A comparative study of INSM1 (clone MRQ70) immunoreactivity on CytoLyt® pretreated cytology and resection specimens of pancreatic neuroendocrine tumors.

INTRODUCTION: Insulinoma-associated protein 1 (INSM1) is a newly characterized sensitive and specific immunohistochemical marker for neuroendocrine (NE) tumors. Whereas more traditional NE markers, such as chromogranin A and synaptophysin, are cytoplasmic, INSM1 is uniquely nuclear and thus could serve as a useful addition to NE tumor workup. While application of immunohistochemical studies to cytology specimens is becoming increasingly relevant, knowledge of the effects of the certain fixatives as well as the pattern and intensity of immunoexpression are important considerations. METHODS: Sixteen cases of pancreatic neuroendocrine tumor (PanNET) diagnosed between 2015 and 2021 underwent both fine-needle aspiration, which was subsequently prepared in CytoLyt®-fixed cytology cell block (CCB), and surgical resection, in which specimens were prepared into formalin-fixed paraffin embedded blocks (FFPE). For all samples, INSM1 immunoreactivity was classified according to staining intensity and extent, then compared between CCBs and matched FFPEs. RESULTS: All 16 FFPE specimens demonstrated strong and diffuse INSM1 immunoreactivity, while only 10/16 (62.5%) CCBs were positive. Of those 10, only 2/10 (20%) demonstrated strong and diffuse reactivity. CONCLUSION: The choice of fixative has a demonstrable effect on the immunoreactivity of INSM1 in PanNET. Even though the sensitivity is lower in CytoLyt®-fixed cell block specimens, the addition of INSM1 is useful, especially in challenging cases that may be negative for one or more of the traditional NE markers.

Cytopathological analysis of salivary gland cancer: REFCOR recommendations by the formal consensus method.

OBJECTIVE: To determine the indications for fine-needle cytology and the modalities of frozen section pathological analysis in the management of salivary gland cancer. MATERIAL AND METHODS: The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group who drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group according to the formal consensus method. RESULTS: Fine-needle cytology is recommended as part of the diagnostic work-up for a major salivary gland tumor suspicious for malignancy. Fine-needle cytology should be performed after MRI to avoid artifacts. Frozen section analysis is recommended to confirm the malignant nature of the tumor, to adapt the extent of resection and to indicate neck dissection. Whenever possible, the entire tumor and adjacent salivary or periglandular tissue should be sent for frozen section analysis. CONCLUSION: Fine-needle cytology and frozen section analysis play an essential role in the management of salivary gland cancers.

Multiple predictive biomarker testing in melanoma: Another challenge in identifying the optimal approach on cytological samples.

BACKGROUND: The management of cutaneous melanoma has changed dramatically in recent years thanks to the development of tyrosine kinase and immune-checkpoint inhibitors (ICIs). Thus, multiple biomarker testing is becoming ever more important for the identification of patients who are potentially eligible for these treatments. One reliable approach to the molecular evaluation of metastatic melanoma is fine needle cytology (FNC). To examine the utility of this approach for assessing PD-L1 expression levels, we evaluated the cellular adequacy of residual cell block (CB) material from metastatic melanomas that were previously tested for BRAF and NRAS mutations. METHODS: We retrieved from our internal archives a series of FNC samples of metastatic melanoma that had been subjected to molecular testing on residual CB material or a dedicated needle rinse between January 2016 and July 2022. Real-time polymerase chain reaction was used to assess BRAF and NRAS status, and an SP263 assay was employed to ascertain PD-L1 expression levels. RESULTS: Overall, n = 19 cases were selected. Of these, 11 (57.9%) cases revealed a BRAF exon 15 p.V600E mutation, one case (5.3%) revealed NRAS mutation, and seven cases (36.8%) showed no mutations. Regarding PD-L1 assessment, 16/19 (84.2%) cases were deemed adequate, meaning they contained at least 100 viable cells. CONCLUSIONS: We highlighted the feasibility of assessing PD-L1 expression levels in residual CB material from metastatic melanomas previously tested for BRAF and NRAS mutations. Moreover, we pointed out that FNC needle rinses may be an alternative source of nucleic acids for molecular testing, preserving CB material for immunocytochemistry evaluation.

