Delineating the Spectrum of Pituitary Adenoma Based on the WHO 2017 Classification.

BACKGROUND: The WHO 2017 classification of endocrine tumors incorporates lineage-specific transcription factors (TF) and hormone expression for the classification of pituitary adenoma (PA). There is paucity of reports describing the spectrum of PA based on this classification. OBJECTIVE: The aim of this study was to delineate the spectrum of PA based on WHO 2017 classification of endocrine tumors. MATERIALS AND METHODS: PA diagnosed in the year 2018 were studied. H and E and hormonal immunohistochemistry (IHC) for GH, PRL, ACTH, TSH, FSH, LH, CK, T-Pit and MIB-1 were performed and the results were analyzed. RESULTS: The cohort included 88 cases. M: F ratio was 2:1. Clinically, 22 (25%) were functional and 66 (75%) were non-functional adenomas. Amongst the clinically functional adenomas, GH secreting adenomas were the commonest (68%). Majority (83%) of non-functional adenomas were hormone positive with gonadotroph adenomas being the commonest (72.7%). Eleven (12.5%) PA were clinically and hormonally silent. Three of these showed intense nuclear T-Pit positivity, classifying them under silent corticotroph adenoma. Lineage of the remaining eight adenomas remained undetermined, since, IHC for Pit-1 and SF-1 was not performed. The aggressive adenomas identified by IHC included sparsely granulated somatotroph adenoma, Crooke cell adenoma, silent corticotroph adenoma, densely granulated lactotroph adenoma in men and constituted 17% of the PA. Four (4/88) cases were clinically invasive. CONCLUSION: A large majority of PA including aggressive adenomas can be identified by IHC. Addition of T-Pit helped to identify silent corticotroph adenoma. Pit -1 and SF-1 TF would help identify plurihormonal Pit-1 PA and null cell adenomas.

Spectrum of Germ Cell Tumor (GCT): 5 Years' Experience in a Tertiary Care Center and Utility of OCT4 as a Diagnostic Adjunct.

Germ cell tumors (GCT) are an intriguing group of neoplasm having myriad clinical and morphological presentation. More and more transcription factors are being evaluated for identification of same. To study the spectrum of GCTs in a tertiary care center and the use of a stem cell marker OCT4 as a diagnostic adjunct, a retrospective 5-year (2008-2013) study was carried out. Immunohistochemistry (IHC) with OCT4 was performed on all cases and IHC for α feto protein (AFP), CD30, and epithelial membrane antigen (EMA) as per requirement. Cohort included 73 cases (23 males and 50 females). Testicular and ovarian GCTs accounted for 95.83% and 35.71% respectively. In males, seminoma was the commonest (34.78%) followed by mixed GCT (26%). 17.85% of ovarian GCTs were malignant mostly constituted by dysgerminoma (18%). Benign mature cystic teratoma (MCT) constituted 50% of ovarian GCTs. OCT4 immunoexpression was seen in all cases of seminoma/dysgerminoma, embryonal carcinoma, immature teratoma, and seminomatous/embryomatous component of mixed GCTs. Pure yolk sac tumor (YST) and MCT were consistently negative. OCT4 was especially helpful in identification of mixed GCT. A panel of immunohistochemical markers would be a more ideal way to identify and clarify the components because correct identification of the components is important for therapeutic intervention and prognostication. OCT4 being a primordial germ cell marker predicts aggressive behavior and targeted therapy against this should be investigated.