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An ACTH-producing pituitary carcinoma developing Cushing's disease
T Masuda1, Y Akasaka, Y Ishikawa
1Department of Pathology, Toho University School of Medicine, Tokyo, Japan. masudatk@med.toho-u.ac.jp
Pathology, Research and Practice
|April 30, 1999
Summary
This case report details an ACTH-producing pituitary carcinoma initially misdiagnosed as adenoma. Autopsy confirmed widespread metastases, highlighting the importance of Ki-67 in assessing pituitary tumor malignancy.
Area of Science:
- Endocrinology
- Oncology
- Neuropathology
Background:
- Cushing's disease can be caused by pituitary tumors, typically adenomas.
- Pituitary carcinomas are rare but aggressive tumors with metastatic potential.
Observation:
- A 59-year-old man with Cushing's disease had a pituitary tumor initially diagnosed as a chromophobe adenoma.
- Two years post-surgery, pulmonary metastases were detected, leading to autopsy.
- Autopsy revealed residual pituitary tumor with extensive systemic metastases.
Findings:
- Immunohistochemistry confirmed ACTH production by the pituitary tumor cells.
- High Ki-67 expression was observed in both the surgically removed and autopsied tumors.
- The Ki-67 labeling index indicated significant invasive and proliferative potential.
Implications:
- This case underscores the diagnostic challenges in distinguishing aggressive pituitary adenomas from carcinomas.
- High Ki-67 expression serves as a crucial biomarker for predicting pituitary tumor invasiveness and metastatic risk.
- Accurate diagnosis and assessment of proliferative potential are vital for managing patients with pituitary tumors.