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Background: The management of cutaneous melanoma has dramatically changed in recent years thanks to the development of tyrosine kinase and immune-checkpoint inhibitors (ICIs). Thus, multiple biomarker testing is becoming ever more important to identify patients potentially eligible for these treatments. One reliable approach for molecular evaluation of metastatic melanoma is fine-needle cytology (FNC). To examine the utility of this approach for PD-L1 assessment, we evaluated the cellular adequacy of residual cell block (CB) material from metastatic melanomas previously tested for BRAF and NRAS mutations. Methods: We retrieved from our internal archives a series of FNC samples of metastatic melanoma subjected to molecular testing on residual CB material or dedicated needle rinse, between January 2016 and July 2022. Briefly, RT-PCR was adopted to assess BRAF and NRAS status, and SP263 assay was employed to assess PD-L1 expression level. 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, containing at least 100 viable cells. Conclusions: We highlighted the feasibility of PD-L1 assessment on 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 sources of nucleic acids for molecular testing, preserving CB material for ICC evaluation.

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.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.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 lt; 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.Our results confirmed that in a metastatic setting, FNC can reliably lead to the identification of the origin of the primary tumour.

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.

AimsOur laboratory is a centralised centre receiving routine non-small cell lung cancer (NSCLC) samples for programmed death ligand-1 (PD-L1) immunohistochemical (IHC) evaluation. Since literature data are not concordant here we review our clinical records to assess the rate of PD-L1 positive and negative NSCLC cases in real-world practice.MethodsPD-L1 expression was evaluated by a validated 22C3 IHC laboratory developed test on 211 prospectively collected routine NSCLC samples, received from 10 outside institutions. PD-L1 expression was assessed by the tumour proportion score (TPS) and reported by using a three cut-point system: TPSResultsOverall, 193 out of 211 samples (91.5%) meet the criteria for adequacy (more than 100 viable neoplastic cells). In 62.7% (121/193) of samples TPS was 50%. There was no significant difference in PD-L1 expression rates between different histotypes and site of sampling. Instead, a statistically significant difference was associated to the type of samples: in fact, cytological samples were more frequently negative for PD-L1 expression (TPS50%) than surgical resections and biopsies.ConclusionsWe present a referral laboratory experience on IHC PD-L1 expression of prospectively collected routine NSCLC samples. Data from the real-world practice can better clarify the percentage of PD-L1 positive and negative cases, to establish benchmarks for good practice standards.