Pituitary carcinoma: A case report and discussion of potential value of combined use of Ga-68 DOTATATE and F-18 FDG PET/CT scan to better choose therapy.

Background: Pituitary carcinoma is extremely rare and carries a very poor prognosis. In most cases, apparently indolent tumors become malignant; however, there are no satisfactory biomarkers for predicting tumor behavior. Thus, scientific advances in the search for new biological markers, diagnostic methods, and therapies are needed to improve the prognosis of these patients.

Case Description: We report the case of a woman with initial diagnosis of nonfunctioning pituitary adenoma which evolved to carcinoma after 4 years. Diagnosis was confirmed after biopsy of metastatic pulmonary nodules, in which neoplastic cells were immunohistochemically positive for chromogranin, synaptotophysin, prolactin, and growth hormone. Investigation with conventional somatostatin receptor scintigraphy, positron emission tomography-computed tomography (PET-CT) with Ga-68 DOTATATE and F-18 fluorodeoxyglucose (FDG) are showed. During temozolomide therapy, our patient had severe pancytopenia resulting in death from generalized infection despite 10 days of intensive care.

Conclusion: The present case of an aggressive pituitary carcinoma rising from a typical adenoma illustrates the importance of developing new prognostic biomarkers in these cases. In addition to demonstrating a serious side effect with the use of temozolomide, our case report suggests that the combined use of Ga-68 DOTATATE and F-18 FDG PET-CT scan may scale somatostatin receptors vs. tumor aggressiveness, therefore, helping to better choose the therapy for aggressive pituitary tumors.