PATH-36. SYNCHRONOUS TTF-1-POSITIVE TUMORS AND PITUITARY ADENOMAS. ARE WE SENDING INSUFFICIENT TUMOR TISSUE FOR PATHOLOGY?

Abstract

Abstract BACKGROUND Tumors of the posterior pituitary are a distinct group of low-grade neoplasms arising from the sellar region. According to the most recent World Health Organization (WHO) guidelines, these tumors are grouped based on TTF-1 immunostain positivity. The coexistence of a posterior and anterior pituitary tumors is statistically extremely unlikely. OBJECTIVE In this study, we present a case of a 41-year-old woman suffering from Cushing syndrome with the presence of two pituitary masses on MRI. Also, the relevant literature is systematically reviewed. METHODS Two databases (PubMed and Google Scholar) and crossed references were systematically reviewed for TTF-1 pituitary tumors with coexisting pituitary adenoma or increased pituitary serum hormone levels. A literature review was performed according to PRISMA guidelines. Also, one patient from our institution is reported. Data regarding demographic features, type of anterior and posterior pituitary tumor, clinical features of the patients and lab results, MRI findings, and pathology results were extracted. RESULTS Seventeen retrospective case reports and case series were identified and included. Twenty-four patients were analyzed (including the reported case). The mean age was 46 ± 16 years, with a male-to-female ratio of 0.33:1. Pituicytomas and granular cell tumors were the only posterior pituitary tumors reported in 19 (79%) and 5 (21%) cases, respectively. There are only eight cases reported (including our patient) with a confirmed pituitary adenoma and a TTF-1 pituitary tumor (one GCT with GH-secreting adenoma, five pituicytoma with ACTH-secreting adenoma, one with GH-secreting adenoma and one with a null type adenoma). CONCLUSION We presented the eighth reported case of a TTF-1 pituitary tumor coexisting with a pituitary adenoma. We think that improving the amount of the tissue specimen available for pathology evaluation could increase the incidence of these very rare tumors.