Abstract : Background: The thymus is the lymphoid organ of greatest importance. It is a structurally separated
lobules through the tissue of the connective septa. That lobule has a cortex and a medulla in it. Many
studies of this organ related to the histology of early fetuses are focused on animals. The present study
focuses on certain features relating to the histogenesis of the thymus and adolescent fetuses.
Materials and Methods: In the present study, 50 normal human stillborn/aborted fetuses and one is 15
years thymus gland in adolescent was studied from 18 to 35 weeks were examined. The acquired fetuses
were set in formalin of 10 per cent. They have been exposed to dissection after correct fixation. The
specimens acquired had been processed through a well-known paraffin block making process. Sections
were taken with haematoxylin & eosin, and painted. The stained sections had been tested using 40x and
100x optical magnifications and pictures taken under light microscopy.
Result: Compared to its CRL, the gland’s dimension has changed. Compared to gestational age, the mass
of the gland and fetuses was. It has been demonstrated capsule, septae, cortex, medulla, blood vessel,
lymphocytes, reticular epithelial cells, adipose cells, and the corpuscle of Hassall.
Conclusion: Thymus gland involution, pondered in its anatomy and histology, will serve as a basis for
becoming conscious of pathological conditions.Within the first 18 weeks of gestation, all structural changes
viz. cortico-medullary differentiation, lobulation, and maturity of the hassall’s corpuscles happened.
Keywords: Fetuses thymus, Haematoxylin eosin.