Electron microscopy in the diagnosis of percutaneous fine needle aspiration specimens

Ewing's family of tumors involving structures related to the central nervous system: a review

This review consolidates information gleaned from several case reports and larger series on Ewing's sarcoma family of tumors (EFT) involving structures related to and found in the central nervous system (CNS). These tumors involve the skull, the spinal column, adjacent soft tissues, the meninges, and the brain. We have separated the cases by skull region and spinal column level, and we discuss the attendant differences in prognosis following treatment by neurosurgery, radiation, and chemotherapy. Light and electron microscopic features can be used to differentiate EFT from other small round blue cell tumors that involve the CNS (central primitive neuroectodermal tumor, lymphoma, etc.). Recent molecular and genetic findings in EFT provide new diagnostic methods. We conclude that EFT involving the CNS and adjacent structures is not so rare as previously stated and that the prognosis is more favorable, as a rule, than for the more common examples arising in the long bones and pelvis.

A novel system for assigning the mode of inheritance in mitochondrial disorders using cybrids and rhodamine 6G

When normal human cultured skin fibroblasts were treated with the fluorescent dye rhodamine 6G (R6G), there was a drastic reduction in numbers of intact mitochondria and electron transport chain enzyme activities, despite the fact that mitochondrial DNA (mtDNA) was still present in treated cells. We used this observation to develop a novel system for generating cybrids. When cultured skin fibroblast cells from a patient with the mitochondrial encephalopathy and ragged-red fibers (MERRF) syndrome harboring the A8344G mtDNA mutation and which showed a severe reduction in cytochrome c oxidase activity were treated with R6G and fused to enucleated HeLaCOT cells, the resulting cybrid clones showed recovery of cytochrome c oxidase activity, and were shown to have mtDNA derived solely from the HeLaCOT cell line. R6G has significant advantages over ethidium bromide in removing the mitochondrial elements from cultured cells, and the results reported here demonstrate that this strategy can be used to determine the origin of the genetic defect in patients with electron transport chain abnormalities.

Adenocarcinoma of the lung: electron microscopy of fine-needle aspiration biopsy specimens--a review of 73 cases

During a 10-yr period, 128 consecutive cases of pulmonary adenocarcinoma of varying differentiation were diagnosed with percutaneous fine-needle aspiration biopsy. Sediments from the needle and syringe washings with 3% glutaraldehyde were obtained and processed for electron microscopic evaluation in 73 cases. Our results showed three types of adenocarcinoma: 62 cases of nonciliated bronchiolar cell origin, 6 cases of bronchioloalveolar cell origin, and 3 cases of mucous cell origin. In addition, there was an example of combined adenosquamous carcinoma and an instance of amphicrine carcinoma. Our study provided a more precise definition of the cytologic diagnosis and insight into the heterogeneity of lung adenocarcinoma. However, prognostic differences between cell types of lung adenocarcinoma were not observed.

Utility of electron microscopy in the assessment of transthoracic needle lung biopsy specimens

RATIONALE AND OBJECTIVES

The authors determine the usefulness of electron microscopy (EM) in the workup of patients with certain intrathoracic masses undergoing transthoracic needle biopsy (TNB).

METHODS

Over a 4-year period, 1603 patients underwent TNB at our institution. Of these, 79 had EM examination of the aspirated material. The study is a retrospective review of this latter group. Previous use of EM for TNB had suggested that it may he helpful in those with pleural, chest wall, and mediastinal lesions. The 40 men and 39 women had pulmonary (n = 49), mediastinal (n = 17), pleural (n = 10), and chest wall (n = 3) lesions.

RESULTS

The adequate specimen rate was 59% (47 of 79) for light microscopy (LM) and 37% (29 of 79) for EM. Of the 28 patients with satisfactory specimens for both LM and EM, the correct diagnosis was obtained by LM 79% (22 of 28) and EM 96% (27 of 28) of the time. Electron microscopy was most helpful in patients with mediastinal (6 of 6 correct versus 3 of 6 for LM) and pleural (3 of 3 versus 1 of 3) lesions.

