Giant cell-rich extrapleural solitary fibrous tumor: Cytological findings and differential diagnosis of a rare neoplasm.

Extrapleural solitary fibrous tumor (ESFT) is a rare neoplasm with a variable biological behavior that may occur almost everywhere in the body, as it has been reported in head and neck, back, retroperitoneum, inguinal region and more. The diagnosis of ESFT may be challenging, especially in case of its morphological rare variants such as giant cell-rich ESFT. Fine-needle aspiration cytology (FNAC) is a rapid, poorly invasive, safe diagnostic technique, which is recently proving useful for the preoperative diagnosis of mesenchymal neoplasms. Herein we report a case of a FNAC diagnosis of giant cell-rich ESFT, focusing on its morphological and immunocytochemical characteristics, and showing how cytology may be an effective tool in the preoperative diagnosis of mesenchymal neoplasms, allowing the correct surgical management of the patient.

Amyloid in bone marrow smears of patients affected by multiple myeloma.

Systemic AL amyloidosis is associated with nearly 15% of cases of multiple myeloma, but data on the frequency and significance of amyloid deposits in the bone marrow of patients affected by multiple myeloma without clinical signs of systemic amyloidosis are scanty. Bone marrow smears of 166 unselected patients affected by multiple myeloma (126 at diagnosis and 40 after treatment) were stained with Congo red and studied by transmission and birefringence microscopy. Both focal and diffuse storages were considered positive. Overall, 67 patients were positive and 99 were negative to Congo red and apple-green birefringence. In particular, 51 of the 126 patients studied at diagnosis and 16 of the 40 patients with advanced disease were positive. Seventeen patients were reassessed after a mean follow-up of 32 months (range: 6-91): disappearance of amyloid deposits was verified in three cases, all responsive to bortezomib-based regimens. The preliminary data available suggest that amyloid deposition in the marrow of myeloma patients is frequent, as it can be traced in nearly 40% of cases. We failed to find correlations between bone marrow amyloid deposits and immunoglobulin type, disease stage, plasma cells percentage, hemoglobin, calcium, creatinine, albumin, or beta(2)microglobulin. Significantly higher incidence of moderate/severe peripheral neuropathy was found in patients with marrow amyloid exposed to potentially neurotoxic antineoplastic agents. Further studies and prolonged follow-up are needed to validate our findings and to define possible prognostic aspects.

Fine needle aspiration cytology and flow cytometry immunophenotyping of non-Hodgkin lymphoma: can we do better?

OBJECTIVE: To evaluate the diagnostic efficiency of fine needle aspiration cytology/flow cytometry (FNAC/FC) in the diagnosis and classification of non-Hodgkin lymphoma (NHL) in a series of 446 cases and to compare the results with those of previous experiences to evaluate whether there had been an improvement in FNAC/FC diagnostic accuracy. METHODS: FNAC/FC was used to analyse 446 cases of benign reactive hyperplasia (BRH), NHL and NHL relapse (rNHL) in 362 lymph nodes and 84 extranodal lesions. When a diagnosis of NHL was reached, a classification was attempted combining FC data and cytological features. Sensitivity, specificity and positive and negative predictive values (PPV and NPV) of FNAC/FC in the diagnosis and classification of NHL were calculated and compared with those available in the literature. RESULTS: FNAC/FC provided a diagnosis of NHL and rNHL in 245 cases and of BRH in 188 cases. In nine cases, the diagnosis was 'suggestive of NHL' (sNHL) and in four cases was inadequate. Histology and clinical follow-up confirmed 102 cases of NHL and detected one false positive. In 18 cases of BRH diagnosed by FNAC/FC, histological examination revealed 14 BRH and four NHL (false negatives). All nine cases diagnosed as sNHL were confirmed by histology. Including sNHL cases as false negatives, statistical analysis showed 94.9% sensitivity, 99.4% specificity, 99.6% PPV and 93.4% NPV in the diagnosis of NHL. A specific subtype was diagnosed in 125 cases and confirmed in 67 of 70 cases that had histological biopsies. Statistical analysis did not demonstrate significant improvements between the present series and previous studies either in diagnosis or in classification of NHL. CONCLUSIONS: FNAC/FC is a fundamental tool in the diagnosis and classification of NHL but the exiguity of diagnostic material and other technical and clinical limitations will probably continue to limit further improvement of the technique.

Fine needle cytology and flow cytometry of ectopic cervical thymoma: a case report.

