BACKGROUNDMediastinal lesions are uncommon and infrequent, encountered as mediastinal masses with wide histopathological spectrum which cause diagnostic difficulty to the clinicians and radiologists because of the variations of presenting symptoms, locati on and accessibility. Mediastinal lesions also pose difficulty in obtaining samples directly by Fine Needle Aspiration or Needle Core Biopsy technique, Ultra Sound/ Computed Tomography guided techniques aid in getting adequate material and to arrive at a definitive diagnosis in cases where resection of the lesion is not possible, and accessibility is poor. We wanted to present the spectrum of histopathological diagnosis of various mediastinal lesions both benign and malignant, encountered in this institution, a tertiary care center in India. METHODSThis is a retrospective study conducted from June 2015-December 2018 on Fine Needle Aspirations (FNA), Needle Core Biopsies (FNB) and surgically resected specimens of all mediastinal lesions sent to the Department of Pathology for histopathological examination. RESULTSA total of 43 cases of mediastinal lesions was taken into consideration. Out of these 43 cases, 17 (39.53%) were CT guided FNA, 5 (11.63%) CT guided FNBs and 21 (48.84%) were excised specimens. In 3 (6.97%) of these cases of FNA diagnosis was inconclusive and in 2 (4.65%) cases no opinion could be given as material was necrotic and inadequate. Of the total 43 cases 27 (62.8 %) cases were males and about 16 (37.2%) were female patients. M:F ratio was 1.7:1. Age distribution was between 04 -70 yrs. 4 (9.30%) of the cases were in paediatric age group (<16 yrs.) and 39 (90.60 %) were in adult age group (>1 6 yrs.). Mean age in adults was (47.7 yrs.). CONCLUSIONSThe present study emphasizes on the importance of awareness of various lesions that can occur in mediastinum, spectrum of histopathological variants and a definitive diagnosis in guiding the treating clinician to initiate the appropriate treatment at the earliest especially in cases of malignancies and non resectable lesions. Wherever necessary IHC should be done. In the present study, thymic lesions and lymphomas are the most common lesions encountered in adults (8 and 7 of the total 43 lesions). In paediatric age group, we encountered two thymic cysts and two lymphomas of which one was Hodgkin's and the other was Non-Hodgkin's lymphoma. HOW TO CITE THIS ARTICLE: Parasa GD, Remala KR, Turlapati SPV. Histopathological spectrum of mediastinal lesions in a tertiary care centre, Andhra Pradesh, India. BACKGROUND Mediastinal lesions are uncommon lesions which occur in the central portion of the thoracic cavity, limited by pleural cavities laterally, thoracic inlet superiorly, the diaphragm inferiorly and vertebral column posteriorly. Diagnosis of these lesions is a difficult task for clinicians, radiologists and pathologists because of its variable presentation clinically, inaccessibility and also due to histomorphological variations. Mediastinal masses present as space occupying masses situated in differ...