Pathological T3 Non-Small Cell Lung Cancer with satellite nodules: Number or size, what does matter?

BACKGROUND: Non-small Cell Lung Cancer (NSCLC) with intralobar satellite nodule are defined as T3 (T3SN). We investigated the main features of these tumors and analyzed their impact on Overall Survival (OS). METHODS: This was a retrospective multicentric study including all pT3SN NSCLC operated on between 2005 and 2020, excluding patients with multifocal ground-glass opacities; who received induction therapies; N3 or stage IV. The diameter of largest (LgN) and smallest nodule (SmN), the total diameter (sum of diameter of all nodules, TS), and the number of SN were measured. RESULTS: Among 102 patients, 64.7 % were male. 84.3 % of patients had one SN (84.3 %), 9.8 % two SN while 5.9 % more than 2 SN. 63 patients were pN0. LgN (p = 0.001), SN (p = 0.005) and TS (p = 0.014) were significantly related to lymph-node metastasis; the LgN and TS were related to visceral pleural invasion (p < 0.001). Five-year OS was 65.1 %; at univariable analysis more than 2 satellite nodules, LgN and TS were significantly related to worse OS; at multivariable analysis, TS (Hazard Ratio [HR] 1.116 95 % Confidence Interval [CI] 1.008-1.235, p = 0.034) was an independent prognostic factors for OS. No significant prognostic factors were found for DFS at multivariable analysis. In pN0 patients, LgN (HR 1.051, 95 % CI 1.066-1.099, p = 0.027) and non-adenocarcinoma (HR 5.315 CI 95 % 1.494-18.910, p = 0.010) influenced OS. CONCLUSIONS: Tumor size is related to tumor's local invasiveness. TS is an independent prognostic factor for OS. Patients with more than 2 SN seem to be at higher risk for death and recurrence.

Histopathology of growth hormone-secreting pituitary tumors: State of the art and new perspectives.

Somatotroph (GH) adenomas/PitNETs typically arise from adenohypophysis and are biochemically active, leading to acromegaly and gigantism. More rarely, they present with ectopic origin and do not present overt biochemical or clinical features (silent variants). Histopathological examination should consider the clinical and radiological background, and include multiple steps assessing tumor morphology, pituitary transcription factors (PTFs), hormone secretion, proliferation markers, granulation, and somatostatin receptors (STRs), aimed at depicting as better as possible tumor origin (in case of non-functioning and/or metastatic tumor), and clinical behavior, including response to treatment. GH-secreting tumors are part of the Pit-1 family tumors and can secrete GH only (pure somatotrophs) or co-secrete prolactin (mixed tumors; in this case, various histological subtypes have been identified). Each subtype presents unique radiological, biochemical, and clinical characteristic. Therefore, the integration of biochemical, clinical, radiological, and histopathological elements is fundamental for proper diagnosis and management of pituitary adenomas/PitNETs, to be performed in referral Centers. In more recent times, the importance of genetic and epigenetic evaluation in the characterization of pituitary tumors (i.e., early identification of aggressive variants) has been outlined by some large studies, with the intention of improving targeted treatments.

Analysis of GATA3 and FOXA2 expression suggests that downregulation of genes involved in the maintenance of a mature yolk sac tumor phenotype may underlie sarcomatoid transformation.

In the post-chemotherapy setting, germ cell tumors of the testis (GCTT) that resemble non-specific sarcomas and co-express cytokeratins and glypican-3 (GPC3) are diagnosed as "sarcomatoid yolk sac tumor postpubertal-type (YSTpt)". The diagnosis of sarcomatoid YSTpt is clinically relevant but challenging due to its rarity, non-specific histology, and negative α-fetoprotein (AFP) staining. Recently, FOXA2 has emerged as a key-gene in the reprogramming of GCTT (activating the transcription of several genes, among which GATA3), and immunohistochemical studies showed that GATA3 and FOXA2 have a higher sensitivity for non-sarcomatoid YSTpt than GPC3 and AFP. We found that sarcomatoid YSTpt did not express FOXA2 [0: 14/14 (100%)] and showed focal expression of GATA3 [0: 12/14 (85.7%), 1 + : 2/14 (14.3%)], thus suggesting that these markers are not useful in diagnosing this tumor. Furthermore, we proposed a potential mechanism of sarcomatoid transformation in the post-chemotherapy setting of GCTT, mediated by the downregulation of FOXA2 and GATA3.

