Endocrine Abstracts

Introduction: Pituitary malignancies include pituitary carcinomas and pituitary metastases. These malignancies are ver, rare and create important diagnostic and therapeutic challenges. This review presents an update on pituitary malignancies.

Methods: A systematic search of literature was conducted using the search terms pituitary carcinoma, pituitary metastasis, prevalence, management, and survival.

Results: Pituitary carcinomas are tumors of adenohypophyseal origin that have craniospinal and/or systemic metastases. They are denominated metastatic pituitary neuroendocrine tumors and represent around 0.1%-0.2% of all pituitary tumors. The affected patients are mainly males. The diagnosis of pituitary carcinomas is often delayed, and several cases are only diagnosed at autopsy. The clinical and biochemical features of pituitary carcinomas are usually similar to those of benign pituitary tumors. Most pituitary carcinomas are hormone-secreting tumors (mainly prolactin- and adrenocorticotropic hormone-secreting tumors) but some pituitary carcinomas develop in the setting of silent pituitary tumors. There are no well-established histopathologic, molecular, or genetic distinctions between benign pituitary tumors and pituitary carcinomas. The diagnosis of pituitary carcinomas cannot be made until metastases are identified. The metastases can be in the central nervous system (e.g., brain, spinal cord, dura, and leptomeninges) and/or distant organs (e.g., bone, liver, and lungs). The treatment of pituitary carcinomas includes surgery (e.g., gross total or subtotal resection), radiotherapy, and medical therapy (e.g., suppression of excess hormonal secretion, correction of hormonal deficiencies, chemotherapy, and immunotherapy). Although the prognosis is relatively poor, the survival of pituitary carcinomas has significantly improved since the introduction of temozolomide, a drug used as a first-line chemotherapy. Patients with metastases to the central nervous system have also a longer survival than those with distant organs metastases. Pituitary metastases account for approximately 1% of all pituitary tumors. They invade mainly the posterior lobe of the pituitary gland. Breast, lung, kidney, and prostate are the most common primary cancers. In several patients, the primary cancer remains unknown. Most cases are asymptomatic and often diagnosed at autopsy. Symptomatic patients present with diabetes insipidus, hypopituitarism associated with hyperprolactinemia, and visual impairment. The treatment of pituitary metastases includes surgery, radiotherapy, and medical therapy (e.g., correction of hormonal deficiencies, chemotherapy, and immunotherapy). The prognosis is poor. The median overall survival is approximately 1 year.

Conclusions: Pituitary carcinomas and pituitary metastases are rare malignancies that are difficult to diagnose and treat. They have poor prognosis. Most pituitary carcinomas are hormone-secreting tumors. The main cancers metastasizing to the pituitary gland are breast and lung cancers.