A roadmap for a comprehensive diagnostic approach to fine needle cytology of lymph node metastases.

OBJECTIVE: Fine needle cytology (FNC) is widely used as a first-line procedure in the diagnostic algorithm of lymphadenopathies. In a metastatic setting, a first-line diagnostic approach identifies non-haematopoietic malignancy; however, cytopathologists could also provide a second diagnostic level, identifying the origin of the primary tumour. This paper outlines a comprehensive and practical approach to the cytological diagnosis of lymph node metastases. METHODS: Cytological diagnoses of lymph node metastases performed over a 10-year period were selected and divided into two groups. The first group, labelled "oncological," comprised patients with a previous history of malignancy; the second group, labelled "naïve," included patients with no relevant history. Pathology records were retrieved to record microscopic findings, namely, background appearance, group architecture, and specific cell features; data from cell block (CB) preparations were also collected. RESULTS: Overall, 982 cases were selected: 497 cases (50.61%) in the naïve group, and 485 (49.39%) in the oncological group. Overall, a second diagnostic level was achieved in 834/982 cases (84.92%); cases diagnosed as carcinoma not otherwise specified were more frequent in the naïve group than in the oncological group (17.51% vs. 8.04%, P < 0.01). Notably, although CB material was available in only 44.87% of the naïve cases, we were able to achieve a second diagnostic level thanks to the integration of clinical and cytomorphological findings, plus lymph node topography, in 82.49% of the cases. CONCLUSION: Our results confirmed that in a metastatic setting, FNC can reliably lead to the identification of the origin of the primary tumour.

Pleomorphic liposarcoma with liver metastasis diagnosed by combined fine-needle aspiration cytology and core-needle biopsy.

Pleomorphic liposarcoma (PLPS) is the rarest liposarcoma subtype, with high-local recurrence and metastasis rates. Fine-needle aspiration cytology (FNAC) is successfully used in the diagnosis of primary or metastatic soft tissue tumors, but liver metastases of PLPS diagnosed by FNAC have never been reported. The cytological diagnosis depends on the identification of lipoblasts with sharply defined cytoplasmic vacuoles indenting and distorting the nucleus in the context of a pleomorphic tumor and in a proper clinical and imaging context. Despite its aggressive behavior, hematogenous liver metastases are rare, with just one case reported in literature. A case of PLPS liver metastasis and concomitant primary tumor diagnosed by FNAC and core needle biopsy is herein described.

Prevalence and predictors of thyroid cancer among thyroid nodules: a retrospective cohort study of 1,000 patients.

INTRODUCTION: Thyroid cancer is increasing in incidence globally due either to early detection (overestimation) or true increment. A recent debate concerns multinodular goitre (MNG) or toxic goitres which have classically been considered at a lower risk for cancer. METHODS: In this study, we enrolled retrospectively all patients with nodular goitre treated at our tertiary hospital and analysed their data with the aim of detecting the rate of cancer among different types of nodular goitre. We also studied predictors of incidental malignancy among thyroidectomies. RESULTS: A predilection for solitary thyroid nodules (STNs) was found in women of younger age, with STNs tending to be larger in comparison with MNG in the same age group. However, both types of nodules were at equal risk of harbouring malignancy. Thyroid Imaging Reporting and Data System (TI-RADS) and Bethesda scores were the only dependent predictors of malignancy within thyroid nodules. CONCLUSION: The authors recommend management of both STNs and MNG using the same algorithm.

A Novel Approach to Classification and Reporting of Lymph Node Fine-Needle Cytology: Application of the Proposed Sydney System.

