Morphologic and morphometric study of the two main cell lineages involved in mycosis fungoides: the lymphoid cells and the Langerhans cells

Fine-needle aspiration biopsy of Langerhans histiocytosis (histiocytosis-X)

A series of 14 fine-needle aspiration biopsies (FNAB) from histologically proven cases of histiocytosis-x (Hx) were reviewed. The smears revealed a variable mixture of Langerhans cells, eosinophils, macrophages, polymorphonuclear cells, and giant cells. Based on the predominant cells present, the cases were further categorized as Langerhans cell predominant (nine cases), eosinophil predominant (two cases), and macrophage predominant (three cases). Langerhans cells were usually polygonal without significant evidence of phagocytosis and frequently contained indented nuclei. In three cases, several Langerhans cells showed prominent dendritic processes. Electron microscopy in 10 cases revealed Langerhans cells with varying degrees of morphologic differentiation. All cases studied revealed Birbeck granules. These findings indicate that FNAB may be an effective technique for diagnosing Hx.

A multidisciplinary approach to the diagnosis of cutaneous T-cell lymphomas

The cutaneous T-cell lymphomas (CTCLs) comprise a spectrum of non-Hodgkin lymphomas with a predilection for the skin. This heterogeneous group of CTCLs include the prototypic CTCL mycosis fungoides (MF) and the recently described Ki-1+ lymphomas. MF is notoriously difficult to diagnose in its early stages. The histologic appearance of early MF is indistinguishable from that of chronic dermatitis. The limitations of light microscopy in the diagnosis of the CTCLs have led to the development of other diagnostic laboratory techniques. The best approach to the diagnosis of the CTCLs is a multidisciplinary one and should include ultrastructural morphometry, immunophenotyping, immunogenotyping, and histologic evaluation whenever possible. It is the purpose of this overview to point out the strengths and weaknesses of each of these techniques and, together with clinical input, to provide a comprehensive and rational approach to patient care.

Ultrastructural characteristics of the contact zones between Langerhans cells and lymphocytes

The present work was carried out to look for the ultrastructural substrate of the contact zones between Langerhans cells and lymphocytes. A high resolution electron microscopic analysis of the contact zones between Langerhans cells and lymphocytes was performed. The material used for this study was obtained from experimental contact dermatitis in mice, and human cervical squamous carcinoma and mycosis fungoides. Three types of cell-cell binding were found. Type I is a junction-like structure characterized by the presence of intercellular bridges. It is suggested that this contact might represent a fixation mechanism between the two cells. Type II is characterized by a glycocalyx-glycocalyx continuity. An immunological function--recognition and antigen presentation--is proposed for this type of contact. Type III is a septilaminar tight contact area which seems to be a gap junction. It is suggested that all these types of physical contact might be the morphological expression of interaction between antigen presenting cells and lymphocytes.

Ultrastructural characteristics of the interdigitating dendritic cell in dermatopathic lymphadenopathy of mycosis fungoides patients

The ultrastructure of interdigitating dendritic cells in dermatopathic lymphadenopathy from patients with mycosis fungoides was investigated. The most remarkable findings were: a marked hypertrophy of the smooth endoplasmic reticulum with a peculiar concentric arrangements of the cisternae around lipid droplets, an abundance of cytoplasmic lipid droplets and the presence of paranuclear chromatoid-like bodies. It is suggested that these ultrastructural features may correspond to some unknown functional capability of the interdigitating dendritic cell.

Immunohistochemical study of epidermal Langerhans cells and dermal dendritic cells in benign and malignant skin lesions characterized by a dermal lymphoid infiltrate consisting either of B-cells or T-cells

Skin biopsies from 43 patients with a rather dense dermal lymphoid infiltrate of either inflammatory or neoplastic nature have been investigated. We studied the number, distribution and immunophenotype of epidermal Langerhans cells and dermal dendritic cells. As previously reported, differences in epidermal Langerhans cell and dermal dendritic cell numbers between skin biopsies with a B-cell infiltrate and skin biopsies with a T-cell infiltrate were found, dendritic cells being more numerous in the latter. The main finding of this study was an uneven distribution of epidermal Langerhans cells and dermal dendritic cells in skin biopsies with a T-cell infiltrate: in skin lesions with an inflammatory lymphoid infiltrate, small clusters of epidermal and dermal dendritic cells admixed with T-lymphocytes (predominantly T-helper/inducer cells) and small blood vessels were present at areas of exocytosis. In skin lesions with a neoplastic lymphoid infiltrate larger, more loosely arranged aggregates of dendritic cells and T-cells were seen. These cell aggregations composed of activated (inflammatory or neoplastic) T-cells and dendritic cells may represent the cutaneous homologue of the secondary T-nodule in the lymph node. Both types of cell aggregates may correspond to the dendritic cell-T cell clusters observed in in vitro induced immune responses.

