade surrounding structures, leading to notable endocrine and neurological complications. Crooke cell tumors, a rare variant of corticotroph adenomas, are characterized by Crooke cells—basophilic cells with cytoplasmic changes due to prolonged glucocorticoid exposure. Although these tumors have aggressive histological features, their clinical behavior can vary widely, often determined by their proliferative index, such as Ki-67. This case report presents two patients with pituitary adenomas, highlighting the contrasting clinical courses, management strategies, and pathological findings.

Case Description: Case 1 features a 42-year-old Asian male, initially diagnosed with a 3-cm pituitary macroadenoma at 23 years, experienced symptoms of blurred vision. Elevated adrenocorticotropic hormone (ACTH) levels were noted. Despite transnasal transsphenoidal surgery and subsequent interventions, including radiotherapy, the tumor recurred multiple times, leading to significant visual and neurological complications. Pathological assessments consistently showed an ACTH-positive adenoma with increasing markers of aggressiveness, including a Ki-67 index up to 5%. The patient was eventually diagnosed with Cushing’s disease. Case 2 discusses a 56-year-old male who was incidentally found to have a pituitary tumor during a routine health check, with no visual symptoms despite optic nerve compression. Post-surgery, pathology revealed a Crooke cell tumor with a Ki-67 index of 1%. The patient had an uneventful recovery and no recurrence, with normal hormonal levels throughout follow-up.

Conclusions: These cases underscore the heterogeneity of pituitary adenomas, emphasizing the importance of the Ki-67 index as a prognostic marker. While invasive adenomas often require aggressive multimodal therapy, Crooke cell tumors with low proliferative indices can be effectively managed with surgery alone. A multidisciplinary approach is crucial for optimizing patient outcomes in the management of these tumors.

Keywords: Invasive pituitary adenoma; Crooke cell tumor; case report