Pituitary metastasis of breast cancer mimicking IgG4-related hypophysitis

Abstract

IgG4-related hypophysitis, which is the pituitary gland inflammation caused by IgG4 positive lymphocytes, can affect cavernous sinus and orbital apex leading to developing cranial nerve related symptoms such as orbital apex syndrome (OAS). Here we report a case of hypopituitarism associated with OAS caused by pituitary metastasis of the breast cancer with elevated serum IgG4 level, who initially resembled to IgG4-related hypophysitis. Although this case had some features in common with igG4-related hypophysitis. The symptoms and pituitary enlargement were typical. However, steroid treatment did not improve her symptoms. Thus, we performed a tissue biopsy. Histopathologic examination of the hypophyseal tumor confirmed metastatic breast cancer in her pituitary. Pituitary metastatic tumor should be suspected if a case with OAS was once diagnosed as a cancer.

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

“…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.…”