CONCLUSIONS

In specific circumstances, EM can be a very useful adjunct to LM in patients undergoing TNB. Problems with sample adequacy must be addressed.

Characterization of a new human bladder cancer cell line, UCRU-BL-28

A new human bladder cancer cell line, UCRU-BL-28 has been established and characterized from a relapsed, cisplatin resistant, grade II, stage T4 tumor. This line is tumorigenic in nude mice and reflects the pathology of the original tumor. The morphology, the expression of tumor-associated antigens and EGF receptors, and the ability to grow both in an anchorage independent manner and in the absence of serum is explored. The BL-28 line has 71-74XXY chromosomes, with del 5q, der(9) and i(19q). Further studies on the molecular basis of bladder cancer, chemosensitivity to cisplatin, growth factor production and tissue invasion are under way.

Diagnostic value of electron microscopy on paraffin-embedded cytologic material

Transmission electron microscopy (TEM) is an important adjuvant to light microscopy, but is underutilized in cytopathology because of technical obstacles. One should attempt to obtain properly fixed material for TEM whenever possible. If that is not available, TEM on the cell block requires no preplanning or additional needle passes, and avoids problems of inadequate tissue for diagnosis. However, cell blocks are often not examined because of the perception that their poor ultrastructural preservation precludes their utility. We describe our experience in performing TEM on cell blocks from 15 cytologic specimens. In 13 of 15 cases, the cell block material was adequate for ultrastructural evaluation, and it clarified or extended the diagnosis in seven of these cases. TEM is a useful adjuvant technique to cytodiagnosis and can be successfully performed on cell blocks when gluteraldehyde-fixed material is not available.

Comparative ultrastructure of needle aspiration biopsy and surgical resection specimens of lung tumors

Ultrastructural examination affords conclusive evidence for classification of lung tumors. Tissue properly fixed for electron microscopy is not available in many cases, however. Ultrastructural diagnosis of resected specimens obviously follows, rather than directs, the surgical treatment. Fine-needle aspiration (FNA) of lung masses is recommended as a means to obtain lung tumor tissue for electron microscopy. Nevertheless, no comparison has been made between ultrastructural information gained from aspiration specimens and resected specimens. Electron microscopy was performed on transthoracic FNA specimens of 10 lung tumors for which surgical resection was subsequently performed. Glutaraldehyde-fixed specimens from FNA and surgical resection were prepared for electron microscopy according to routine procedures. Fixation of the FNA specimens was equivalent or superior to that of the resected specimens in 9 of the cases. Three of the FNA specimens contained necrotic as well as viable tissue. Features essential for diagnosis such as desmosomes, junctions, neurosecretory granules, intermediate filaments, glycogen, lipid, mucin, and microvilli were identifiable in both FNA and resected specimens. FNA specimens therefore yield a representative sample of the ultrastructural features of lung tumors when adequate cellular material is obtained. Use of a coaxial needle sampling technique with immediate microscopic assessment reduces the likelihood of retrieving only blood or necrotic tissue in the electron microscopy specimens.

Electron microscopy of fine-needle aspiration biopsy from extragonadal germ cell tumors

We describe five cases of extragonadal germ cell tumor (EGCT) diagnosed by the electron microscope (EM) on cytological material. The clinical diagnosis was incorrect in all cases and EGCT was suspected in two cases; cytological diagnosis by light microscopy confirmed the presence of malignant tumor cells, but did not identify the cytotype/s correctly except in one case. Ultrasonography, laparoscopy, and autopsy (in case 3) excluded a primitive germ cell tumor (GCT). Histology confirmed the EM diagnosis in all cases. EM, even of scanty or necrotic cytological material, is particularly useful for mediastinal and retroperitoneal masses. In case of EGCT, EM can identify the different cytotypes and the different ultrastructural subcellular cytotypes and demonstrates a close relation between seminomatous and nonseminomatous GCT, which could influence their classification and prognosis.