Fine-needle cytology (FNC) is a useful diagnostic tool in the first line evaluation of lymphadenopathy of unknown aetiology. Nevertheless, considering the large number of conditions presenting as lymphadenopathy, lymph node cytology represents a challenging scenario. Recently, an expert panel published the proposal of the Sydney system for performing classification and reporting of lymph node cytopathology; the aim of the present study was to evaluate the applicability of this system. Thus, 300 lymph node FNCs performed over 1 year were reviewed and categorized according to the Sydney system classification. Overall, n = 20 cases (6.7%) were categorized as L1-inadequate/non-diagnostic; n = 104 (34.7%) as benign (L2); n = 25 (8.3%) as atypical (L3); n = 13 (4.3%) as suspicious (L4), and n = 138 (46%) as malignant (L5). FNC diagnoses were correlated with histopathologic and clinical follow-up to assess the diagnostic accuracy and the risk of malignancy (ROM) for each diagnostic category. Statistical analysis showed the following results: sensitivity 98.47%, specificity 95.33%, positive predictive value 96.27%, negative predictive value 98.08%, and accuracy 97.06%. The ROM was 50% for the category L1, 1.92% for L2, 58.3% for L3, and 100% for L4 and L5. In conclusion, FNC coupled with ancillary techniques ensures satisfactory diagnostic accuracy and the implementation of the Sydney system may improve the practice of cytopathologists.

Impact of ultrasonographic features, cytomorphology and mutational testing on malignant and indeterminate thyroid nodules on diagnostic accuracy of fine needle cytology samples: A prospective analysis of 141 patients.

OBJECTIVE: Fine needle cytology (FNC) is the first-line diagnostic method to determine the benign or malignant nature of thyroid nodules. The gray zone of cytological classifications remains, however, a crucial and challenging area for cytopathologists. DESIGN, PATIENTS AND MEASUREMENTS: In the present study, 141 thyroid cytological samples, with ultrasonographic suspicious features, have been prospectively analysed. Molecular analyses were performed by an innovative technology using two multiplex PCRs for the amplification of BRAF, N-H-K-RAS and RET exon genes. RNA samples were studied for RET/PTC1 and RET/PTC3 rearrangements by PCR amplification, and the conditions were set-up to study, with a single experiment, both wild-type PAX8 and PAX8/PPARÉ£ rearrangements. In total, 111 samples were examined for BRAF, N-H-KRAS and RET genes. An ultrasonographic, cytological and molecular correlation was also carried out in an attempt to suggest a possible way to manage the patients with thyroid nodules. Cyto-histological correlation was available in 115 cases, and it was used to verify the global diagnostic accuracy of this combined approach. RESULTS: According to the histopathological diagnosis, FNC accuracy was 100% for TIR5 and metastases; 89% for TIR4; 84% for TIR3A and 58% for TIR3B. About 11% of the studied samples showed either RET-PTC1 or RET/PTC3 chromosomal rearrangements, and only one sample simultaneously presented RET/PTC1 and RET/PTC3 rearrangements. PAX8/PPARÉ£ rearrangement was found in 6% of the samples. CONCLUSIONS: A multidisciplinary approach to the thyroid is therefore necessary to develop innovative methods suitable for an improved diagnostic and prognostic definition of thyroid cancer.

Fine-needle cytology of intraglandular parotid lymph node: A useful procedure in the management of salivary gland nodules.

BACKGROUND: Enlarged intra-parotid lymph nodes (pLNs) may be misdiagnosed at ultrasound (US) being rare entities and because of their similarities to parotid nodules. Fine-needle cytology (FNC) is used in the preoperative diagnosis of parotid nodules, and may be used on pLNs to assess their nature and the underlying pathological processes. METHODS: Twenty consecutive pLNs underwent US-guided FNC and rapid on-site evaluation (ROSE). Flow cytometry (FC) was also performed in all the cases. Immunoglobulin heavy chain (IGH) gene rearrangement PCR was performed in five cases. Data obtained were checked by follow-up and histological controls, when available. RESULTS: Ultrasound-guided FNC and ROSE identified 20 pLNs. According to FNC-FC and PCR data, pLNs were diagnosed as reactive processes(18), FL (1) and B-cell, NHL NOS (1). Clinical follow-up (18 cases) and histological assessment (three cases) confirmed FNC-FC diagnoses of reactive processes and two NHL. CONCLUSIONS: Fine-needle cytology is a sensitive procedure in the identification of pLNs. FNC is useful in the management of pLNs; it allows a simple follow-up in case of reactive processes and surgical excision in case of NHL, thus sparing useless excisions for reactive processes.