BACKGROUND: A case of ectopic cervical thymoma (ECT) in which fine needle cytology (FNC) and flow cytometry (FC) have orientated the cytologic diagnosis, is described. CASE: A 57-year-old woman underwent FNC of a right latero-cervical nodule. The smear showed a dispersed lymphoid-cell population; therefore, a second FNC was used for FC and to prepare a cell block. Smears were highly cellular. Cells were medium or large sized, with scanty cytoplasm and nuclei with dispersed chromatin; large cells showed evident nucleoli. Immunohistochemistry on additional smears were positive for CD45RO and Ki67 in most of the cells, and negative for CK pan, CD20, thyreoglobulin and calcitonin. FC showed the following phenotype: CD2/CD3/CD7 = 67%, CD10 = 61%, CD4/CD8 = 62%. CD19 and light chains were not expressed. A diagnosis of T-cell lymphoid proliferation was made and ECT was suggested; histological diagnosis was cervical ectopic benign type B1 thymoma. CONCLUSION: FC may support the FNC diagnosis of ECT because of the specific phenotype of lymphoid cells showing the profile of "polyclonal" (CD2/CD3/CD7+) and thymic T-cells (CD10+, CD4/CD6+). FNC and FC may suggest the diagnosis of ECT even in the absence of detectable epithelial cells.

The continuing role of breast fine-needle aspiration biopsy after the introduction of the IAC Yokohama System For Reporting Breast Fine Needle Aspiration Biopsy Cytopathology.

BACKGROUND: Ultrasound-guided fine-needle aspiration biopsy (FNAB) (US-guided FNAB) is a rapid and cost-effective procedure for the diagnosis of breast lesions. Our Institution has a long tradition in breast FNAB performed by cytopathologists; recently we adopted both US guidance and a five-tiered classification system similar to that proposed by the International Academy of Cytology (IAC). The aim of this study was to demonstrate the continuing role of US-guided FNAB in the diagnosis of breast lesions, despite the growing adoption of core-needle biopsy (CNB). METHODS: The laboratory information database system was searched to obtain the breast FNAB diagnostic reports recorded from 2010 to 2017 and classified using a five-tiered Classification System; each entry was matched with the available histology. RESULTS: A total of 4624 breast FNAB samples were retrieved. Of these, 1745/4624 cases (37.7%) had histological follow-ups. The risk of malignancy (ROM) was 4.9% for benign, 20.7% for atypical, 78.7% for suspicious of malignancy, and 98.8% for malignant. When the atypical category was evaluated as a negative index, the positive predictive value was 93.73%, and the negative predictive value was 90.78%, reaching an overall diagnostic accuracy of 92.82%. CONCLUSIONS: The IAC Yokohama System for Reporting Breast FNAB Cytopathology clearly identifies different diagnostic categories with increasing ROM. Most of the FNAB samples were classified as benign or malignant (65.3%), warranting prompt management for these patients. Moreover, the inclusion of the atypical category as a low-risk indeterminate category avoided overtreatment of benign lesions. Thus, despite the well-established merits of CNB, US-guided FNAB still represents a cost-effective and rapid nonoperative diagnostic approach.

Exploring the Inter-observer Agreement Among the Members of the Italian Consensus for the Classification and Reporting of Thyroid Cytology.

Classification schemes for reporting thyroid cytology of fine needle aspiration (FNA) of thyroid nodules are largely used in clinical practice, but the level of inter-observer agreement among cytopathologists is poorly acknowledged. The present study aimed to explore the inter-observer agreement among the experienced authors of the 2014 Italian Consensus for Classification and Reporting of Thyroid Cytology (ICCRTC). A stratified randomization was performed in order to obtain a sample homogeneously distributed and representative of all ICCRTC classes. Four high-experience raters were randomly selected among the extensors of the Italian consensus. They independently reviewed 60 FNA samples blindly of the initial cytological report and clinical features. Their overall agreement was evaluated according to Fleiss' kappa. The overall inter-observer agreement was moderate (κ 0.46). Specifically, a good agreement was found when the samples were consistent for malignancy (TIR5) or were not adequate for diagnosis (TIR1) (κ 0.67 and κ 0.73, respectively). A moderate agreement was present for suspicious-for-malignant category (TIR4), and a fair agreement was recorded in the two intermediate ones (TIR3A and TIR3B) (κ 0.36 and κ 0.35, respectively). For clinical purposes, the agreement was good (κ 0.74) in differentiating cases with surgical indication (TIR4/TIR5) from those in which surgery is not essential or requires limited extension (TIR3B/TIR3A/TIR2). In conclusion, the present study confirms the reliability of ICCRTC. These data represent a reference for cytopathologists using this system and are useful for the practice of clinicians and surgeons.

