acid-phosphatase and Thymoma

Human thymuses, ranging in age from newborn to 62 years old, were studied enzyme histochemically. The thymic epithelial cells covering cortical surface and bordering vascular areas in the medulla were positive for 5'-nucleotidase, but not for other enzymes. The thymic epithelial cells composing Hassall's corpuscles were positive for acid phosphatase, esterases, beta-glucuronidase, and alkaline phosphatase, regardless of age, but totally negative for 5'-nucleotidase and ATPase. All enzymes examined except for beta-glucuronidase were demonstrated in some of the thymic epithelial cells scattered in the medulla, although the pattern of distribution and the degree of positivity were different by enzymes. These findings suggest that the thymic epithelial cells are composed of functionally heterogenous subpopulations. Acid phosphatase was demonstrated in thymocytes in both cortex and medulla, but 5'-nucleotidase and ATPase were observed in some thymocytes in the medulla of young thymus.

Topics: Acid Phosphatase; Adenosine Triphosphatases; Adolescent; Adult; Age Factors; Child; Child, Preschool; Esterases; Histocytochemistry; Humans; Infant; Middle Aged; Nucleotidases; Thymoma; Thymus Gland

We have examined a human thymoma, round-oval epithelial-type cell with moderate lymphocytic infiltration, whose major lymphocytic component (67%), unlike the minor one (33%), did not form rosettes with sheep red blood cells (E rosettes). However, these cells were of T-cell nature as indicated by the positive staining for both acid phosphatase and beta-glucuronidase, two well-accepted cytochemical markers for T cells. The non-E-rosetting lymphocytes expressed T 10, but not T 3 and T 6 antigens. Moreover, they lacked both peanut agglutinin and Fc-IgG receptors. On the contrary, 71 and 19% of the E-rosetting cells were PNA- and Fc-IgM-receptor positive, respectively. Furthermore, the non-E-rosetting cells were phytohemagglutinin unresponsive. The non-E-rosetting lymphocytes were larger (greater than 7 micron) than the E-rosetting cells and showed a different nuclear chromatin pattern. These immunological, cytochemical, and morphological features strikingly resemble those exhibited by cells (prothymocytes) normally found only in fetal thymus. On the basis of these findings we hypothesize the existence in this thymoma of a prothymocyte-like infiltration.

Topics: Acid Phosphatase; Cell Differentiation; Cell Membrane; Cell Transformation, Neoplastic; Child; Child, Preschool; Female; Glucuronidase; Hematopoietic Stem Cells; Humans; Infant; Lymphocyte Activation; Middle Aged; T-Lymphocytes; Thymoma; Thymus Neoplasms

Topics: Acid Phosphatase; Adenosine Triphosphatases; Alkaline Phosphatase; Autopsy; Electron Transport Complex IV; Enzymes; Esterases; Female; Histocytochemistry; Humans; Leucyl Aminopeptidase; Lysosomes; Microscopy, Electron; Middle Aged; Oxidoreductases; Sulfatases; Thymoma; Thymus Gland; Thymus Neoplasms