Evaluation of an institutional series of low-grade oncocytic tumor (LOT) of the kidney and review of the mutational landscape of LOT.

The 2022 WHO classification of urinary and male genital tumors introduced several novel kidney entities exhibiting eosinophilic/oncocytic features with specific mutational backgrounds. Thus, molecular techniques, such as next-generation sequencing (NGS), became more commonly used for their evaluation. We studied 12 low-grade oncocytic tumors (LOT) of the kidney (from 11 patients), identified in a cohort of 210 eosinophilic/oncocytic renal tumors, diagnosed in our institution between October 2019 and May 2023, which represented 5.7% (12/210) of all eosinophilic/oncocytic renal tumors during this period. We reviewed their clinicopathologic, histologic, and immunohistochemical features, as well as their mutational profiles. We also reviewed the literature on NGS-derived data of LOT, by selecting papers in which LOT diagnosis was rendered according to the criteria proposed initially. Median age was 65 years (mean: 63.5; range 43-79) and median tumor size was 2.0 cm (mean: 2.2; range: 0.9-3.1). All tumors were positive for PAX8, CK7, and GATA3, and negative or focally positive for CD117/KIT. We found the following gene mutations: MTOR ((6/11), 54.5%)), TSC1 ((2/11), 18.2%)), and 1 had both NOTCH1 and NOTCH4 ((1/11), 9.1%)). Wild-type status was found in 2/11 (18.2%) patients and one tumor was not analyzable. A review of 8 previous studies that included 79 LOTs revealed frequent mutations in the genes that regulate the mammalian target of rapamycin (mTOR) pathway: MTOR (32/79 (40.5%)), TSC1 (21/79 (26.6%)), and TSC2 (9/79 (11.4%)). Other mutated genes included PIK3CA, NF2, and PTEN, not typically known to affect the mTOR pathway, but potentially acting as upstream and downstream effectors. Our study shows that LOT is increasingly diagnosed in routine practice when applying the appropriate diagnostic criteria. We also confirm that the mTOR pathway is strongly implicated in the pathogenesis of this tumor mainly through MTOR, TCS1, and TSC2 mutations, but other genes could also be involved in the pathway activation, especially in LOTs without "canonical" mutations.

FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.

AIMS: Yolk sac tumour postpubertal-type (YSTpt) shows a wide range of histological patterns and is challenging to diagnose. Recently, forkhead box transcription factor A2 (FoxA2) emerged as a driver of YSTpt formation and a promising marker for diagnosing YSTpt. However, FoxA2 has not been tested in the different patterns of YSTpt. This study aimed to assess the staining pattern of FoxA2 in te different patterns of YSTpt and other germ cell tumours of the testis (GCTT), comparing it with glypican-3 (GPC3) and α-fetoprotein (AFP). METHODS AND RESULTS: FOXA2, GPC3 and AFP immunohistochemistry was performed on 24 YSTpt (24 microcystic/reticular, 10 myxoid, two macrocystic, five glandular/alveolar, two endodermal sinus/perivascular, four solid, two polyembryoma/embryoid body and two polyvesicular vitelline) and 81 other GCTT. The percentage of positive cells (0, 1+, 2+, 3+) and the intensity (0, 1, 2, 3) were evaluated regardless of and within each YSTpt pattern. FoxA2 was positive in all YSTpt (24 of 24) and all but one (23 of 24) exhibited 2+/3+ stain, with higher intensity [median value (mv): 2.6] than AFP (1.8) and GPC3 (2.5). Both FoxA2 and GPC3 were positive in all microcystic/reticular (24 of 24), myxoid (10 of 10), macrocystic (two of two), endodermal sinus/perivascular (four of four) and polyembryoma/embryoid body (two of two) patterns. Nevertheless, only FoxA2 was positive in all glandular/alveolar (five of five), solid (four of four) and polyvesicular vitelline (two of two) patterns. The intensity of FoxA2 was higher than AFP and GPC3 in almost all YST patterns. In the other GCTT, FoxA2 was positive only in teratoma postpubertal-type (Tpt) [13 of 20 (65%)], with staining almost exclusively confined to the mature gastrointestinal/respiratory tract epithelium. CONCLUSIONS: FoxA2 is a highly sensitive and specific biomarker that supports the diagnosis of YSTpt. FoxA2 is superior to GPC3 and AFP, especially in rare and difficult-to-diagnose histological patterns of YSTpt, but mature glands of Tpt could represent a potential diagnostic pitfall.