UbcH10 expression in human lymphomas.

AIMS: The UbcH10 ubiquitin-conjugating enzyme plays a key role in regulating mitosis completion. We have previously reported that UbcH10 overexpression is associated with aggressive thyroid, ovarian and breast carcinomas. The aim of this study was to investigate UbcH10 expression in human lymphomas. METHODS AND RESULTS: Cell lines and tissue samples of Hodgkin's lymphoma (HL) and of non-Hodgkin's lymphoma (NHL) were screened for UbcH10 expression at transcriptional and translational levels. UbcH10 expression was related to the grade of malignancy. In fact, it was low in indolent tumours and high in a variety of HL and NHL cell lines and in aggressive lymphomas. It was highest in Burkitt's lymphoma, as shown by quantitative real-time polymerase chain reaction and by tissue microarray immunohistochemistry. Flow cytometry of cell lines confirmed that UbcH10 expression is cell-cycle dependent, steadily increasing in S phase, peaking in G(2)/M phase and dramatically decreasing in G(0)/G(1) phases. We also showed that UbcH10 plays a relevant role in lymphoid cell proliferation, since blocking of its synthesis by RNA interference inhibited cell growth. CONCLUSIONS: Taken together, these results indicate that UbcH10 is a novel lymphoid proliferation marker encompassing the cell cycle window associated with exit from mitosis. Its overexpression in aggressive lymphomas suggests that UbcH10 could be a therapeutic target in this setting.

Galectin-3-expression analysis in the surgical selection of follicular thyroid nodules with indeterminate fine-needle aspiration cytology: a prospective multicentre study.

BACKGROUND: In the USA, about 30 200 well-differentiated thyroid carcinomas were diagnosed in 2007, but the prevalence of thyroid nodules is much higher (about 5% of the adult population). Unfortunately, the preoperative characterisation of follicular thyroid nodules is still a challenge, and many benign lesions, which remain indeterminate after fine-needle aspiration (FNA) cytology are referred to surgery. About 85% of these thyroid nodules are classified as benign at final histology. We aimed to assess the diagnostic effect of galectin-3 expression analysis in distinguishing preoperatively benign from malignant follicular thyroid nodules when FNA findings were indeterminate. METHODS: 544 patients were enrolled between June 1, 2003, and Aug 30, 2006. We used a purified monoclonal antibody to galectin-3, a biotin-free immunocytohistochemical assay, and a morphological and phenotypic analysis of FNA-derived cell-block preparations. Galectin-3-expression analysis was applied preoperatively on 465 follicular thyroid proliferations that were candidates for surgery, and its diagnostic accuracy was compared with the final histology. FINDINGS: 31 patients were excluded because they had small galectin-3-negative thyroid nodules; we did not have data for 47 patients; and one patient with an oncocytic nodule was excluded. 331 (71%) of the assessable 465 preoperative thyroid FNA samples did not express galectin-3. 280 (85%) of these galectin-3-negative lesions were classified as benign at final histology. Galectin-3 expression was detected, instead, in 134 of 465 (29%) thyroid proliferations, 101 (75%) of which were confirmed as malignant. The overall sensitivity of the galectin-3 test was 78% (95% CI 74-82) and specificity was 93% (90-95). Estimated positive predictive value was 82% (79-86) and negative predictive value was 91% (88-93). 381 (88%) of 432 patients with follicular thyroid nodules who were referred for thyroidectomy were correctly classified preoperatively by use of the galectin-3 test. However, 29 (22%) of 130 cancers were missed by the galectin-3 method. INTERPRETATION: Our findings show that if the option of surgery was based theoretically on galectin-3 expression alone, only 134 thyroid operations would have been done in 465 patients; therefore a large proportion (71%) of unnecessary thyroid surgical procedures could be avoided, although a number of galectin-3-negative cancers could be potentially missed. The galectin-3 test proposed here does not replace conventional FNA cytology, but represents a complementary diagnostic method for those follicular nodules that remain indeterminate.

Cytological and molecular diagnosis of solid variant of papillary thyroid carcinoma: a case report.

Papillary thyroid carcinoma (PTC) composed by predominant solid areas is diagnosed as a distinct variant on histological samples. Here we present a case of PTC recognized preoperatively by fine needle cytology as a solid variant. This diagnosis was made by combining cytology with the detection of the BRAFVK600-1E mutation, the molecular hallmark of the solid variant of PTC. Histological and molecular evaluation of the surgical specimen confirmed this pre-operative diagnosis. Thus combining cytology to BRAF molecular analysis is useful to refine the cytological diagnosis of this variant also on FNC specimens.

