Metastatic involvement of the pituitary gland: a systematic review with pooled individual patient data analysis

To report a rare case of pituitary metastasis (PM) from hepatocellular carcinoma (HCC) and help better understand the incidence of PM and its most common presenting symptoms through a pooled individual patient data analysis.

Literature regarding PM was systematically reviewed with a pooled individual patient data analysis conducted. Pooled individual data analysis result is also compared with the result in a most recent systematic review.

Our results demonstrate that the incidence of PM among all intracranial metastases is 0.87% (95% CI 0.56, 1.18); it is 1.9% (95% CI 1.46, 2.34) among all autopsied cancer cases; it is 11.56% (95% CI 7.08, 16.04) among all breast cancer patients who had hypophysectomies and 12.83% (95% CI 10.5, 15.16) among all autopsied breast cancer patients. The fixed effect model showed that the incidence of PM in breast cancer patients group is significantly higher (p < 0.001) with an odds ratio of 6.71 (95% CI 4.24, 10.61). Breast and lung cancer are the most common primary cancer of PM with a percentage of 37.2 and 24.2 respectively. The next most common primary sites are prostate and kidney respectively, although the percentages for each are only about 5. Diabetes insipidus (DI) remains the most common symptom among all reported PM cases with a pooled incidence of 42.34% (95% CI 36.15, 48.53). Although not significant (χ(2) = 2.846, df = 1, p = 0.061), it is less common in the most recent reported cases which has a pooled incidence of 32.76% (95% CI 20.31, 45.21). DI is extremely rare in the reported PM cases from HCC (none of the eight cases presented with DI). The symptoms of anterior hypopituitarism (23.68 vs 39.66%, p = 0.015), visual deterioration (27.89 vs 41.38%, p = 0.039), cranial nerve palsies (21.58 vs 41.38%, p = 0.003) and headaches (15.79 vs 32.76%, p = 0.005) were reported significantly higher than previously described in the literature.

Pituitary metastasis is rare in patients with cancer, and the pituitary gland is an uncommonly involved location in patients with intracranial metastases. With advanced diagnostic imaging techniques and increased awareness about the manifestation of sellar lesions, the incidence of cranial nerve palsies and anterior pituitarism are higher than reported. This information may allow earlier diagnosis of PM.