"Paradoxical" p16 overexpression in cutaneous melanoma: Molecular and immunohistochemical analysis of a rare phenomenon with a focus on cell cycle regulatory molecules.

BACKGROUND: One of the most relevant genetic alterations in cutaneous melanoma (CM) is the biallelic inactivation/loss-of-heterozygosis (LOH) of cyclin-dependent kinase inhibitor 2 A (CDKN2A), which results in the immunohistochemical loss of p16 frequently found in CM. However, we recently described a rare case of dermal/deep-seated melanoma arising in giant congenital nevus (DDM-GCN) with p16 overexpression combined with p53 loss and tumor protein 53 (TP53) mutation. Herein, we reported a case series of CM with p16 overexpression and analyzed their clinicopathologic features, immunohistochemical expression of the cell cycle regulatory molecules (CCRM: p53, p21, Cyclin D1, Rb), and mutational landscape. METHODS: We retrospectively tested for p16 all cases of CM diagnosed at our institution between January 1st 2019-April 1st 2022. In CM with p16 overexpression, we reported clinicopathologic features, immunohistochemical results for melanocytic markers and CCRM, and mutational landscape investigated with a next-generation sequencing (NGS) panel. In cases with zonal p16 overexpression, the immunohistochemical assessment for melanocytic markers and CCRM, as well as the NGS analysis have been performed in both components {with and without p16 overexpression [p16(+)c and p16(-)]}. RESULTS: Overexpression of p16 was found in 10/2879 (0.35%) CM [5/10 (50%) diffuse and 5/10 (50%) zonal]. We combined the immunohistochemical results for CCRM and molecular data to classify the cases as follows: a) Group 1 with altered expression of at least one CCRM but no TP53 mutations [3/10 (30%), all with Rb altered/lost]; b) Group 2 with altered expression of at least one CCRM and TP53 mutations [4/10 (40%), all with p53 altered]; c) Group 3 with normal expression of CCRM and no TP53 mutations [3/10 (30%), all with mutations in MAPK pathway genes (NRAS and BRAF)]. In CM with zonal p16 overexpression, the histologic appearance of p16(+)c was heterogeneous, whereas combining CCRM profiles and molecular data the cases could be categorized as follows: a) cases with the same CCRM and molecular profiles in both p16(+)c and p16(-)c; b) cases with p16(+)c showing additional genetic mutations and/or modifications of CCRM expression. CONCLUSIONS: p16 overexpression is a rare event, occurring in advanced-stage, clinically- and histologically-heterogeneous CM. These lesions may be classified into three different groups based on CCRM expression and mutational profiles (including TP53 mutation). The analysis of CM with zonal p16 overexpression suggests that, at least in a subset of cases, this phenomenon could represent a sign of "molecular progression" due to the acquisition of additional genetic mutations and/or modifications of the CCRM profile.

TAMs PD-L1(+) in the reprogramming of germ cell tumors of the testis.