Primary intramuscular infestation of Echinococcus granulosus misdiagnosed as a soft tissue tumor: a case report.

BACKGROUND: The occurrence of a primary intramuscular infestation of Echinococcus granulosus is extremely rare. CASE: A 70-year-old woman with primary skeletal muscle hydatidosis initially presented with a soft tissue mass. Clinical and radiologic examination revealed a huge cystic mass in the right quadriceps muscle without any visceral organ involvement. Since the differential diagnosis included a soft tissue tumor, fine needle aspiration cytology was performed, and a diagnosis of hydatid disease was made. CONCLUSION: This very rare case of primary intramuscular infestation of E granulosus was clinically misdiagnosed as a soft tissue tumor. Hydatid disease, albeit rare, should be considered in the differential diagnosis of a soft tissue mass.

Pulmonary langerhans cell histiocytosis (histiocytosis X) on bronchoalveolar lavage: a report of 2 cases.

BACKGROUND: Pulmonary Langerhans cell histiocytosis (PLCH) is an interstitial lung disease characterized by bilateral nodular and cystic lesions. Clinically it seems to be a reactive process related to cigarette smoking. CASES: In 2 cases of PLCH, cytologic and immunocytochemical evaluation of bronchoalveolar lavage (BAL) fluid was successfully used for the diagnosis of PLCH. Two heavy smokers complained of fever, cough and debilitation. Serologic and hematologic values were normal. In both cases radiography and computed tomography (CT) were similar, showing multiple bilateral nodular or cystic lesions in the middle and upper lung zones. Cytospins obtained from BAL were Papanicolaou and May-Grünwald-Giemsa stained; others were immunostained with cytokeratin cocktail, CD1a and S-100. Cytospins showed a monomorphous and dispersed cell population consisting ofmononucleated or binucleated and occasionally multinucleated histiocytes. Single cells showed wide, well-defined, acidophilic cytoplasm and oval or kidney-shaped, vesicular nuclei with irregular shapes, evident nucleoli and frequent grooves and indentations. Immunocytochemical staining showed diffuse cytoplasmic positivity for S-100 and CD1a and negativity for cytokeratin; only the few cylindrical cells present in the cytospins were positive for cytokeratin. In both cases the cytologic diagnosis of PLCH was confirmed by subsequent CT and clinical follow-up. CONCLUSION: Cytologic and immunocytochemical evaluation of BAL fluid permits a definitive diagnosis of PLCH. This cytologic diagnosis is clinically relevant because it permits surgical biopsy to be bypassed and allows waiting for a possible spontaneous or pharmacologic resolution.

Detection of BRAF mutation in thyroid papillary carcinomas by mutant allele-specific PCR amplification (MASA).

OBJECTIVE: The somatic point mutation in the BRAF gene, which results in a valine-to-glutamate substitution at residue 600 (BRAF(V600E)), is an ideal hallmark of papillary thyroid carcinoma (PTC). However, its prevalence is varyingly reported in different studies, and its expression in the follicular variant PTC is controversial, reducing its potential usefulness as diagnostic marker. DESIGN AND METHODS: We developed an assay based on mutant allele-specific PCR amplification (MASA) to detect BRAF mutation. We compared the sensitivity of MASA, single-strand conformation polymorphism (SSCP) and direct DNA sequencing of PCR products. Then, we used MASA 78 to analyze 78 archival thyroid tissues, including normal samples, follicular adenomas, follicular carcinomas and PTC. RESULTS: The MASA assay proved to be a more sensitive method than SSCP and DNA sequencing of PCR products. BRAF mutation was found by MASA in 19/43 (44.2%) of PTC, including 14/31 (45.2%) classic forms and 5/12 (41.7%) follicular variants. No mutations of BRAF were detected in the normal thyroid tissues, nor in follicular adenomas or follicular carcinomas. No correlation was found between BRAF mutation and clinicopathologic features nor with recurrence during a postoperative follow-up period of 4-11 years. BRAF(V600E) significantly correlated with absence of node metastasis. CONCLUSIONS: BRAF(V600E) is present in PTC, both in the classic form and in follicular variant with similar prevalence. No correlation was found between BRAF mutation and aggressive clinical behavior. MASA-PCR proved to be a specific, sensitive and reliable method to detect BRAF T1799A in DNA extracted from different sources, including cytologic samples obtained either fresh or from archival glass slides. We propose this method as a useful tool to improve accuracy of preoperative diagnosis identifying PTC from biopsies with indeterminate cytologic findings.