Lymph node fine-needle cytology in the era of personalised medicine. Is there a role?

The 2016 World Health Organisation revised classification of lymphoma has sub-classified well-defined entities and added a number of provisional entities on the basis of new knowledge on genetic, epigenetics and phenotypical data; prognostic and predictive features are also part of this classification. New knowledge on well-defined entities further enlightens the mechanisms of lymphomagenesis, which are more complex and multifactorial than once believed. Therapies are also more complex because traditional clinical trials have been integrated with new drugs and compounds with unique mechanisms of actions against distinct molecular targets. As lymphoma acquires additional genetic and phenotypic features over the time, pathological assessment is also necessary. Histological evaluation and tissue collection by surgical biopsies are necessary for phenotypical and molecular purposes; however, these are demanding procedures for both the patient and the health care system. At the same time, the choice of the best treatment for a specific entity, in different phases and different patients requires information that may not be available when the biopsy is performed. Fine needle aspiration cytology (FNAC) is successfully used in lymph nodes (LNs) in combination with different ancillary techniques and might be used to assess the phenotypic and genetic profile of specific targets and to get key information for therapy, in different phases and stages of the disease, with the option to re-check the same target over time, without surgical excision. This brief review describes LN-FNAC diagnostic criteria, current therapies for lymphomas and the potential role of LN-FNAC in selecting non-Hodgkin lymphomas patients for specific targeted treatments.

Retroperitoneal Tumor: A Silent Trespasser - Role of Image-Guided Fine-Needle Aspiration Cytology with Histopathological Correlation in Early Diagnosis.

OBJECTIVE: Retroperitoneal lesions present a great diagnostic challenge. Here we analyze the spectrum of retroperitoneal lesions and the utility of cytohistopathological correlation in early diagnosis. STUDY DESIGN: This 7-year study was undertaken in 338 patients with a retroperitoneal mass (kidney/adrenal/ pancreas/retroperitoneal lymph node, or soft tissue origin). In a prospective analysis, 81 patients underwent image-guided fine-needle aspiration cytology (FNAC) and 70 of the 81 underwent Tru-cut biopsy/histopathological evaluation. Clinical, radiological, and pathological details of 257 patients were retrieved from institutional records for retrospective analysis. A total of 119 patients, i.e., 70 in the prospective analysis and 49 in the retrospective analysis, had cytohistopathological correlation. RESULTS: Of the 338 cases, 88.4% were malignant (n = 274), 2.6% were benign (n = 8), 9% were nonneoplastic (n = 28), and 9% were inadequate (n = 28). Most were renal in origin (n = 106; 34.2%), followed by retroperitoneal soft tissue (n = 96; 31%). The most common nonneoplastic lesion was tubercular lymphadenitis (42.85%) and the most common benign lesion was paraganglioma (42.85%). The most common malignancy was renal cell carcinoma (21.16%), followed by Wilms' tumor (13.86%). In infancy and early childhood, Wilms' tumor, neuroblastoma, and germ cell tumor were the most common malignancies, while in middle age it was renal cell carcinoma, followed by pancreatic adenocarcinoma, and in the elderly age group it was metastatic carcinoma. Most malignancies were noted in the 5th to 6th decades. The overall sensitivity, specificity, and diagnostic accuracy of image-guided FNAC was 98.02, 72.22, and 94.12%, respectively. CONCLUSION: Image-guided FNAC is highly sensitive and specific for early diagnosis of an otherwise silent retroperitoneal mass. It saves patient from meticulous surgical procedures for diagnostic reasons and allows more rational planning of management. Knowledge of the distribution of tumors by age group helps to narrow down differential diagnoses.