BACKGROUND: In recent years, several studies focused on the process of reprogramming of seminoma (S) cells, which regulates the transition from pure S (P-S) to S component (S-C) of mixed germ cell tumors of the testis (GCTT) and finally to embryonal carcinoma (EC) and other nonseminomatous GCTT (NS-GCTT). The accepted pathogenetic model is driven and regulated by cells (macrophages, B- and T-lymphocytes) and molecules of the tumor microenvironment (TME). Herein, we tested a series of GCTT with double staining (DS) for CD68-PD-L1 to evaluate tumor-associated macrophages (TAMs) expressing programmed death-ligand 1 (PD-L1) [TAMs PD-L1(+)] and clarify if these cells may be involved in establishing the fate of GCTT. METHODS: We collected 45 GCTT (comprising a total of 62 different components of GCTT). TAMs PD-L1(+) were evaluated with three different scoring systems [TAMs PD-L1(+)/mm2, TAMs PD-L1(+)/mm2H-score, TAMs PD-L1(+) %], and compared using pertinent statistic tests (Student's t-test and Mann-Whitney U test). RESULTS: We found that TAMs PD-L1(+) values were higher in S rather than EC (p = 0.001, p = 0.015, p = 0.022) and NS-GCTT (p < 0.001). P-S showed statistically significant differences in TAMs PD-L1(+) values compared to S-C (p < 0.001, p = 0.006, p = 0.015), but there were no differences between S-C and EC (p = 0.107, p = 0.408, p = 0.800). Finally, we found statistically significant differences also in TAMs PD-L1(+) values between EC and other NS-GCTT (p < 0.001). CONCLUSIONS: TAMs PD-L1(+) levels gradually decrease during the reprogramming of S cells {P-S [(high values of TAMs PD-L1(+)] → S-C and EC [(intermediate values of TAMs PD-L1(+)] → other NS-GCTT [(low values of TAMs PD-L1(+)], supporting a complex pathogenetic model where the interactions between tumor cells and TME components [and specifically TAMs PD-L1(+)] play a key role in determining the fate of GCTT.

PRAME Expression in Mucosal Melanoma of the Head and Neck Region.

PRAME (PReferentially expressed Antigen in MElanoma), a cancer-testis antigen expressed in normal and neoplastic tissues with several functions, proved to be a useful diagnostic tool in the differential diagnosis between benign and malignant melanocytic lesions. The current study aims to perform PRAME stain on a retrospective case series of mucosal melanocytic tumors of the head and neck region to compare 3 different scores and evaluate the most reliable one in this diagnostic set. Immunohistochemical analysis for PRAME was performed in 54 benign and malignant mucosal melanocytic tumors of the head and neck region collected from 41 patients. The best-performing cutoff of PRAME-positive cells (nuclear stain) to differentiate benign and malignant mucosal melanocytic tumors of the head and neck region is that proposed by Raghavan and colleagues (<60%/≥60% of PRAME-positive cells), with 100% and 77.8% of benign lesions and malignant tumors respectively correctly identified. Applying this score, PRAME stain showed the best results (sensitivity, specificity, accuracy, and positive and negative predictive values) for the diagnosis of head and neck melanocytic tumors. However, a subset of PRAME-negative malignant tumors was identified, especially located in the palatal area (hard and soft palate). Finally, high PRAME expression (≥60%) was associated with specific sites (nasal cavity/nasal septum/turbinates nasopharynx, and the maxillary sinus), nodular histotype, and female sex.

H&E and OCT4/CD34 for the assessment of lympho-vascular invasion in seminoma and embryonal carcinoma.

BACKGROUND: Lymphovascular invasion (LVI) is a relevant prognostic factor in germ cell tumors of the testis (GCTT), and it is included in the pT stage. However, its detection on hematoxylin and eosin (H&E) slides is very challenging, and previous studies reported fair to moderate inter-observer agreement among dedicated uropathologists. In the present study, we tested H&E and a recently developed in-house double staining for OCT4/CD34 to detect LVI in GCTT. METHODS: Nine authors [5 non-uropathologists and 4 uropathologists] independently evaluated 34 consecutive and retrospectively enrolled cases of GCTT. We assessed the inter-observer agreement (Fleiss's Kappa) with both H&E and OCT4/CD34. Besides, we compared the consensus diagnosis on both H&E and OCT4/CD34-stained sections with the original diagnosis to evaluate the pT re-staging (McNemar test) and identify the sources of disagreement. RESULTS: The inter-observer agreement among uropathologists plus non-uropathologists was fair with both H&E (KF=0.398; p < 0.001) and OCT4/CD34 (KF=0.312; p < 0.001). OCT4/CD34 (KF=0.290; p < 0.001) slightly reduces the inter-observer agreement compared to H&E (KF=0.321; p < 0.001) for non-uropathologists; in contrast, OCT4/CD34 (KF=0.293; p < 0.001) significantly reduces the inter-observer agreement compared to H&E (KF=0.529; p < 0.001) for uropathologists, changing it from moderate to fair. Consensus diagnosis with H&E modified the LVI status of the original diagnosis in 8/34 (23.5 %) cases (p: 0.070), with pT re-staging in 2/34 (5.9 %) cases (p: 0.500). Consensus diagnosis with OCT4/CD34 modified the LVI status of the original diagnosis in 8/34 (23.5 %) cases (p: 0.289), with pT re-staging in 3/34 (8.8 %) cases (p: 0.250). The consensus diagnosis with OCT4/CD34 modified the consensus diagnosis with H&E in 8/34 (23.5 %) cases (p: 0.727), and these findings resulted in pT-restaging in 3/34 (8.8 %) cases (p: 0.500). The sources of disagreement among uropathologists were: H&E [artefactual clefts misinterpreted as LVI in 4/6 (66.7 %) cases and true foci of LVI misinterpreted as clusters of histiocytes within the vessels in 2/6 (33.3 %) cases], OCT4/CD34 [artefactual clefts misinterpreted as LVI in 2/8 (25 %) cases, true LVI misinterpreted as artefactual clefts in 2/8 (25 %) cases or floaters in 4/8 (50 %) cases]. CONCLUSIONS: OCT4/CD34 does not improve the inter-observer agreement for the assessment of LVI in OCT4(+) GCTT. Consensus diagnosis with H&E modifies the LVI status in a significant number of cases, resulting in changes of the pT stage in a relatively small subgroup. Consensus diagnosis with OCT4/CD34 provides little additional benefit since it cannot exclude mimickers of LVI such as floaters and artefactual clefts. These results argue against the adoption of this diagnostic tool for the routine assessment of OCT4(+) GCTT.

