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.

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.

Cytology-based gene mutation tests to predict response to anti-epidermal growth factor receptor therapy: a review.

Recent therapeutic progresses in nonsmall cell lung cancer (NSCLC) and in colorectal cancer (CRC) are based on agents that specifically target the epidermal growth factor receptor (EGFR). To identify the patients most likely to benefit from such therapies, EGFR or KRAS gene mutation tests are mandatory, respectively, in NSCLC and in CRC. In patients with locally advanced or metastatic disease, exploiting cytological samples for these tests avoids not curative surgery. Here, we review the studies that have applied gene mutation assays on cytological samples of NSCLC and CRC to select patients for anti-EGFR therapy. We argue that the standard of quality of gene mutation tests on cytological samples is closely dependent on the extent of the cytopathologist's involvement.

Impact of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in lymph nodal and mediastinal lesions: a multicenter experience.

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is an established procedure in lung cancer (LC) staging and in the diagnosis of mediastinal masses. Most of the experiences reported refer to single specialized centers where dedicated teams of endoscopists and pathologists perform the procedure. We report the EUS-FNA experience of a cooperation group involving clinicians and cytopathologists from three hospitals. Fifty-seven consecutive EUS-FNA of mediastinal nodes in LC patients, eight mediastinal and two subdiaphragmatic masses were collected in 3 years. EUS-FNA was performed by two endoscopists and three experienced pathologists. On-site evaluation was performed in all cases by the three cytopathologists. Lymph node negative cases underwent surgery, which confirmed the cytological diagnoses but also detected two false negatives. Four of the 10 EUS cytological diagnoses of mediastinal and subdiaphragmatic masses were histologically confirmed. All EUS diagnoses were blindly reviewed by three pathologists to assess intra and interpersonal reproducibility. FNA-EUS diagnoses were: 10 inadequate (17%), 10 negative (17%), 4 suspicious (7%) and 33 positive (59%). Diagnoses of mediastinal and subdiaphragmatic masses were: relapse of lung carcinoma (3), mesenchimal tumor not otherwise specifiable (3), gastrointestinal stromal tumor (GIST) (1), esophageal carcinoma (2) and paraganglioma (1). The sensitivity attained was 85% and the specificity 100%; revision of the slides demonstrated a significant diagnostic reproducibility of the three cytopathologists (P < 0.5). The sensitivity and specificity attained were similar to those reported in the literature suggesting that experienced cytopathologists and endoscopists from different institutions can employ the same procedure reaching comparable results.

KRAS testing on colo-rectal carcinoma cytological imprints.

Anti-EGFR monoclonal antibodies, cetuximab, and panitumumab, are administrated under the condition that advanced colo-rectal cancer (CRC) carries a wild-type KRAS gene. Thus, clinicians request pathologists to genotype KRAS before treatment. In the near future routine mutation testing at the same time of the surgery may be implemented. The reliability of a rapid KRAS testing on ex vivo cytological samples obtained by direct scraping of the colon tumour tissue is here evaluated. A consecutive series of 20 surgically resected, primary CRC specimens was analysed. Fresh tissue from CRC was scraped with a scalpel blade, smeared on uncoated glass slides, air-dried and Diff-Quik stained to ensure malignant cell presence. The same tissue area was also histologically processed. Exon 2 KRAS gene mutations were evaluated on both cytological and histological specimens by dideoxy sequencing and by the DxS KRAS Mutation Test Kit (DxS, Manchester, England). Data obtained on on imprint cytology and matched histological samples showed full concordance; however, the mutation frequency was slightly higher (35%) by the DxS KRAS Mutation Test Kit than by the dideoxy sequencing (30%). Thus, colon cancer imprint cytology sample is a reliable biospecimen for both dideoxy-sequencing and DxS KRAS Mutation Test Kit analysis and it may be useful to abbreviate the KRAS assay turnaround time.

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.

UbcH10 expression on thyroid fine-needle aspirates.

