Metastatic growth hormone secreting pituitary carcinoma treated with peptide receptor radionuclide therapy

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Introduction: Pituitary carcinoma (PC) is an extremely rare condition defined by the presence of adenohypophyseal neoplastic tissue outside the pituitary. Clinical experience regarding diagnosis, management and prognosis of PC is very limited. Growth hormone (GH) secreting PC is even rarer and represents a particular challenge to clinical practice. Therapeutic modalities utilized to treat PC include surgery, radiation, hormonal therapy, and cytotoxic drugs. Peptide Receptor Radionuclide Therapy (PRRT) is an emerging therapeutic modality that involves the targeted delivery of an ablative dose of radiolabelled somatostatin analog. PRRT has been applied to various neuroendocrine tumors and results in prolonged survival and enhanced quality of life. As yet, this therapy has not been applied to malignant pituitary tumors.

Aim(s): To present a case of GH secreting PC and suggest PRRT as an apparently effective therapeutic option.

Materials and methods: A 56-year-old female with a nine-year history of GH-secreting pituitary macroadenoma presented with worsening headache and marked acromegalic features. Surgical removal of the pituitary tumor was attempted twice, but GH and IGF-1 levels remained elevated and the pituitary mass re-expanded despite medical therapy with Octreotide and Cabergoline. The patient became severely debilitated with increasing fatigue, musculoskeletal pain, weight loss, and uncontrolled diabetes. Serum IGF-1 and GH levels were 135 nmol/L and 241 mcg/L, respectively. Whole body CT exam demonstrated numerous osteoblastic bone lesions. A CT-guided biopsy obtained from a bone lesion confirmed the diagnosis of metastatic GH-secreting PC. Octreoscan demonstrated numerous somatostatin avid lesions in the pituitary and the skeleton. Pasireotide therapy was attempted but not tolerated; Temozolamide was not available due to cost.

Conference: 7th Annual ENETSConcerence (2010)

Presenting Author: Kassem S

Authors: Kassem S, Gross D, Doviner V, Dresner-Pollak R,

Keywords: pituitary carcinoma, peptide receptor radionuclide therapy, acromegaly,