Primary pulmonary T-cell lymphoproliferative disorders with a limited-stage, low proliferative index, and unusual clinical behavior: two cases of a rare occurrence.

Extranodal T-lymphoproliferative disorders or T-cell lymphomas (TLPD) are classified according to the WHO Classification (4th and upcoming 5th editions) (Swerdlow et al., IARC Press 1; Alaggio et al., Leukemia 36(7):1720-1748, 2) and to the International Consensus Classification Update (Campo et al., Blood 140(11):1229-1253, 3) upon several morphologic, phenotypic, and genetic features. None of those at present included has been characterized by primary pulmonary onset. We herein present two such cases which, to the best of our knowledge, have not been previously reported and that might represent another variant of T-cell proliferation at mucosal sites. The two cases share similar histological and phenotypic features, suggesting an origin from CD4 + effector memory T cells with the expression of a CD279/PD-1 antigen. They are both monoclonal, harbor few mutations, and show no disease progression outside the lung. They only differ concerning the local extension of the process and clinical setting. The two cases are examples of so far unreported primary pulmonary TLDP, with limited stage and low proliferative index. A possible relationship with a local yet unknown inflammatory trigger that might have favored the development of the T-cell clone cannot be ruled out.

Yolk sac tumor of postpubertal-type does not exhibit immunohistochemical loss of SMARCB1/INI1 and SMARCA4/BRG1 but choriocarcinoma?

The recently described SWI/SNF complex-deficient sinonasal carcinoma (SMARCB1 & SMARCA4) may exhibit a yolk sac-like morphology. Tumors with similar features (yolk sac-like histology combined with the immunohistochemical loss of SMARCB1/INI1 and/or SMARCA4/BRG1) have also been described in other sites, such as the female genital tract. In this study, we immunohistochemically assessed SMARCB1/INI1 and SMARCA4/BRG1 expression to evaluate if these proteins could be involved in the pathogenesis of testicular yolk sac tumors of postpubertal type (YSTpt). Specifically, we analyzed a retrospective case series comprising pure YSTpt and mixed germ cell tumors of the testis (GCTT) with YSTpt components. In the present study, no testicular YSTpt showed loss of SMARCB1/INI1 (0/24, 0%) or SMARCA4/BRG1 (0/24, 0%). However, testicular choriocarcinoma (CHC) and isolated syncytiotrophoblast cells (iSTCs) demonstrated abnormal staining patterns for SMARCA4/BRG1 [CHC: 4/4 (100%); iSTCs: 12/12 (100%), respectively], including focal or diffuse loss of expression in a subset of cases. The results of our study suggest that functional loss of SMARCA4/BRG1 represents a recurrent event that may be relevant for the pathogenesis of a subset of testicular CHC.