Critical role of cyclin D3 in TSH-dependent growth of thyrocytes and in hyperproliferative diseases of the thyroid gland.

We report that cyclin D3 is rate limiting for G1 progression in thyroid follicular cells and that its constitutive upregulation by chronic stimulation of the TSH/cAMP pathway plays a role in human and experimental hyperproliferative diseases of the thyroid gland. These conclusions are supported by in vitro and in vivo studies. In rat thyrocytes (PC Cl 3 cells), cyclin D3 expression is enhanced in response to activation of the TSH/cAMP pathway. Interference with the expression of G1 cyclins (in particular cyclin D3) by the antisense methodology strongly reduced TSH-dependent proliferation of PC Cl 3 cells, indicating that proper progression through G1 requires cyclin D3. Accordingly, PC Cl 3 cells engineered to overexpress cyclin D3 (PC-D3 cells) show enhanced growth rate and elude hormone-dependence and contact inhibition. Using an animal experimental model of thyroid stimulation, we demonstrate that cyclin D3 is a key mediator of TSH-dependent proliferation of thyroid follicular cells also in vivo. Cyclin D3 protein levels were higher in the thyrocytes from glands of propylthiouracil-treated rats compared with control animals. The increase in cyclin D3 expression occurred after the propylthiouracil-induced increase in TSH levels and preceded the burst of cell proliferation. Finally, we found that cyclin D3 protein is expressed in a fraction of human goiters but it is strongly overexpressed in most follicular adenomas.

Aurora B overexpression associates with the thyroid carcinoma undifferentiated phenotype and is required for thyroid carcinoma cell proliferation.

Alterations in chromosome number (aneuploidy) are common in human neoplasias. Loss of mitotic regulation is believed to induce aneuploidy in cancer cells and act as a driving force during the malignant progression. The serine/theronine protein kinases of aurora family genes play a critical role in the regulation of key cell cycle processes. Aurora B mediates chromosome segregation by ensuring orientation of sister chromatids and overexpression of Aurora B in diploid human cells NHDF (normal human diploid fibroblast) induces multinuclearity. We analyzed Aurora B expression in human thyroid carcinomas. Cell lines originating from different histotypes showed an increase in Aurora B expression. Immunohistochemical analysis of archive samples showed a high expression of Aurora B in anaplastic thyroid carcinomas; conversely, Aurora B expression was not detectable in normal thyroid tissue. Real-time PCR analysis confirmed a strong expression of Aurora B in anaplastic thyroid carcinomas. The block of Aurora B expression induced by RNA interference or by using an inhibitor of Aurora kinase activity significantly reduced the growth of thyroid anaplastic carcinoma cells.

p27Kip1 is expressed in proliferating cells in its form phosphorylated on threonine 187.

BACKGROUND: G1/S cell cycle progression requires p27Kip1 (p27) proteolysis, which is triggered by its phosphorylation on threonine (Thr) 187. Since its levels are abundant in quiescent and scarce in cycling cells, p27 is an approved marker for quiescent cells, extensively used in histopathology and cancer research. METHODS: However here we showed that by using a specific phosphorylation site (pThr187) antibody, p27 is detectable also in proliferative compartments of normal, dysplastic and neoplastic tissues. RESULTS: In fact, whereas un-phosphorylated p27 and MIB-1 showed a significant inverse correlation (Spearman R = -0.55; p < 0,001), pThr187-p27 was positively and significantly correlated with MIB-1 expression (Spearman R = 0.88; p < 0,001). Thus proliferating cells only stain for pThr187-p27, whereas they are un-reactive with the regular p27 antibodies. However increasing the sensitivity of the immunocytochemistry (ICH) by the use of an ultra sensitive detection system based on tiramide signal amplification, simultaneous expression and colocalisation of both forms of p27 was shown in proliferating compartments nuclei by double immunofluorescence and laser scanning confocal microscopy studies. CONCLUSION: Overall, our data suggest that p27 expression also occurs in proliferating cells compartments and the combined use of both regular and phospho- p27 antibodies is suggested.

Metaplastic breast carcinoma on fine-needle cytology samples: a report of three cases.