Management of cytologic material, preanalytic procedures and biobanking in lymph node cytopathology.

The range of pathologies that lymph node (LN) fine needle cytology (FNC) may encounter is extremely wide and ancillary techniques, in addition to traditional smears, are generally required to reach reliable cytologic diagnoses. Storing part of the cytologic material may be useful or necessary for molecular testing. The main difficulties concern the generally small size of the sample and the different methods of acquisition of LN-FNC. Therefore, the preanalytic phase is extremely important for LN-FNC. This article outlines the management of LN-FNC material, vials, technical devices (e.g.: additional smears, cytospin slides, LBC slides, cards, resins, etc.) and main ancillary techniques to assess their optimal application, taking into account the different diagnostic needs and cell storage.

Scar site metastasis of renal cell carcinoma diagnosed on-site cytology: a case report.

BACKGROUND: Renal cell carcinomas (RCCs) have a propensity for widespread metastases and a wide range of survival rates. They can spread into adjacent organs by direct extension and can invade local or distant sites by lymphatic, hematogenous or lympho-hematogeneous pathways. Scar site metastasis is very rare. CASE PRESENTATION: We report a rare case of scar site RCC metastasis in a patient who underwent left radical nephrectomy 10 months ago. CONCLUSION: FNAC is a simple and easy technique that can help in the definitive diagnosis of subcutaneous lesions. A correct early stage diagnosis of metastatic RCC can considerably improve the survival rates.

Ultrasound-guided fine-needle capillary cytology of parotid gland masses coupled with a rapid-on-site evaluation improves results.

OBJECTIVE OF THE STUDY: To test whether a direct-on-site microscopic examination of fresh, unstained puncture slides by the radiologist decreases the rate of false-negative cases on ultrasound-guided fine-needle cytology of parotid gland masses. PATIENTS: Thirty parotid gland masses from 28 patients were punctured under ultrasound guidance. The same group was used as its control group. METHODS: After one or two passes, the material was spread on slides and air-dried (control group, without microscopic examination). For the study group, it was thus analyzed unstained under the microscope. A sample was considered adequate if at least six clusters of parotid cells were found per slide on at least two slides. For the study group, new punctures were obtained and slides prepared until this condition was fulfilled. RESULTS: Of the 30 evaluated masses, 100% benefited from a cytological diagnosis after microscopy. Twenty-four were adequate in the control group, while 30 were adequate in the study group. The maximum number of punctures to obtain an adequate sample was six. On-site direct microscopy significantly increased the number of adequate specimens by 20% (P=0.03, CI [1.63-20%]). CONCLUSION: Direct and systematic examination of slides by a radiologist avoided the risk of false-negative results caused by having insufficient sample material.

Comparative analysis of diagnostic adequacy rate between aspiration and nonaspiration techniques of fine-needle cytology in patients with thyroid cancer and ultrasonographically suspicious cervical lymph nodes.

BACKGROUND: We aimed to compare nonaspiration (NAS) and aspiration (AS) techniques in the evaluation of fine-needle cytology of lymph node (FNC-LN) in terms of diagnostic adequacy of cytologic material. METHODS: One hundred and twenty-three superficial cervical LNs in 75 patients who underwent NAS and AS-FNC-LN in the same visit were evaluated. Cytological results were categorized as diagnostic and nondiagnostic. RESULTS: The rates of malignancy were 13.8% in AS versus 16.3% in NAS technique, whereas nondiagnostic cytology was detected in 43.1% and 25.2%, respectively (P = .549 and P < .01). CONCLUSIONS: The diagnostic adequacy rate in NAS-FNC-LN was significantly higher than AS-FNC-LN. However, NAS technique seems to be more simple and comfortable. We suggest both NAS and AS-FNC-LN in cytologic evaluation of suspicious cervical LNs until the diagnostic accuracy is determined with prospective studies.

