Chemotherapy-Induced Regression of an Adrenocorticotropin-Secreting Pituitary Carcinoma Accompanied by Secondary Adrenal Insufficiency
Figure 5
(a) H and E. The tumor in 2011 now has atypical morphologic features including increased nuclear to cytoplasmic ratios and increased nuclear pleomorphism with visible nucleoli. Numerous pyknotic cells and mitotic figures are evident indicating increased cell turnover rate. (b) ACTH stain positivity confirms this tumor as a recurrence of the corticotroph adenoma (c) Ki-67 staining is markedly increased to 80–90%. This high rate alone is not diagnostic of carcinoma but is a worrisome feature. (d) Core biopsy of liver reveals a metastatic malignancy. The morphologic appearance is not specific but is similar to the pituitary lesion. (e) ACTH positivity in the tumor cells confirms the diagnosis of metastatic pituitary carcinoma.
