A case of pheochromocytoma with a marked decrease in catecholamine levels after rupture in which a good outcome was achieved by elective surgery.

Changes in imaging findings and hormone levels before and after pheochromocytoma rupture, as well as detailed histopathology of resected tumors, have rarely been reported. A 52-year-old woman developed hypertension and diabetes mellitus in 2014, but despite treatment with antihypertensive and hypoglycemic drugs, good control was not achieved. On April 2, 2016, the patient started to have headaches and palpitations, and on April 6, she visited our hospital. Plain computed tomography (CT) of the abdomen showed a 4-cm, isodense mass in the left adrenal gland, and the patient was hospitalized for further examination. Because the patient had hypertension, tachycardia, and hyperglycemia on admission, therapies for those were started. Catecholamine levels were markedly elevated. However, after the patient developed left flank pain on Day 4, antihypertensive and insulin therapies were no longer required. Plain CT then showed heterogeneous high density areas in the left adrenal mass. On Day 7, 3 meta-iodobenzylguanidine scintigraphy showed no abnormal uptake. On Day 8, contrast CT showed low density areas within the left adrenal tumor and contrast enhancement of the tumor margins, and catecholamine levels were markedly decreased. Elective left adrenal tumor resection was performed on Day 49. The capsule of the resected tumor was ruptured. Histopathology showed widespread hemorrhagic necrosis and viable cell components in the tumor margins. Positive chromogranin A staining of the tumor cells confirmed a diagnosis of pheochromocytoma. This patient displayed remarkable changes in imaging findings and hormone levels before and after pheochromocytoma rupture. Pheochromocytoma rupture and hemorrhagic necrosis were confirmed histopathologically.