Clinical Significance of Granulation Pattern in Corticotroph Pituitary Adenomas

The granulation pattern of pituitary tumors may be important to predict tumor behavior, treatment outcomes, and recurrences. Therefore, we compared densely granulated corticotroph tumor (DGCT) and sparsely granulated corticotroph tumor (SGCT) in terms of clinicopathologic findings.

A total of 41 patients (31 females/10 males) were assessed in the study. The granulation patterns were detected by Periodic Acid-Schiff (PAS) and adrenocorticotropic hormone (ACTH) immunoreactivity. Diffuse and strong staining by PAS and ACTH were identified as DGCT, whereas faint staining by PAS and focal, weak staining by ACTH were identified as SGCT. Perinuclear ring-like patterns with low molecular weight keratin were identified as Crooke's cell tumors. DGCTs and SGCTs were compared in terms of clinical findings and treatment outcomes.

The majority of the patients (71%) had DGCTs (n=29); whereas 24% of the patients had SGCTs (n=10) and 5% of the patients had Crooke's cell tumors (n=2). DGCTs and SGCTs were similar in terms of age, sex, estimated duration of disease, baseline cortisol and ACTH levels. SGCTs were larger than DGCTs (p=0.034). The remissions with surgery rates were similar between the groups; however, hypothalamic-pituitaryadrenal axis recovery time was longer in SGCTs (p=0.033). Persistent disease after surgery was slightly higher in DGCTs and recurrences were frequent in SGCTs; however, the differences were not statistically significant.

DGCTs are often small microadenomas, while SGCTs are larger. Recurrences were slightly more common in SGCTs; however, further studies including larger series are needed to be able to obtain more significant results.