BACKGROUND: Thyroid fine-needle aspiration (FNA) samples belonging to the follicular neoplasm/suspicious for malignancy classes are controversial. The authors identified UbcH10 as a marker useful in the diagnosis of several neoplasms, including thyroid cancer. Here, analysis of UbcH10 expression by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry was applied to FNAs. METHODS: A series of 84 follicular neoplasm/suspicious for malignancy FNAs with histological follow-up (30 malignant) was prospectively collected. UbcH10 immunostaining was performed on cell blocks and compared with that of the proliferation marker Ki-67. At the mRNA level, UbcH10 was compared with CCND2 and PCSK2 expression, these latter being the best performing components of the previously reported 3-gene assay; to determine the diagnostic accuracy, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for each gene individually and in combination was evaluated. RESULTS: UbcH10 and Ki-67 shared a similar pattern; although UbcH10 expression was higher in malignant than in benign lesions (P < .001), staining was sporadic, and the cutoff value derived by the ROC analysis was too low (1.25%) for routine application. Conversely, UbcH10 expression assessment by quantitative RT-PCR was effective. UbcH10 mRNA levels associated with malignant histology were significantly higher than those associated with benign histology (P = .02). The AUC was 0.74 for UbcH10, 0.81 for CCDN2, 0.62 for PCSK2, and 0.84 for UbcH10 and CCND2 combination. CONCLUSIONS: UbcH10 quantitative RT-PCR analysis, rather than immunohistochemistry, is useful to increase the detection of malignancy in thyroid FNAs. UbcH10 may be added as a panel component in quantitative RT-PCR-based assays.

Metastasis of colon cancer to the thyroid gland: a case diagnosed on fine-needle aspirate by a combined cytological, immunocytochemical, and molecular approach.

Fine-needle aspiration (FNA) with cytological evaluation reliably diagnoses primary and secondary thyroid neoplasms. However, identifying the primary origin of a metastatic process involving the thyroid gland is challenging. In particular, metastasis of colon cancer to the thyroid gland is very rare. In this case report, a right lobe solid thyroid nodule in a 66-year-old male was aspirated. FNA cytology showed necrosis and atypical tall columnar cells; since, the patient at age 60 had undergone surgery for a sigmoid-rectal cancer metastasizing to the liver and subsequently to the lung, a suspicion of metastasis from colon cancer was raised. This was corroborated by cell-block immunocytochemistry showing a cytokeratin (CK) 7 negative/CK20-positive staining pattern; thyreoglobulin and TTF-1 were both negative. Since KRAS codon 12/13 mutations frequently occur in colon cancer, whereas they are extremely uncommon in primary thyroid tumors, DNA was extracted from the aspirated cells, and KRAS mutational analysis was carried out. The codon 12 G12D mutation was found; the same mutation was evident in the primary cancer of the colon and in its liver and lung metastasis. Thus, a combined cytological, immunocytochemical and molecular approach unquestionably correlated metastatic adenocarcinoma cells aspirated from the thyroid to a colo-rectal origin.

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.

KRAS mutation analysis on cytological specimens of metastatic colo-rectal cancer.

Recent evidences showed that metastatic colorectal cancer (CRC) patients with tumors harboring a KRAS gene mutation do not derive benefit from the administration of epidermal growth factor receptor-directed monoclonal antibodies. Typically, the specimens available for KRAS mutational analysis are formalin-fixed paraffin-embedded (FFPE) primary tumor tissue blocks. However, in patients with rectal tumours undergoing neoadjuvant therapy, the source of FFPE material is limited. In this setting, CRC cytological samples taken from the metastatic site may be exploited. However, these specimens show at least some degree of necrosis; thus, their suitability for the KRAS assay needs to be tested. Here, we show that 18/19 (94.7%) metastatic CRC smears were perfectly adequate for codon 12 and 13 KRAS mutational analysis by direct gene sequencing. Only one case (5.3%) showing abundant necrotic debris and poor cellular preservation was not informative for KRAS status. Codon 12 gene mutations were found in 4/18 (22.2%) of the adequate cases (c35G>T n = 2; c34G>T n = 1; c35G>A n = 1). Concordance between cytological and FFPE samples, both available in 13 patients, occurred in 92.3% (12/13) of the cases. Thus, whenever histological specimens of CRC are notavailable, KRAS testing may be reliably performed on cytological specimens.