Epigenomic and somatic mutations of pituitary tumors with clinical and pathological correlations in 111 patients.

OBJECTIVE: To profile clinically non-aggressive and aggressive pituitary adenomas (PAs)/pituitary neuroendocrine tumours (PitNETs) and pituitary carcinomas for somatic mutations and epigenetic alterations of genes involved in cell proliferation/differentiation, microRNAs (miRNA)/long noncoding RNA (LncRNA)-post-transcriptional regulators and therapy targets. DESIGN: Retrospective observational study. PATIENTS AND MEASUREMENTS: A total of 64 non-aggressive and 41 aggressive PAs/PitNETs and 6 pituitary carcinomas treated by endoscopic surgery with ≥1-year follow-up were included. Somatic mutations of 17 genes and DNA methylation of 22 genes were assessed. Ten normal pituitaries were used as control. RESULTS: We found at least one mutation in 17 tumours, including 6/64 non-aggressive, 10/41 aggressive PAs/PitNETs, and 1/6 pituitary carcinoma. AIP (N = 6) was the most frequently mutated gene, followed by NOTCH (4), and TP53 (3). Hypermethylation of PARP15, LINC00599, ZAP70 was more common in aggressive than non-aggressive PAs/PITNETs (p < .05). Lower levels of methylation of AIP, GNAS and PDCD1 were detected in aggressive PAs/PITNETs than non-aggressive ones (p < .05). For X-linked genes, males presented higher level of methylation of FLNA, UXT and MAGE family (MAGEA11, MAGEA1, MAGEC2) genes in aggressive vs. non-aggressive PAs/PITNETs (p < .05). In pituitary carcinomas, methylation of autosomal genes PARP15, LINC00599, MIR193 and ZAP70 was higher than in PAs/PITNETs, while X-linked genes methylation level was lower. CONCLUSIONS: Somatic mutations and methylation levels of genes involved in cell proliferation/differentiation, miRNA/LncRNA-post-transcriptional regulators and targets of antineoplastic therapies are different in non-aggressive and in aggressive PAs/PitNETs. Methylation profile also varies according to gender. Combined genetic-epigenetic analysis, in association with clinico-radiological-pathological data, may be of help in predicting PA/PitNET behaviour.

SOX2 and PRAME in the "reprogramming" of seminoma cells.

BACKGROUND: In recent years, several studies investigated the complex process called "reprogramming" of seminoma (S) cells. The accepted pathogenetic model is a complex network including SOX2, SOX17, OCT3/4 and PRAME, which modulates the epigenetic transcription of numerous downstream genes and drives a divergent gene expression profile resulting in the transition from pure S (P-S) to S component (S-C) of mixed germ cell tumors of the testis (M-GCTT), and finally to embryonal carcinoma (EC). Herein, we tested a large cohort of GCTT with SOX2 and PRAME to evaluate their expression in the evolutionary steps of GCTT and verify if the modulation in the expression of these two molecules could be relevant for the fate of GCTT. METHODS: We tested 43, 19 and 17 consecutive and retrospectively enrolled cases of GCTT, germ cell neoplasia in situ (GCNIS) and uninvolved background testes (UBT), respectively. SOX2 and PRAME expressions have been evaluated with H-score and compared by adopting the appropriate statistic tests (Student's t-test and Mann-Whitney U test). RESULTS: We found that SOX2 was more expressed by nonseminomatous-GCTT (NS-GCTT) (p < 0.001) and EC (p < 0.001) rather than S; by contrast, PRAME showed an opposite expression profile being expressed by S but not by NS-GCTT (p < 0.001) and EC (p < 0.001). S-C showed different expressions of SOX2 and PRAME compared to both P-S (p = 0.002 and <0.001, respectively) and EC (p < 0.001 and 0.042, respectively), with intermediate values between these latter two categories. GCNIS and UBT showed no expression of SOX2 (scattered positive Leydig cells) but high H-score levels of PRAME. CONCLUSIONS: SOX2 and PRAME are differentially expressed and specularly modulated during the "reprogramming" of S cells [P-S (high levels of PRAME, no expression/low levels of SOX2) → S-C (intermediate levels of PRAME, intermediate levels of SOX2) → EC (no expression/low levels of PRAME, high levels of SOX2)], therefore supporting a complex pathogenetic model where the interactions between these two molecules are crucial in determining the fate of GCTT.

Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis.

Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial-misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the "gold standard" for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department.

Robotic resection of mediastinal left vagus neurofibroma.

A Correction has been published | View Neurogenic tumors represent 10 to 34% of all mediastinal tumors and among them, neurofibroma originating from the vagus nerve are rare entities. We present a case of a neurofibroma with cystic degeneration originating from the left branch of the vagus nerve in a 27-year-old man without von Recklinghausen disease. A complete robotic resection of the mediastinal mass has been performed, with amputation of the vagus nerve enclosed in the mass. The postoperative course was uneventful and the patient was discharged in two days.

Could double stain for p53/CK20 be a useful diagnostic tool for the appropriate classification of flat urothelial lesions?

BACKGROUND: The differential diagnosis between flat urothelial lesions [reactive urothelial atypia (RUA), atypia of unknown significance (AUS), urothelial dysplasia (UD) and carcinoma in situ (CIS)] has relevant prognostic and therapeutic implications. This crucial distinction could be very challenging but it is currently performed on hematoxylin and eosin (H&E) slides, with a great amount of partially discordant and/or not conclusive findings of the potential adjunctive role of immunohistochemistry. Herein, we tested double staining (DS) for p53/CK20 to verify if p53(+) cells, CK20(+) cells and double-positive cells (DPCs) are differentially expressed among these lesions and if p53/CK20 could be a useful tool in this diagnostic setting. METHODS: We tested 50, 9, 36 and 29 consecutive and retrospectively enrolled cases of RUA, AUS, UD and CIS, respectively. p53(+) cells, CK20(+) cells and DPCs were evaluated and compared by adopting the appropriate statistic tests (Mann-Whitney U and Kruskal-Wallis tests). RESULTS: We found that p53(+) cells (p = 0.000), CK20(+) cells (p = 0.000) and DPCs (p = 0.000) showed statistically significant differences among the different flat urothelial lesions. Besides, when dichotomized, both CIS and RUA are easily differentiable from their histological mimickers adopting all these markers; by contrast, AUS and UD did not reach statistically significant differences able to differentiate them from each other [p53(+) cells, p = 0.123; CK20(+) cells, p = 0.567; DPCs, p = 0.409], except if compared to CIS [AUS VS CIS: p53(+) cells, p = 0.013; CK20(+) cells, p = 0.000; DPCs, p = 0.000; UD vs CIS: p53(+) cells, p = 0.000; CK20(+) cells, p = 0.000; DPCs, p = 0.000]. CONCLUSIONS: p53(+) cells, CK20(+) cells and DPCs are differently expressed by flat urothelial lesions and p53/CK20 could be a time- and money-saving tool for the appropriate management of these lesions if applied to a routine scenario.

The EORTC protocol for sentinel lymph node biopsy (SLNB) reveals a high number of nodal nevi and a strong association with nevus-associated melanoma.

BACKGROUND: The diagnosis of nodal nevi (NN) is challenging as they mimic melanoma metastases (MM), with a detection rate mostly ranging between 1% and 11% in sentinel lymph node biopsy (SLNB). Herein, we assessed the incidence of NN and the association with the clinical-pathological features of primary melanoma, adopting the updated European Organisation for Research and Treatment of Cancer (EORTC) protocol for SLNB. METHODS: All cases of paired melanoma and SLNB were retrospectively evaluated (April 2019-May 2020). Appropriate statistical tests were adopted, with significant variables included in the logistic regression model. RESULTS: 81 patients and a total of 186 lymph nodes (LNs) were included. Eleven patients had only NN and 4 had both NN and MM (18.5%); 29 LNs (15.6%) showed at least one NN and 12 (6.5%) showed more than one NN (a total amount of 43 NN was detected). All NN and none MM stained for p16. NN were associated with age < 60 years (p: 0.042), no ulceration (p: 0.025) and nevus-associated melanoma (NAM) (p: 0.018), with this latter being the only predictor at the logistic regression model (p: 0.022). CONCLUSIONS: The updated EORTC protocol shows a high number of NN and highlights a strong association with NAM.

Interobserver agreement of PD-L1 (SP263) assessment in advanced NSCLC on cytological smears and histological samples.

