Banded structures in the connective tissue of lymphomas, lymphadenitis, and thymomas

Hodgkin's disease accompanied with thymoma

An autopsy case of Hodgkin's disease accompanied with thymoma is reported. The patient died of acute interstitial pneumonitis 9 years after the development of lymphadenopathy. On post-mortem examination thymoma was recognized. We believe that the present case is a very rare Hodgkin's disease complicating thymoma. The occurrence of second neoplasia in Hodgkin's disease is also discussed.

The extracellular matrix in "sclerosing" follicular center cell lymphomas: an immunohistochemical and ultrastructural study

"Sclerosis" is frequently seen in follicular center cell (FCC) lymphomas. The mechanism of its deposition, as well as its composition and significance, are unknown. Several clinical studies have suggested that the course of these lymphomas is more indolent than that of lymphomas of the same histologic type without sclerosis. Nine immunologically characterized cleaved FCC lymphomas with sclerosis and 14 reactive lymph nodes with follicular hyperplasia were investigated by special staining methods, electron microscopy, and immunohistochemical studies with antibodies to types I, III, IV, and V collagen, laminin, and fibronectin. The sclerotic tissue in FCC lymphomas stained uniformly with periodic acid-Schiff (PAS) and Masson's stain, with the patterns ranging from delicate filamentous strands to dense doubly refractile bands. Ultrastructurally, the bands of connective tissue were continuous with the adventitia of vessels and composed of varying amounts of banded collagen (types I and III) admixed with filamentous and flocculent material. In all cases the neoplastic lymphocytes were separated from the extra-cellular matrix by fibroblasts and myofibroblasts with long cell processes. Immunohistochemical studies demonstrated intense staining of sclerotic bands with antibodies to fibronectin and type I collagen and, usually, weaker marking with antibodies to types III and V collagen. No significant staining of sclerotic bands was found with antibodies to type IV collagen or with laminin. Weak pericellular staining for type V collagen was present in eight of nine lymphomas and half of the control lymph nodes. These studies suggest that the increased amounts of extracellular matrix in cleaved FCC lymphomas are produced primarily by fibroblasts and myofibroblasts and represent predominantly fibronectin and types I, III, and V collagen. The composition of the sclerotic areas of FCC lymphomas is similar immunohistochemically to that of the capsule and trabeculae of reactive lymph nodes, which are also intimately associated with fibroblasts and myofibroblasts.

Diagnostic aspect of spindle-cell sarcomas by electron microscopy

Spindle-cell sarcomas in the somatic soft tissue and soft parts, including fibrosarcoma, leiomyosarcoma, malignant fibrous histiocytoma (MFH), and malignant schwannoma were examined by electron microscopy in order to delineate the most reliable cellular features for their diagnosis. Fibrosarcoma consisted largely of fibroblastic cells and leiomyosarcoma cells were packed in forming small cell groups with constant junctional complexes of nexus and zonula adherens types. MFH showed variable cellular features containing the cells with myofibroblastic and histiocytic differentiation. Malignant schwannoma was characterized by tumor cells having slender cytoplasmic processes with overlapping or interdigitation and thick basement membrane. These ultrastructural features were contributory to the differential diagnosis of the sarcomas examined.

Fibrous long spacing-like fibers in the bone marrow of myloproliferative disorder

Bone marrow obtained at autopsy from four cases of primary myelofibrosis and four cases of chronic myelogenous leukemia, was studied electron microscopically. In all the cases of primary myelofibrosis, the excess of collagen fibers in the bone marrow showed mostly about 2,000 A diameter and 1,000 A periodicity, i.e. fibrous long spacing (FLS)-like fibers. These FLS-like fibers were also seen in secondary myelofibrosis in three of the four cases of chronic myelogenous leukemia. These fibers were abundant around fibroblasts and small blood vessels. An apparent continuity between the dark bands of FLS-like fibers and the basement membrane material around small blood vessels was also revealed. Moreover, it was observed that these dark bands of FLS-like fibers contained acid mucopolysaccharides.

