Histol Histopath (1990) 5: 299-304 Histology and Histopathology The ruptured spleen. A histological, morphometrical and immunohistochemical study H. Barnard, E.J. Dreef and J.H.J.M. van Krieken Department of Pathology, University Hospital Leiden, The Netherlands Summary. A traumatically ruptured spleen is regarded as a proper control in many histological and immunolo- gical studies on the human spleen. This paper compares spleens that ruptured due to trauma and spleens which were removed during surgery in patients without splenic pathology. Based on a histological, morphometrical, and immunohistochemcial description of the control spleens it is shown that the traumatically ruptured spleens contain alterations in the lymphoid tissue. The amount of white pulp is increased due to a larger amount of CD4- positive lymphocytes. Furthermore there are alterations in lymphocyte populations in the different splenic compartments. It is concluded that spleens that rupture may be predisposed due to immunological stimulation. Key words: Spleen, Rupture, Histology, Immunohisto- chemistry, Morphometry Introduction The spleen may rupture due to trauma or ccspontaneously~~ , i.e. without apparent trauma (Mitchell and Morris, 1983). Traumatically ruptured spleens are mostly regarded as normal. Although it is diffucult to define what an adequate trauma is, there are several disorders which may facilitate spontaneous splenic rupture; infectious mononucleosis is one of the most well known examples (Andrews et al., 1980; Rogers and Shah, 1980; Armitage et al., 1981; Berlin et al., 1982: Adouin and Diebold, 1983; Bennett et al., 1984; Caruso and Hall, 1984; Chamberlain et a]., 1984; Cochrane, 1984; Doehrmann and Scheele, 1984: Cooperberg et al., 1985; Fallingborg et al., 1985; Mirchadani et al., 1985; Birenbaum et al., 1986; Majewski and Stahlknecht, 1986). Offprint requests to: J.H.J.M. van Krieken, MD, PhD, Laboratory of Pathology, University of Leiden, PO Box 9603, 2300RC Leiden, The Netherlands A previous study has shown that there is an increase in the amount of white pulp in traumatically ruptured spleens compared to spleens which were removed inci- dentally during abdominal surgery without apparent splenic pathology (van Krieken et al., 1983). This leads to the suggestion that in many cases of so-called traumatic rupture of the spleen there might be a predisposing factor, such as, for instance, a viral infection. In order to investigate the lymphoid tissue in ruptured spleens in more detail, it was compared with the lymphoid tissue of spleens without splenic pathology using morphological. immunohistochemical, and mor- phometrical methods. Materials and methods All spleens removed were processed immediately. which included methylmethacrylate embedding and freezing of tissue blocks as described before (van Krieken et al., 1983, 1986). From ruptured spleen blocks were taken from macroscopical normal -tissue at a distance from the rupture. Extensively crushed specimens were excluded from study. For this study ten spleens with minor rupture due to trauma were available and compared to the ten most recent spleens removed during cancer surgery (mainly partial gastrectomy for early gastric cancer), and to nine spleens removed during surgery for non-malignant disease without splenic pathology. The latter group consists mainly of cases of highly selective vagotomy or implantation of aortic prothesis. lmmunohistochemistry Cryostat sections were stained using a three-step immunoperoxidase technique with the following antibodies: Leu 4 (CD3), Leu 3 (CD4): Leu 1 (CD5). Leu 2 (CD8), Leu 14 (CD22) all Becton & Dickinson; B l (CD20), B2 (CD21), both Orthoclone; Tul (CD23), Biotest.