BACKGROUND: The PD-L1 assessment is mandatory for the selection of patients affected by advanced non-small-cell lung cancer (NSCLC) who can benefit from the PD-1/PD-L1 checkpoint inhibitors therapy. Previous studies tested PD-L1 on cytological smears to evaluate this sample as an alternative to formalin-fixed paraffin-embedded (FFPE) ones, but several critical issues needed to be clarified. AIM: We evaluated the cyto-histological agreement (CHA) and the PD-L1 interobserver agreement (IrOA) among three different pathologists (Path1, Path2, Path3) on 160 paired cytological smears and histological samples of advanced NSCLC. RESULTS: With the cut-off of < 50%/≥ 50%, CHA resulted good for Path1 (Cohen's k: 0.702) and Path3 (Cohen's k: 0.731), moderate for Path2 (Cohen's k: 0.576) adopting the same cut-off, the IrOA was moderate (ICC 0.72 [95% CI: 0.63-0.78]) for smears and good for histological samples (ICC 0.85 [95% CI: 0.80-0.85]). CONCLUSION: With a cut-off system of < 50%/≥ 50%, PD-L1 assessment shows moderate to good CHA and exhibited moderate IrOA on smears and good IrOA on FFPE. As result, PD-L1 assessment should be improved on cytological smears as well as could be a suitable alternative for patients without FFPE samples and not eligible for pembrolizumab, adopting a cut-off of < 50%/≥ 50%; presumably, an appropriate pathologist training could further improve the reproducibility.

Hematoxylin and eosin or double stain for CD34/SOX10: Which is better for the detection of lymphovascular invasion in cutaneous melanoma?

BACKGROUND: Lymphovascular invasion (LVI) is considered an unfavorable prognostic factor in cutaneous melanoma (CM). However, its detection by hematoxylin and eosin (H&E) is challenging, with discordant data about its association with clinical-pathological features and no previous studies investigating the inter- (IrOA) and intra-observer (IaOA) agreement. Herein, we tested H&E and double staining (DS) for CD34/SOX10 to detect the LVI in a cohort of 92 CMs, evaluating the IrOA, the IaOA, and the association with the other clinical-pathological features. METHODS: Five authors independently evaluated 92 consecutive and retrospectively enrolled cases of CMs. We assessed the IrOA (Fleiss's Kappa/FK and intraclass correlation coefficient/ICC) and the IaOA (Cohen's Kappa/CK) with both H&E and CD34/SOX10. Furthermore, we compared the LVI assessment with the two stains and analyzed the association with other clinical-pathological features [χ2 tests for dichotomous and categorical data; Student t-test (normal distribution) and Mann-Whitney U-test (non-normal distribution) for continuous data]. RESULTS: The IrOA was almost identical with H&E (FK=0.446; ICC=0.805) and CD34/SOX10 (FK=0.454; ICC=0.810); by contrast, the IaOA was higher with H&E for one pathologist (CK: 0.809) and with CD34/SOX10 for the other one (CK: 0.563). Applying previously defined criteria, LVI was detected in 10 (9.2%) and 11 (10.1%) cases with H&E and CD34/SOX10, respectively (p = 1.000). Both H&E and CD34/SOX10 were significantly associated with vertical growth phase (H&E, p: 0.014; CD34/SOX10, p: 0.010), mitosis ≥ 1/mm2 (H&E, p: 0.000; CD34/SOX10, p: 0.004), pT (H&E, p: 0.000; CD34/SOX10, p: 0.001), Breslow thickness (H&E, p: 0.000; CD34/SOX10, p: 0.001), and lymph node and/or distant metastasis (H&E, p: 0.005; CD34/SOX10, p: 0.000); only H&E was associated with ulceration (p: 0.002) and distant metastasis (p: 0.000), conversely, only CD34/SOX10 was associated with lymph node metastasis (p: 0.003). CONCLUSIONS: CD34/SOX10 does not improve the IrOA and the IaOA of the LVI assessment in CM; furthermore, H&E and CD34/SOX10 show a similar profile of association with the other unfavorable clinical-pathological features of CM. As result, CD34/SOX10 could be a redundant diagnostic tool if applied for the prognostic characterization of not-selected CM in a routine diagnostic scenario.