Challenges in primary neuroendocrine tumor identification

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Introduction: ACTH secreting neuroendocrine tumors can be a pituitary adenoma, an ectopic tumor, or very rarely - pituitary carcinoma. The identification of the primary neuroendocrine tumor can be challenging or even unsuccessful.

Aim(s): A complicated case of ACTH secreting neuroendocrine tumor is presented in this report.

Materials and methods: A 69-years old patient in 2015 was diagnosed with a pituitary adenoma. Transsphenoidal surgery was performed. The histological and immunohistochemical study of the primary tumor was uninformative because of necrosis. In 2017 patient developed ACTH dependent Cushing syndrome and inferior petrosal sinus sampling showed ACTH hypersecretion from the pituitary gland. Conventional radiotherapy was applied followed by the treatment with pasireotide. Due to the growth of the pituitary tumor remnant and significant hypercortisolism, in 2019 stereotactic gamma knife radiosurgery was performed. At the same time metastases in the vertebra and liver were diagnosed. Metastatic neuroendocrine carcinoma was confirmed in the liver biopsy, although there was not enough tissue to perform the immunohistochemical analysis for ACTH. Treatment with metyrapone along with chemotherapy was initiated.

Conference: 18th Annual ENETS Concerence (2021)

Presenting Author: Butkus M

Authors: Sereikaitė L, Butkus M, Jasinskaitė M, Žilaitienė B,

Keywords: cushing syndrome, metastatic neuroendocrine tumor, pituitary adenoma, pituitary carcinoma,