Electron microscopy of fine-needle aspiration biopsy specimens: a brief review

The cellular sample obtained by fine-needle aspiration biopsy is usually small and therefore requires extreme care during processing for electron microscopy. The most significant technical problem is due to contamination of the sample by red blood cells, which tend to dilute the samples. Red blood cells in these samples may be removed prior to processing by either using Bovine serum albumin as a gradient or by filtration of the specimen by a nylon sieve. Experience at our institution with the use of electron microscopy for interpretation of fine-needle aspiration biopsy samples is briefly reviewed.

A quantitative comparison of light and electron microscopic diagnoses in specimens obtained by fine-needle aspiration biopsy

Because fine-needle aspiration biopsy (FNAB) is being increasingly used as a primary diagnostic tool, it is essential to obtain the maximum information from the aspirate. Electron microscopy is an adjunctive procedure that is readily applied to FNAB specimens. The value of electron microscopy to the cytopathologist was assessed by comparing the initial, tentative, or interim diagnosis based on light microscopic features with the diagnosis resulting from the ultrastructural characteristics of needle rinse material. Over a 3-year period, 279 FNAB specimens obtained under radiologic control were examined ultrastructurally; of these, 57 (20.4%) were considered inadequate specimens for diagnostic purposes. The remaining 222 FNAB specimens were segregated into four groups: 17 cases (7.7%) in which electron microscopy played a major role because the final diagnosis was unsuspected from light microscopy; 43 cases (19.4%) in which electron microscopy selected a specific diagnosis from a set of differential diagnoses or provided additional information that was clinically relevant; 45 cases (20.3%) in which additional diagnostic information was obtained by electron microscopy but was not clinically relevant; and 117 cases (52.6%) in which electron microscopy was not helpful because the light and electron microscopic diagnoses were the same. In this comparative study, electron microscopy provided a major contribution to the final cytologic diagnosis in 27.1% of the cases (groups 1 and 2). Descriptive examples illustrate how the architectural and cytologic features revealed by electron microscopy assist in establishing the final diagnosis. Examination of needle rinse specimens, particularly aspirates from lung and liver, indicates that most FNABs provide mini-surgical biopsy specimens that are well suited to ultrastructural examination.

Anemone cell tumor with neuroendocrine differentiation (presumed Merkel cell carcinoma)

A neuroendocrine tumor with ultrastructural "anemone cell" features in lymph nodes is reported. A primary tumor was not identified, but clinical and morphologic features suggested a metastatic Merkel cell carcinoma. The anemone cells were dissociated, lacked intercellular junctions, and contained cytoplasmic intermediate filament aggregates that immunohistochemically reacted with keratins, but they had only sparse neurosecretory granules. Where the tumor cells had infiltrated beyond the lymph nodes, however, they formed a trabecular pattern. A fine-needle aspirate from a later recurrence of the tumor lacked anemone cell features and was ultrastructurally typical of a Merkel cell carcinoma, with neurosecretory granules and intercellular junctions both being evident. The concept of anemone cell tumors and the morphologic variations determined by site are discussed.

Characterization of cell lines derived from a multiply aneuploid human bladder transitional-cell carcinoma, UCRU-BL-13

A series of cultured cell lines (designated UCRU-BL-13) has been established from different serial passages of a multiply aneuploid human bladder transitional-cell carcinoma xenografted in nude mice. Serial passage of the xenografts in vivo and of the cell lines in vitro was accompanied by shifts in the tumor ploidy, with dominance of different major peaks. Despite this, the expression of tumor markers remained constant, and consistent chromosomal markers were observed both in the 8th xenograft passage and in a subline in tissue culture established over a year apart. Chromosomal numbers reflected the predominant aneuploid peaks observed; consistent numerical and structural changes included a marker derived from chromosome 1, 8p-, -10, 11q+, and 17q+. The cell line derived from the initial xenograft comprised a mixture of transitional, adenocarcinoma and squamous carcinoma cells in early passage, but adenocarcinoma cells were absent from later passages. The lines expressed the B-blood-group antigen, histocompatibility antigens, receptors for transferrin and EGF, and reacted with a series of monoclonal antibodies (MAbs) directed to malignant human epithelial cell lines. These lines provide a model for studying the evolution of tumor heterogeneity and drug resistance in bladder carcinoma exhibiting multiple aneuploidy.