Small Round Cell Neoplasms: Can Electron Microscopy and Immunohistochemical Studies Accurately Classify Them?

Abstract

The answer to the question posed in the title, "Small Round Cell Neoplasms: Can Electron Microscopy and Immunohistochemical Studies Accurately Classify Them?", is obviously "yes"; but a qualified yes--generally yes, perhaps with expertise usually yes, but never just plain yes. Some cases certainly will defy the best attempts even of the most expert in the application of these "special" techniques. And embarrassing as it may be for those of us infatuated with the latest technology to admit, it is with the difficult case especially that old-fashioned technology so often must be depended upon. In his excellent recent appraisal of the role of a variety of special techniques in this application, Triche offers the following comment: "Overall, electron microscopy is probably the most universally useful of all diagnostic techniques other than light microscopy in round cell tumors." The data from our studies certainly point to the same conclusion. With each of the tumors, electron microscopy demonstrated itself to be more reliable than immunohistochemistry. Electron microscopy offers not only greater sensitivity and specificity, but also greater versatility. Immunohistochemistry allows hypothesis testing only. Electron microscopy, on the other hand, can provide answers even when the right questions are not being asked. For example, if a particular small round cell tumor under investigation happens in actuality to represent something other than the neuroblastoma which it is being considered (e.g., a granulocytic sarcoma, liposarcoma, Wilm's tumor, etc.), electron microscopy can reveal this fact, but a neuron-specific enolase stain cannot. Parenthetically, it should also be said that electron microscopy has proven particularly well suited to the examination of fine-needle aspiration specimens. The two spare many patients in our institution the need for a major operative procedure to establish a secure tissue diagnosis. Immunohistochemistry does have a role to play but it is, at least in our opinion, clearly secondary to that of electron microscopy. The concept of replacing electron microscopy with a battery of immunostains has often been advocated as an economic measure, but this argument begins quickly to lose its weight as the number stains included in the battery is increased to cover the diagnostic possibilities. Giving consideration to the capriciousness of some of these stains, there exists with this also an increasing possibility of a spurious or misinterpreted result leading to an errant diagnosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Differentiating Lymphoblastic Lymphoma and Ewing's Sarcoma: Lymphocyte Markers and Gene Rearrangement

“…The presence of intracytoplasmic glycogen as determined by the periodic acidSchiff stain with diastase digestion is sometimes used to distinguish ES from lymphoma. However, glycogen can be found in lymphoma (19). Immunohistochemistry is potentially the most reliable diagnostic aid in the differential diagnosis of ES and lymphoma.…”

Peripheral Neuroblastomas in Two Dogs

“…1,4,7,10 Special stains (Giemsa for secretory granules; Cresyl violet and toluidine blue for Nissl substance; Cahal's stain for glial fibers; Hortega's silver carbonate stain for neurofibrils; Masson-Fontana silver stain for reticulin) of formalin-fixed neoplastic tissues were negative for diagnostic features of these neoplasms. Electron microscopy on sections from both abdominal masses was inconclusive because of autolysis; dense-core secretory granules or neurofilaments, typical of neuroblastoma cell, 5,6 were not observed.…”

“…[1][2][3][4][5]8,11,14,15 We report the diagnosis, treatment, and management of toxoplasmosis in wallabies on an exotic animal farm.…”

“…These results were compatible with neuroblastoma. 5,8,10 Neoplasms of neural or neuroendocrine origin are classified according to the degree of differentiation of the transformed cell. Neuroblastomas are tumors of the most primitive or immature cell type (i.e., the neuroblast).…”

Comparação entre a citopatologia por biopsia com agulha fina e a histopatologia no diagnóstico das neoplasias cutâneas e subcutâneas de cães

“…Dentre estes tumores estão o linfoma maligno, o histiocitoma, o mastocitoma pouco diferenciado, o plasmocitoma, e o melanoma amelanótico (Goldschmidt & Hendrick 2002). Uma alternativa para o diagnóstico desse tipo de neoplasias seria a utilização da técnica de imunohistoquímica (Mierau et al 1985, Ohsie et al 2008.…”