Pituitary carcinoma
Pituitary carcinoma is an exceptionally rare pituitary tumor, accounting for about 0.1% of all pituitary tumors, in which hormone hypersecretion is more common than hormone deficiency and mass effect on the optic chiasm or cavernous sinus can occur. Treatment follows standard pituitary tumor management with transsphenoidal surgery and hormone-specific medical therapy, escalating to radiation therapy and temozolomide chemotherapy when the tumor proves aggressive or resistant to surgical and medical treatment.
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What this article covers
- Overview
Definition: pituitary carcinoma is a pituitary tumor with malignant behavior, an exceptionally rare entity accounting for about 0.1% of all pituitary tumors.
- Epidemiology
Extraordinarily rare: pituitary carcinoma accounts for approximately 0.1% of all pituitary tumors, making it one of the least common entities in the differential of a sellar mass.
- Risk factors
A pre-existing functioning pituitary adenoma that proves aggressive or treatment-resistant: the best-documented example is a prolactinoma that continues to enlarge or secrete despite surgery and dopamine agonist therapy at tolerated doses.
- Pathophysiology
Pituitary carcinoma behaves, mechanistically, like other pituitary tumors with respect to local growth: an enlarging mass in the sella can compress the optic chiasm above (producing bitemporal…
- Clinical features
Symptoms and signs of hormone hypersecretion, which depend on the cell of origin: for a corticotroph-derived tumor, the features of Cushing syndrome (hypertension, diabetes mellitus, easy bruising…
- Differential diagnosis
Benign nonfunctioning or functioning pituitary adenoma: the far more common cause of a sellar mass, distinguished from carcinoma by a stable or surgically/medically controlled clinical course rather…
- Diagnosis
No single test on initial biopsy distinguishes pituitary carcinoma from an aggressive but benign adenoma; the diagnosis rests on the same pituitary hormone panel and MRI used for any pituitary tumor…
- Management
First, transsphenoidal resection of the tumor, the standard surgical approach for pituitary tumors through the nares or mouth, when the tumor is causing mass effect, visual deficits, or is otherwise amenable to surgery.
- Complications
Permanent visual field loss or blindness from prolonged or recurrent optic chiasm compression.
- Prognosis
Guarded, given the rarity and aggressive behavior of the disease: by definition, pituitary carcinoma has already shown a clinical course refractory to standard surgical and medical therapy by the time it is recognized.
- Prevention
Screen every newly diagnosed pituitary tumor for hypersecretion (prolactin, IGF-1, and Cushing disease evaluation if clinically suspected) regardless of symptoms, so that a functioning tumor is…
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Related articles
- Nonfunctioning pituitary adenoma
A nonfunctioning pituitary adenoma is a benign pituitary tumor, usually of gonadotroph origin, that does not secrete a clinically excessive hormone and presents through mass effect (visual field loss, headache) or hypopituitarism rather than a hypersecretory syndrome. Diagnosis requires excluding hormone excess and screening for hypopituitarism; treatment is observation for a small asymptomatic incidentaloma or transsphenoidal surgery for mass effect, apoplexy, or growth on follow-up.
- Prolactinoma
Prolactinoma is a prolactin-secreting pituitary adenoma, the most common functional pituitary tumor, presenting with hypogonadism and galactorrhea from prolactin excess or with headache and visual loss from mass effect in larger tumors. Diagnosis requires an elevated prolactin with a pituitary mass on dedicated MRI after excluding pregnancy, medication effect, and hypothyroidism, and first-line treatment is a dopamine agonist, most often cabergoline, which lowers prolactin and shrinks the tumor without surgery in most patients.
- Cushing disease
Cushing disease is hypercortisolism caused specifically by an ACTH-secreting pituitary adenoma, diagnosed after confirming ACTH-dependent Cushing syndrome and then localizing the pituitary source with MRI and, when needed, inferior petrosal sinus sampling. First-line treatment is transsphenoidal resection of the adenoma, with steroidogenesis inhibitors, radiotherapy, or bilateral adrenalectomy reserved for persistent or recurrent disease.