Accuracy of Fine Needle Cytology in Histological Prediction of Papillary Thyroid Carcinoma Variants: a Prospective Study.

Fine needle cytology (FNC) is a crucial procedure in the preoperative diagnosis of thyroid tumors. Papillary thyroid carcinoma (PTC), in its classic variant (cPTC), is the most common malignant neoplasm of the thyroid. Several histological variants of PTC have been described, each one with its own characteristics and prognosis. The ability of FNC to identify the variants represents a challenge even for a skilled pathologist. The aim of this study was to evaluate the diagnostic cytological accuracy of FNC in PTC and to look for specific features that could predict the different variants. This was a single center prospective study on 128 patients who received a diagnosis of PTC on FNC. The smears were blindly reviewed by two cytopathologists to create a frequency score (0, 1, 2, 3) of the features for each variant. The cytological parameters were divided into three groups: architectural, nucleo-cytoplasmic, and background features. Univariate analysis was performed by chi-square test with Yates correction and Fisher exact test as appropriate. Multiple regression analysis was performed among the variables correlated at the linear correlation. The correlation study between cytology and histology showed an accuracy of FNC in classic, follicular, and oncocytic PTC variants of 63.5, 87.5, and 87% respectively. Familiarity with cytological features may allow an early diagnosis of a given PTC variant on FNC samples. This is fundamental in a preoperative evaluation for the best surgical approach and subsequent treatment.

Risk of malignancy in thyroid nodules classified as TIR-3A: What therapy?

BACKGROUND: The aim of the present study was to assess the clinical applicability of the TIR3A category in managing thyroid nodules, to examine the malignancy rates of TIR 3A and TIR 3B nodules, and to suggest management guidelines for these nodules. MATERIALS AND METHODS: Thyroid cytologies performed in patients referred to our Department between January 2014 and August 2016 were classified according to the guidelines published by the SIAPEC. 102 cases were included in this retrospective study and were divided into two groups: 19 TIR3A were included in group A and 83 TIR3B in group B. RESULTS: In group A, malignancy was diagnosed in 4 (21.1%) cases, papillary thyroid cancer was found in 3 patients and follicular thyroid cancer in 1; one case was classified as microcarcinoma, in two cancer was multicentric and bilateral and in one central node metastases were observed. In Group B malignancy was diagnosed in 48 (57.8%) patients, papillary thyroid cancer was found in 36 patients and follicular cancer in 12; microcarcinoma was observed in 25 cases, 12 were unilateral multicentric and 7 bilateral multicentric; in 3 cases central node metastases were present. CONCLUSION: Thyroid nodules with TIR3A cytology have a lower risk of malignancy than TIR3B cases, for which the new SIAPEC classification has proved accurate and effective. Malignancy rates in nodules with TIR3A cytology are higher than expected, although the real and accurate definition of the risk is extremely difficult. The recommendation to perform an accurate follow-up and repeat the fine-needle aspiration still appears the best option. For better management of patients with TIR3A cytology a careful assessment of risk factors and ultrasound characteristics is always needed. Further multicenter studies with longer follow-up are needed to better define the efficacy of this classification, the actual cancer risk, and the best management of these lesions.

Multiplex PCR approach to simultaneously identify several mutations in fine needle cytology thyroid samples.

