Pituitary Metastasis Presenting With Central Diabetes Insipidus and Panhypopituitarism

Abstract

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A case of pituitary metastasis discovered when diabetes insipidus developed in a patient 20 years after breast cancer treatment

“…In pituitary metastasis, a mass forms in the pituitary stalk from the intrasellar region, causing thickening of the pituitary stalk. When it progresses, it invades the cavernous sinus and other surrounding areas or progresses superiorly to the diaphragma sellae and may present as a dumbbell shape with a constriction in the diaphragma sellae [1 , 4 , 9] . On MRI, hyperintensity disappears on T1WI of the posterior pituitary, isointensity with the pituitary is seen on T1WI and T2WI, and enhancement is seen on contrast-enhanced MRI [1 , 4 , 5 , 9] .…”

“…When it progresses, it invades the cavernous sinus and other surrounding areas or progresses superiorly to the diaphragma sellae and may present as a dumbbell shape with a constriction in the diaphragma sellae [1 , 4 , 9] . On MRI, hyperintensity disappears on T1WI of the posterior pituitary, isointensity with the pituitary is seen on T1WI and T2WI, and enhancement is seen on contrast-enhanced MRI [1 , 4 , 5 , 9] . Pituitary metastasis is readily suspected if there is clear invasion into the surrounding tissue, but other findings are not specific to pituitary metastasis.…”

“…Histopathologic diagnosis is the definitive diagnosis for pituitary metastasis, but clinically it can be suspected from the existence of a primary tumor or the existence of metastases in 2 or more places other than the pituitary, and is diagnosed with patient characteristics [4] . In adults with no history of granulomatous disease, cancer, or other conditions that are a cause of posterior pituitary lesions, lymphocytic infundibuloneurohypophysitis heads the list, based on its incidence, in the differential diagnosis when diabetes insipidus and space-occupying lesions of the posterior pituitary are present [7 , 9] .…”

“…Pituitary metastasis of breast cancer accounts for 6%-8% of cases [5] . In 4 patients in whom pituitary metastasis was diagnosed more than 10 years after the diagnosis of the primary disease, all were cases of breast cancer [ [9] , [11] , [12] , [13] ]. Of them, metastases at other sites had been found in three patients before the pituitary metastasis was discovered, or when a full body examination was performed at the same time as the pituitary metastasis and metastases were found at other sites [9 , 11 , 13] .…”

“…In 4 patients in whom pituitary metastasis was diagnosed more than 10 years after the diagnosis of the primary disease, all were cases of breast cancer [ [9] , [11] , [12] , [13] ]. Of them, metastases at other sites had been found in three patients before the pituitary metastasis was discovered, or when a full body examination was performed at the same time as the pituitary metastasis and metastases were found at other sites [9 , 11 , 13] . In the present patient as well, the metastasis was from ER-positive breast cancer, and lung metastasis was suspected from multiple pulmonary nodules on CT performed after the pituitary biopsy.…”