Seven cases of necrotizing lymphadenitis (NEL) including a pair of male siblings, a female suffering from non-bacterial meningitis, and two cases with the proliferation of monocytes and/or macrophages in the bone marrow are reported. This disease is clinically documented by the occurrence in young adults usually accompanied by painful cervical lymphadenopathy with fever and leukopenia (below 4,000/mm3). Morphological features were characterized by nuclear debris from degenerated lymphocytes and the appearance of blastoid cells and/or immunoblasts and macrophages. Ultrastructurally, tubular inclusions with a close relation to the endoplasmic reticulum were observed in various kinds of cells in the lesion. Immunohistochemical studies revealed that the ratio of helper/suppressor T-lymphocytes became low at the active stage and returned to normal range at the recovery stage. By immunohistochemical study it was confirmed that suppressor cells mainly corresponded to large transformed lymphocytes and/or immunoblasts and helper cells were degenerated by an unknown agent. Though the pathogenesis of NEL is still uncertain, it is suggested that T-lymphocytes are mainly involved during the course of the disease and lymphocytes show cellular debris or blastoid transformation. ACTA PATHOL.The most striking pathological feature is the enlargement of the lymph nodes revealing histologically monotonous cellular proliferation with minimal to rather extensive necrosis but lacking leukocytes. These foci are located sporadically in the paracortical area of the lymph nodes. The cause of this lymphadenitis is still unknown.A clinicopathological observation on 140 cases obtained from surgical pathology files and urban affiliated hospitals was reported briefly in a previous paper.3o In the present report, the authors will present 7 cases with an interesting course including a pair of male siblings, a female patient with non-bacterial meningitis, and two other patients showing the proliferation of monocytes and/or macrophages in bone marrow. An attempt was made to characterize the subset of T-lymphocytes in the lymph node and peripheral blood using monoclonal antibodies. Matevials and MethodsMaterials from 7 patients with necrotizing lymphadenitis were obtained from affiliated hospitals by surgical biopsy. For light microscopy, all of the fresh tissue specimens were fixed in 15-20% formalin and embedded in paraffin. Serial sections of 4 um in thickness were made and stained with hematoxylin and eosin (H.E.), periodic acid-Schiff (PAS), methylgreen pyronin and Pap silver impregnation. Imprints from the cut-surface of the lymph nodes in Cases 5 and 6 were stained with May-Giemsa. An immunofluorescent study for parainfluenza type 3 in Cases 1, 2, and 3 were carried out. Immunoperoxidase studies using paraffin sections were carried out for lysozyme, &lo0 protein, and carcinoembryonic antigen (CEA). For electron microscopy, the lymph nodes and buffy coats of Cases 1, 3, and 4 were cut into small pieces and fixed in glutaraldehyde and postfixed...

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To clarify the histogenesis of B cell chronic lymphocytic leukemia (BCLL), clinicopathological and immunophenotypic studies were performed using a large panel of monoclonal antibodies on 12 cases with BCLL including three caes with prolymphocytic/chronic lymphocytic leukemia (CLL/PL). Immunophenotypically, CD19 and CD20 were positive for all cases of this series and CD5, CD21, CD22, CD23, CD25, CD38, Leu‐8, KB‐61, and bcl‐2 protein were expressed in variable proportion from case to case. CD10, however, did not react. No alkaline phosphatase (ALP) positive cases were found. The phenotype of BCLL was similar to that of B cells of the mantle zone (MZ) of secondary follicle in the lymph node. It is therefore postulated that the neoplastic cells of BCLL in these cases might be derived from B cells of the MZ. Moreover, the cells possibly originated from the lymphocytes located in the inner layer of the MZ, since ALP+ B cells are usually observed in the outer layer of the MZ. The pseudofollicular (PF) pattern was observed in four biopsied lymph nodes among five cases tested, but no such a pattern in an aspiration clot of bone marrow. These four cases consisted of three cases with CLL and a case with CLL/PL. The immunohistochemical study showed that there were many proliferating cells showing Ki‐67+ in the PF area of the lymph nodes. In these cases, leukemic cells might have developed from the PF area of the lymph node.