Pituitary carcinoma
Pituitary carcinoma is rare. However, an awareness of this diagnosis is important in patients with previously diagnosed pituitary adenoma who present with neurologic dysfunction or other signs of disseminated malignancy.
Constitutes less than 1% of patients with pituitary tumors 1) 2) 3).
Aggressive pituitary tumors are characterized by invasion of the parasellar region including the cavernous sinus, bone, and subarachnoid space of the suprasellar region. The diagnosis of pituitary carcinoma usually requires evidence of either intracranial or extracranial metastases 4).
Adrenocorticotropin secreting pituitary carcinoma is the most common secretory subtype which undergo malignant transformation 5) 6).
A 59-year-old male presented with a dural-based posterior fossa lesion. He had been diagnosed with a pituitary chromophobe adenoma 43 years earlier that was treated at the time with surgery and radiation therapy. A presumptive diagnosis of a radiation-induced meningioma was made and surgery was recommended. At surgery the tumour resembled a pituitary adenoma. Histopathology, laboratory findings, and the patient's medical history confirmed the final diagnosis of a prolactin-secreting pituitary carcinoma. To our knowledge, this is the longest reported interval between the pituitary adenoma and metastatic lesion diagnosis (43 years).
CONCLUSION: Management should be tailored to individual patient and may include a combination of treatments (surgery, radiation therapy, chemotherapy, and hormone-targeted therapy). Functionally active tumours may be monitored with hormone levels as tumour markers 7).