Metaplastic breast carcinoma (MBC) may have a varied presentation on fine-needle cytology samples. We herewith describe three cases of MBC found in our series. One of these cases showed a peculiar mixture of malignant ductal, apocrine type, and squamous epithelial cells with fascicles of spindle cells with variable degree of atypia and was diagnosed as metaplastic carcinoma of the carcino-sarcomatous type. The other two lesions were characterized by an abundant chondroid extracellular matrix to which were variably admixed carcinomatous and chondroid-type cells, with variable degree of atypia. Both these latter cases were defined as matrix-producing metaplastic carcinomas. Because of the various presentation of MBC on fine-needle cytology samples and the possible influence of needle "sampling" on the cytological specimen, the spectrum of differential diagnoses to be considered may encompass a number of benign and malignant entities, like keratinous subareolar cysts, malignant fibroepithelial lesions with myxo-chondroid stroma, and true sarcomas of the breast, with cartilaginous metaplasia. It is the Authors' feeling that, with optimal samples, the cytomorphological findings of this rare variant of breast carcinoma permit its accurate pre-operative diagnosis.

Fine needle cytology of endometriosis: experience with 10 cases.

OBJECTIVE: To evaluate whether commonly used cytologic criteria for the diagnosis of endometriosis are sufficiently specific, to assess the possible role of special methods in the differential diagnosis and to assess the clinical meaning and drawbacks of a cytopathologic diagnosis of endometriosis by fine needle aspiration. STUDY DESIGN: We retrieved 10 cases of endometriosis from our files that had been diagnosed primarily by fine needle cytology (FNC) with subsequent tissue study. In some cases additional cytospin preparations and/or smears had been used for cytochemistry (periodic acid-Schiff stain, mucicarmine) or immunocytochemistry (pan-cytokeratin, cytokeratin 7, vimentin, CD10) using a 3-step streptavidin-biotin-immunoperoxidase reaction. RESULTS: The cell pattern and immunocytochemical profile of the cases suggested a diagnosis of endometriosis. All cases were histologically confirmed. CONCLUSION: With optimal preparations a confident cytologic diagnosis of endometriosis may be made with ease, permitting correct treatment of the disease and, in selected cases, planning of preoperative pharmacologic therapy.

Analysis of BRAF point mutation and RET/PTC rearrangement refines the fine-needle aspiration diagnosis of papillary thyroid carcinoma.

Point mutations in BRAF are genetic hallmarks of papillary thyroid carcinoma (PTC). In this retrospective study, we examined thyroid aspirates and corresponding paraffin-embedded surgical samples for the presence of BRAF mutations. Altogether, we examined 96 cases, including 69 PTCs, 19 follicular adenomas, and eight nontoxic nodular goiters for BRAF; 60 of these samples were also examined for RET/PTC rearrangements. The results were correlated with the cytological diagnosis and the final histopathology. The BRAF mutation (V599E) was detected in 38% of the samples that were PTC on histopathology; RET/PTC was found in 18% of the PTC cases. In all the cases, the presence of the genetic alteration was confirmed in the surgically resected tumor. The identification of BRAF mutation and RET/PTC refined the diagnosis of PTC in five of 15 samples that were considered either indeterminate or insufficient at cytology. No mutation was found in aspirates of follicular adenomas and nontoxic nodular goiters. These results indicate that BRAF mutation and RET/PTC rearrangements are molecular markers of PTC that can be applied to FNA in adjunct to traditional cytology.

Expression of NK-associated antigens in extramedullary lymph nodal blast crisis of chronic myeloid leukemia on fine-needle cytology.

A case is reported of a 62-yr-old male suffering from chronic myelogenous leukemia (CML) who developed an extramedullary, para-orthic lymph-nodal blast crisis without blood or bone marrow involvement and expression of CD56/NK associated marker. The diagnosis was performed on ultrasound-guided fine-needle cytology by an immunocytochemical and flow cytometric analysis. Conventional smears showed a monomorphous population of disperse, undifferentiated cells without cytoplasm. Cells showed fragile nuclei, vesicular chromatin, and evident nucleoli. Immunocytochemistry performed on cytospin slides were negative for cytokeratin, LCA, CD20, CD45Ro, and myeloperoxidase (MPO). Flow cytometry analysis proved the myeloid origin of the tumor by expression of CD13, CD34, and CD38 and showed aberrant expression of CD56. Cytological diagnosis was confirmed by histological examination. CD56 expression is generally an expression of NK lymphoid proliferation and may be observed in acute myelogenous leukemia but has rarely been reported in CML and its related blast crisis. This unusual expression, its possible explanation, the related technical problems, and clinicopathological aspects are discussed.