Preparation of thyroid FNA material for routine cytology and BRAF testing: a validation study.

V600E BRAF mutation is emerging as an independent marker of papillary thyroid carcinoma aggressive behavior. Papillary thyroid carcinomas harboring this mutation should be extensively resected. However, this requires an unquestionable cytological diagnosis of malignancy. Thus, cytological specimens should be properly handled to provide both morphological and molecular information. Here, we assessed whether our method of preparation of fine-needle aspiration material is suitable for both tests. A series of 128, routinely performed, fine-needle aspirations was analyzed. Each nodule was punctured three times. A representative Diff-Quik smear prepared from the first two passages was evaluated onsite. When microscopy was diagnostic (n = 44), the third needle pass was dedicated to harvest material for BRAF testing; in the remaining cases (n = 84), additional direct smears for cytology were prepared and the remaining material in the needle plus the needle rinsing was collected for BRAF testing. Cellularity was adequate in 126/128 (98%) cases. Cytological diagnoses were inadequate (2%), benign (85%), follicular lesion of undetermined significance (5%), follicular neoplasms (2%), suspicious for malignancy (2%), and malignant (4%). Higher average of extracted DNA concentration was observed in the dedicated pass group (25.9 vs 7.95 ng/microl). However, the rate of successful exon 15 BRAF amplification was similar with (43/44; 97.7%) or without (79/84; 94%) the dedicated pass. Thus, our protocol is suitable for both tests. Whenever necessary BRAF testing may also be performed on the residual samples of thyroid nodules, without interfering with routine cytology.

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.

Cyclin D1 and D3 overexpression predicts malignant behavior in thyroid fine-needle aspirates suspicious for Hurthle cell neoplasms.

BACKGROUND: Thyroid fine-needle aspiration (FNA) samples that feature a follicular-patterned, monotonous Hurthle (oncocytic) cell population cannot be diagnosed reliably. The authors of this report recently identified cyclin D3 overexpression on histologic sections of Hurthle cell carcinoma. In this study, they assessed the diagnostic value of cyclin D3 immunohistochemistry added to routine cytology. METHODS: Fifty-one FNA samples that were suspicious for Hurtle cell neoplasia and that had histologic follow-up (19 malignant cases) were examined. Cyclin D3 expression levels were evaluated in cell block preparations and were compared with levels of the closely related cyclin D1 protein. RESULTS: Greater than 25% positive cells were used as the cutoff point, as suggested by previous studies. Cyclin D1 and cyclin D3 were highly specific (100% for both) and fairly accurate (75% and 92%, respectively) in distinguishing between benign and malignant oncocytic lesions; the positive predictive value (PPV) for each was 100%. However, both cyclins D1 and D3 had low sensitivity (32% and 79%, respectively) and low negative predictive value (NPV) (71% and 89%, respectively). In contrast, by adopting balanced receiver operating characteristic-derived positive cutoff values, cyclin D1 (>or=6.5%) and cyclin D3 (>or=7.5%) were found to be highly sensitive (100% for both) and accurate (90% and 94%, respectively); and the NPV was 100% for both. In contrast, cyclins D1 and D3 had low specificity (84% and 91%, respectively) and a low PPV (79% and 86%, respectively); however, these values improved in samples that were positive for both cyclins (sensitivity, 100%; specificity, 94%; PPV, 90%; NPV, 100%; and accuracy, 96%). CONCLUSIONS: Cyclin D3 increased the suspicion of malignancy in indeterminate oncocytic lesions; its diagnostic performance depended on the cutoff point used and was enhanced further when combined with cyclin D1.

Clonal B-cell population in a reactive lymph node in acquired immunodeficiency syndrome.