The widespread distribution of Langerhans cells in pathologic tissues: an ultrastructural and immunohistochemical study

Ultrastructural and/or immunohistochemical analysis of approximately 500 specimens revealed widespread distribution of Langerhans cells in pathologic specimens. More than half of the tissue specimens were from patients with a variety of pulmonary diseases. In all specimens in which Langerhans cells were identified ultrastructurally, they were also identified by an immunoperoxidase technique for the visualization of S-100 protein; the latter technique also revealed the dendritic nature of these cells. Langerhans cells were present in 80 to 93 per cent of 66 pulmonary adenocarcinomas and 17 per cent of squamous cell lung cancers; they were not observed in neuroendocrine lung carcinomas or mesotheliomas. They were also observed in benign inflammatory conditions of the lung of several types and in a variety of other malignant neoplasms and disease processes. The Langerhans cells in these tissues varied from few to many. They were most numerous in bronchioloalveolar cell carcinoma, sometimes appearing almost as frequently as tumor cells, and rare in some benign pulmonary conditions and other tumors. The function of Langerhans cells in these conditions is unknown, but they may have an immunologic function, such as antigen processing and presentation to T lymphocytes.

Langerhans cells in verruciform xanthomas: an immunoperoxidase study of 10 oral cases

Ten oral verruciform xanthomas were studied using an immunoperoxidase stain for S-100 protein. All cases exhibited positively stained dendritic cells among the mononuclear inflammatory cell infiltrate at the base of the lesions and to a lesser extent among the "foam cells". The foam cells were, however, negative for S-100 staining. We suggest that, based on these findings, verruciform xanthomas belong to a new category of "non-X histiocytoses" in which the presence of Langerhans cells suggests an immunologic pathogenesis.

Nuclear morphologic and morphometric analyses of large noncleaved cell and immunoblastic non-Hodgkin's lymphomas

Both morphologically and immunologically, non-Hodgkin's lymphoma (NHL) of the large cell type has been shown to be a heterogeneous category. However, the homogeneity of the nuclear parameters, particularly size and condensed chromatin organization, used to classify this subtype of NHL has not been investigated. In fact, objective morphologic techniques have not been systematically applied to verify the segregation of NHL on the basis of nuclear parameters, a concept common to all current classification systems. In this study morphometric image analysis was used to compare the nuclei in 20 specimens from NHLs of the large cell type with those in mantle zone and germinal center lymphocytes from lymph nodes with reactive hyperplasia. Results of the assessment of mean nuclear area in large cell lymphomas revealed that this class is also heterogeneous, with some of the specimens having a nuclear size in the upper range of that for normal small lymphocytes. In addition, in only a few of these specimens was the mean nuclear area within the range of that for fully transformed germinal center lymphocytes. The majority of large cell lymphomas have a nuclear size more characteristic of partially transformed lymphocytes in germinal centers. In addition to indicating inconsistencies in the current diagnostic criteria used in NHL classifications, the results indicate reasons for interobserver variations in clinicopathologic trials; the validity of nuclear size as a prognostic indicator and the biologic basis for classifying NHL as a reflection of normal lymphocyte transformation are also questioned. In terms of patient management, the classifications of NHL currently used require objective reappraisal.

Langerhans cells in squamous exocervical carcinoma: a quantitative and ultrastructural study

The gross morphology, density, distribution, and ultrastructure of the Langerhans cell (LC) in the human exocervix in cases of cervical intraepithelial neoplasia (CIN) and incipient carcinoma were investigated. Two zinc-iodide-osmium (ZIO) procedures were applied to epithelial sheets and to tissue sections for light and electron microscopy. The ZIO methods as well as conventional electron microscopy revealed the presence of LCs in CIN, in the invasive prongs, and in the lymphoid infiltrate of the chorion. The epithelial sheets demonstrated a LC density 3.5 times higher than we have previously reported for the normal exocervix. The region around the external os displayed the highest LC density and the most advanced grades of CIN. The LCs were classified into six types according to the number of processes and secondary branches. The most ramified types were more abundant in the neoplastic exocervix than in the normal exocervix. The LC in all locations of the exocervix with carcinoma showed hypertrophy of the rough and smooth endoplasmic reticula and a large number of filaments. The RER displayed dilated cisternae containing electron-dense material. Specialized contacts between LCs and lymphocytes were an outstanding finding. These findings suggest that the LC might play an important role in the neoplastic process.

Langerhans cells in granulomatous syphilis

In a case of granulomatous syphilis (transitional state between early and late syphilis), several Langerhans cells (LC) were present in the basal and medial part of the epidermis. Evidence of LC activation was given by the presence of many Langerhans granules, vesicles, a large Golgi apparatus and, sometimes, Golgi complexes. In some LC, signs of degeneration were visible. Langerhans granules surrounded by cytoplasmic material were present in the intercellular space of the epidermis. Apposition of lymphocytes to LC in the dermal space supports the role of LC in immunologic mechanisms. This was further confirmed by signs of phagocytosis in LC. The interaction of LC with intra-epidermal microorganisms (as, for instance, the Treponema pallidum) might be important in the development of the epidermotropic infiltration. This mainly consists of lymphocytes, which sometimes form a pseudolymphoma. A correlation between LC and granuloma formation is suggested.