The most frequent initial manifestation of thyroid cancer is the appearance of a nodule. More than 20% of the general population has a palpable thyroid nodule and the percentage rises to 70% based on ultrasound identification. In 95% of cases the nodule is simply a hyperplastic or benign lesion. The most reliable diagnostic test for thyroid nodules is fine needle aspiration (FNA), but cytological discrimination between malignant and benign follicular neoplasms remains difficult. Cytological analysis is now, almost routinely, being combined with molecular genetics to enable the pathologist to make a more objective diagnosis. In this study, we performed the molecular analysis using a new simplified procedure that involves a panel of BRAF, RAS, RET and RET/PTC gene mutations in easily obtainable FNA samples, in the attempt to improve the efficacy of the FNA diagnosis of thyroid nodules and thus patient management. In this new procedure, PCR and sequencing analysis are used to detect point mutations, and, in parallel, RT-PCR is used to detect the chimeric RET/PTC1 and RET/PTC3 transcripts in RNA extracted from FNA.

A retrospective study of ultrasound and FNA cytology investigation of thyroid nodules: working towards combined risk stratification.

The British Thyroid Association recommended in new guidelines on thyroid cancer treatment [Kwak et al. (Korean J Radiol 14:110-117, 2013)] that ultrasound grading of thyroid nodules should be incorporated into MDT management. A retrospective study was carried out to determine that the impact of US grading has had on MDT decision making in practice. The design used in the study is a retrospective review of case notes. The study was carried out in the hub hospital for thyroid cancer in the North west London Cancer network. We included consecutive patients referred to the regional thyroid multidisciplinary meeting between August 2014 and May 2015 for investigation of thyroid nodules. Data were collected on patient demographics, co-morbidity, thy grading, ultrasound grading, surgery, post-operative histology, and radioactive iodine treatment details. Accuracy of cytology and ultrasound in diagnosing malignancy was correlated to definitive histology. 99 patients with thyroid nodules were included in the study. 97% of patients had at least one fine needle aspiration and 75% had ultrasound grading. Thy3f (Bethesda IV) nodules were more likely to be carcinoma if associated with a U4 grade rather than U3 (67 vs 18%, p = 0.028). Ultrasound grading has recently been introduced to the standard practice in investigation of thyroid nodules. Further assessment of the accuracy of ultrasound grading in clinical practice may allow us to risk-stratify thy3a/thy3f (Bethesda III/IV) lesions and personalise treatment.

Fine needle cytology pre-surgical differentiation of parathyroid neoplasms: Is it reliable?

BACKGROUND: Fine needle cytology (FNC) of a parathyroid neoplasia (PN) is reliable, but needs to be confirmed by Parathormone (PTH) and Thyroglobulin (TG) immunoassay on needle washing or by immunocytochemistry (ICC) evaluation. The differentiation between parathyroid adenoma (PA), atypical adenoma (PAA) and carcinoma (PC) is difficult on histology or even impossible on FNC. The aim of this study was to evaluate possible cytological criteria to classify FNC-PN further. METHODS: Twenty-three FNC samples of PN and parathyroid cysts were rather then have been reviewed. The series includes 18 PNs, 4 cysts and 1 Thyr3B (histologically diagnosed as PA). Cytological features were: cellularity, patterns (follicular, solid or papillary), clear, oncocytic, isolated cells, nuclear atypia, cytoplasmic inclusions, nucleoli and mitoses. Data were compared with the histological controls. RESULTS: Seventeen PNs, 2 cysts and 1 Thyr3B FNC samples were histologically diagnosed as PA (16), PAA (2) and PC (2). Two cysts and 1 PN were not confirmed histologically. Cytological features and incidences were: high cellularity (1 PA, 1 PAA, 2 PCs), follicular (8 PAs, 1 PAA), solid (5 PAs, 1 PC), papillary pattern (1PA, 1 PAA, 1 PC), clear cells (4 PAs, 1 PAA, 2 PCs), oncocytic cells (6 PAs, 1 PAA, 2 PCs), isolated cells (5 PAs, 2 PAAs, 2 PCs), nuclear atypia (2 PAs, 1 PAA, 2 PCs), cytoplasmic inclusions (4 PAs, 2 PCs), nucleoli (2 PCs) and mitoses (2 PCs). CONCLUSION: Evident nucleoli and mitoses may suggest the differentiation between PA and PC. However, further investigations are required to confirm these preliminary observations.