An Ultrastructural Morphometric and Immunohistochemical Analysis of Cutaneous Lymphomas and Benign Lymphocytic Infiltrates of Skin

Abstract

Our combined ultrastructural, immunohistochemical, histologic, and clinical studies over the past five years have allowed us to compile diagnostic criteria useful in the evaluation of cutaneous lymphomas. As a group, mycosis fungoides (MF) patients could be distinguished from those with benign disorders of skin using ultrastructural morphometry (mean form factor and perimeter values), but with some overlap between groups. Another approach, the ultrastructural histogram method, however, clearly separated MF patients from patients with chronic dermatitis. Immunohistochemistry was useful in distinguishing cases of cutaneous peripheral T-cell lymphoma from MF cases on the basis of the occurrence of "novel phenotypes." Neoplastic T-cell infiltrates of skin can usually be distinguished from benign polyclonal T-cell infiltrates by the presence of one T-cell subset to the exclusion of others. Patients with convoluted B-cell lymphomas could also be distinguished from MF patients using ultrastructural morphometric dual parameter analysis. The diagnostic complexity of several cutaneous T-cell lymphoma cases is illustrated. We have emphasized in this study the strength of combining quantitative electron microscopy, immunohistochemistry, and histology in the diagnostic workup of cutaneous lymphomas. This integrative approach may be necessary to assure a definitive diagnosis in difficult cases.

Diagnostic value of combining immunostaining for CD3 and nuclear morphometry in mycosis fungoides

“…Other authors have used combinations of morphology and immunostaining, mostly by electron microscopy, in order to achieve better morphological details or to ensure that the cells analysed corresponded to T-lymphocytes 12 – 14. Although important for scientific purposes, the use of ultramicroscopy and immunoelectron microscopy is by no means feasible in routine diagnosis.…”

Polymerase Chain Reaction Analysis of Immunoglobulin Gene Rearrangement in Cutaneous Lymphoid Hyperplasias

“…2,3 Immunophenotyping with leukocyte monoclonal antibodies is helpful to detect monoclonal B-cell proliferation by light chain restriction. 4,5 However, a discrete monotypic B-cell infiltrate can be masked by a dense reactive infiltrate. 6 Molecular analysis of lymphoid gene rearrangements by Southern blot analysis has proved to be useful for the detection of clonal populations and the determination of the lineage of lymphomas.…”

Non Lymphoblastic T Cell Lymphomas with Prevalent Skin Involvement Different from Mycosis Fungoides or Sézary’s Syndrome

“…Indeed, the proliferation was either nodular (periadnexal or perivascular) or diffuse, the upper part of the derm (Grenzzone) remained in tact except in case 6 and no epidermotropism was noted. However, Payne et al [30] recently reported non-MF/SS peripher al T cell lymphomas with epidermotropism.…”

“…Polymorphism of the proliferation, polyclonal staining of in tracellular immunoglobulins and blood eosinophilia have a limited value as criteria of pseudolymphomas since there is sometimes an exuberant host response in non-MF/SS Tcell lymphomas (case 1) [13]. Similar ma ture Tcell phenotype may be present both in pseudolymphomas and Tcell lymphomas [48,49] although the immunological characteristics of benign infiltrates are usually more heterogeneous [30], The T cell receptor gene study may thereby be a major tool for early differentiation between Tcell lymphomas and pseudolymphomas [13].…”