Distribution of fibrous long-spacing fibers in normal and pathological lymph nodes

The occurrence and distribution of fibrous long-spacing fibers (FLS) of lymph nodes in normal and pathological conditions have been examined by electron microscopy. The FLS can be easily identified by the characteristic broad cross bands with a 90 to 120 nm period. In normal lymph nodes, the FLS were most often found in the stalk of the valve projecting into the lymphatic sinus and in the perivascular matrix, and less frequently in the wall of the vein, in the sinus wall and in the stroma of the medulla at the hilus. In pathological conditions, a large number of FLS appeared in the hyalinous matrix of lymphocyte depletion type of Hodgkin's disease. These fibers were also observed in reticular matrices of lymphosarcoma and mixed cellularity type of Hodgkin's disease as well as in granulation tissues. It was noted that FLS appeared to be formed in the regions where abundant reticular fibers were laid down. Compared with the ultrastructural and histological findings in various lesions of lymph nodes, the possible mechanism and significance of FLS were discussed.

An electron microscopical study of the influence of different glycosaminoglycans on the fibrillogenesis of collagen type I and II in vitro

Proteoglycans (PG) and glycosaminoglycans (GAG) bind to collagen, and thus influence fibril formation. Polysaccharides interfere with the aggregation of collagen molecules and affect pattern formation. The morphological structure of type I and type II collagen was studied after adding different GAG to collagen solutions in test tubes in vitro. Electron microscopical investigations suggest that sulfated GAG change the aggregation behaviour of collagen molecules. Thus, the cross-striation pattern is changed. This effect seems to be based on the degree of sulfatation and not on the molecular weight of the GAG. Furthermore, GAG appear to have a stabilizing influence on the in vitro fibril formation.

Angioimmunoblastic lymphadenopathy. Fine structure of the lymph nodes by correction of light and electron microscopical findings

Angioimmunoblastic lymphadenopathy was studied prospectively in 5 patients by correlation of light and electron microscopy of biopsy material obtained from lymph nodes, prior to any substantial therapy. The fine structure of this lymphoproliferative disease revealed various patterns of cellular composition: there was a predominance of lymphocytes, immunoblasts, epithelioid or plasmacytoid cells or mixed cellularity in the lymph nodes. The conspicuous vascular changes consisted or arborization of postcapillary venules, a thickening of the basement membranes and swelling of the endothelial cells. The remarkable eosinophilic or acidophilic debris-like interstitial and pericapillar deposits showed filamentous finely dispersed material containing wide-spacing collagen fibers intermingled with normal collagen, but no fragments of disintegrated cells. Two of these 5 patients developed malignant lymphomas of the Hodgkin-type after 13 months, and of the Non-Hodgkin-type after 7 months. At the time of first biopsy, however, no characteristic alteration of the fine structure of the lymph nodes disclosed evolution towards malignancy.

Intracellular "fibrous long spacing" collagen in morbus dupuytren (Dupuytren's contracture)

Fine structural analysis of 21 surgically removed specimens of Morbus Dupuytren (Dupuytren's contracture) in the cells of the proliferative phase revealed spindle-shaped or round, periodic banded structures of 1--1.5 micron size. These intracellular structures are surrounded by trilaminar membranes of 45 A continuous with membranes of the endoplasmic reticulum. The periodic banded structures display a light-dark pattern of 750--900 A and resemble with respect to periodicity and general morphology "fibrous long spacing" collagen. To date, "fibrous long spacing" collagen in human tissue has only been observed in the extracellular space, both in normal and pathologic conditions. Its formal pathogenesis is discussed.

Fine structure of primary reticulum cell sacroma of the brain

An electron microscopic study was made on two cases of reticulum cell sarcoma (microglioma) of the brain. In both, the tumour was composed of several type of cells; cells with an undifferentiated appearance and cells with ultrastructural features of the reticulum cell and histiocyte. There seemed to be no significant difference in the fine structure between the tumour cells in reticulum cell sarcoma of the brain and extracerebral forms. The ultrastructures of a lymphosarcoma of the spinal epidural space was also examined and resembles that of such tumours occurring elsewhere in the body.