ABSTRACT
Background: The microscopic structure of spleen is variable depending on the developmental stage of the organ, and the age and immune status of the individual. The aim of the investigation was to study the microscopic structure of human spleen in different age groups, starting from a six month old foetus up to the eighth decade of life. Methods: Seventy formalin fixed human spleens obtained postmortem, were included in the study. They were classified into different age groups, in both sexes, for a detailed study of the microscopic details. Results: The white pulp of spleen showed peri-arteriolar lymphatic sheath (PALS) and lymphatic follicles. The corona or mantle zone and the germinal centre were discernible in many of the Malpighian bodies. The marginal zone separating the red pulp from the white pulp also could be clearly demarcated. The marginal sinus and peri-follicular zone could be seen in some sections only. The capsule thickness, trabecular network, cellularity of white pulp and red pulp, the connective tissue framework seen in the red pulp etc., showed variations in the different age groups. Conclusion: The microscopic structure of spleen varies in different age groups, with the PALS and the white pulp showing scanty cellularity in the six month foetus, and almost uniform cellularity in all areas of spleen at full term. Thereafter the follicles showed increase in its cellularity up to the third decade, and then seemed becoming progressively atrophic. Further studies are required on age related changes in the cellular architecture of this organ correlating with its functions.