A 40-year-old female, HIV positive, stage C, since 4 years, complained of a right cervical lymph node swelling. Two years before, the patient had been diagnosed with follicular B-cell non-Hodgkin lymphoma (FL); she had been treated with four cycles of multiagent chemotherapy plus rituximab, the last cycle being administered 10 months before coming to our attention. An ultrasound (US) guided fine-needle cytology (FNC) showed an atypical lymphoid cell proliferation. The phenotype evidenced by flow cytometry (FC) analysis was D5: 10%, CD19: 49%, CD23: 10%, FMC7: 0%, CD10: 40%, CD10/19: 40%, lambda light chain 40%, kappa light chain 0%. FDG-positron emission tomography (PET/CT) scan showed positivity in the corresponding cervical area. Since low LDH values and a reduced lymph node size were observed, the lymph node was therefore excised; the histology revealed a reactive hyperplastic lymph node with florid follicular pattern. A subsequent PCR analysis, performed on DNA extracted from a whole histological section, did not evidence IgH rearrangement. The patient is currently undergoing strict clinical and instrumental follow-up, including PET every 3 months; after 13 months, she is alive without recurrence of lymphoma. Clonal B-cell populations in non-lymphomatous processes have been described in mucosa-associated lymphoid cell populations and reactive lymph nodes, and are considered non-malignant, antigen driven, proliferations of B-lymphocytes determined by an abnormal response to bacterial or viral antigen stimulation. The present case occurred in an HIV patient and was clinically complex because of the patient's history of FL. This experience suggests much attention in the evaluation of radiological, cytological, and FC data and in clinical correlation in patients suffering from autoimmune or immunodeficiency syndromes.

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.

Cytologic, flow cytometry, and molecular assessment of lymphoid infiltrate in fine-needle cytology samples of Hashimoto thyroiditis.

BACKGROUND: The thyroidal lymphoid infiltrate (TLI) in Hashimoto thyroiditis (HT) represents the substrate from which thyroid lymphoma may arise. The objective of the current study was to classify the TLI in HT by comparing the cytologic features with flow cytometry (FC) data and evaluating the kappa/lambda light chain ratio and its molecular assessment. METHODS: Fine-needle aspiration cytology (FNAC) was performed in 34 patients with HT with nodular or diffuse palpable enlargement of the gland. Two or 3 passes were performed to prepare traditional smears, FC, and immunophenotyping, and RNAlater suspensions for molecular assessment. FC was performed using the following antibodies: CD3, CD5, CD4, CD8, CD10, CD19, and kappa and lambda light chains. In 4 cases, high molecular weight DNA was extracted and used for polymerase chain reaction (PCR) to amplify the variable diversity joining region of the heavy chain immunoglobulin (Ig) genes (IgH). Statistical analysis was performed to evaluate possible associations between clinical ultrasound presentation, cytologic pattern, and TLI phenotype. Light chain expression was evaluated as the percentage of the expressing cells (20%) and as the kappa/lambda ratio. RESULTS: Smears were classified as "lymphocytic," "lymph node-like," or "mixed." FC demonstrated T cells (CD3 positive [+], CD5+) in all cases, and T cells and B cell (CD19+, CD10+/-) lymphocytes in 22 cases. Light chains were expressed in 30 cases (in <20% of the gated cells in 13 cases and in >20% of the gated cells in 17 cases). Five cases demonstrated small kappa/lambda ratio imbalances and PCR analysis demonstrated diffuse bands in the gel and Gaussian curves at the heteroduplex. Statistical analysis indicated significant associations between the "lymphocytic" pattern and T-cell phenotype and between the "lymph node-like" pattern and B-cell phenotype. A significant association also was observed between light chain restriction and low light chain expression (P < .005). CONCLUSIONS: The cytologic pattern of TLI in HT is quite representative of the clinical presentation and phenotypic cell type. Small light chain imbalances are not sustained by heavy chain Ig gene (IgH) rearrangements. FNA coupled with FC may contribute to making the distinction between florid TLI and non-Hodgkin lymphoma.