Histopatholgical spectrum of thymic neoplasms: twelve-year experience at a referral hospital in north India.

This study was undertaken to determine the histopathological spectrum and clinical profile of thymic neoplasms at a tertiary referral care centre. A total of 96 thymectomy specimens were received during the study period (1992-2004), which consisted of 54 neoplasms and 42 benign lesions. Among the neoplasms there were 48 thymic epithelial tumors, 3 thymolipomas and 3 thymic carcinoids. The former comprised of 36 male (75%) and 12 female patients (25%) ranging in age from 2-70 years (mean 37 years). Among paraneoplastic syndromes in thymic epithelial tumours, 27 out of 48 (56.25%) cases were associated with myasthenia gravis and one case was associated with pure red cell aplasia. The most frequent histological subtype was cortical thymoma (43.24%) followed by predominantly cortical (24.32%) and well-differentiated thymic carcinoma (18.92%). On staging, all cases of mixed and predominantly cortical subtype were stage 1 whereas one medullary and 2 cortical thymomas and 4 well differentiated thymic carcinoma (WDTC) showed pleural and pericardial invasion (stage III). This study has revealed that half of thymic epithelial tumours presented as myasthenia gravis. The cortical thymoma was the most frequently encountered histologic subtype and most commonly associated with myasthenia gravis.