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Recurrent pericardial effusion poses a diagnostic challenge, especially in young patients. We present a case of a 22-year-old female who experienced recurrent pericardial effusion and cardiac tamponade. Despite initial treatment with anti-tubercular drugs and prednisolone, the patient had a relapse of symptoms, necessitating further investigation. Imaging studies revealed massive pericardial effusion with septations, suggestive of constrictive pericarditis with impending cardiac tamponade. To establish a definitive diagnosis, the patient underwent an FDG PET-CT scan after adhering to a specific dietary regimen. The scan revealed an ill-defined mediastinal mass with high metabolic activity, along with a gross pericardial effusion showing metabolic activity in the periphery and septations. Subsequent biopsy of the mediastinal mass confirmed a diagnosis of high-grade sarcoma.Primary malignant cardiac tumors are rare, and their prognosis is generally poor due to limited treatment options. While echocardiography and MRI are commonly used imaging techniques, FDG PET-CT is not routinely employed for evaluating cardiac tumors. However, in this case, FDG PET-CT played a crucial role in identifying the mediastinal mass and confirming the diagnosis.Early detection and accurate diagnosis of cardiac tumors are vital for initiating appropriate treatment strategies. Further studies are needed to explore the utility of FDG PET-CT in the evaluation of cardiac tumors, especially in cases of recurrent pericardial effusion.
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ABSTRACT: A primary epithelioid angiosarcoma of the pericardium is a rare soft tissue malignancy. This report describes a young adult woman who presented with progressive dyspnea and pericardial effusion. She was found to have pericardial mass on imaging along with extensive myocardial infiltration. The biopsy of the mass revealed epithelioid angiosarcoma, which was CD34 and CD31-immuno-positive. Due to unresectable disease, she was given a trial of immunotherapy followed by conventional chemotherapy. She showed partial response on interim assessment, but progressed soon after the completion of six cycles and succumbed to her rapidly progressive illness within nine months of diagnosis. This report discusses the diagnostic and therapeutic challenges faced while managing this disease of aggressive tumor biology.
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Renal transplant recipients are prone to a high risk of subsequent upper tract urothelial carcinoma, occurring in both native and transplant ureters. We report a rare case of adenocarcinoma with yolk sac differentiation of the transplant ureter, which was managed successfully with transplant ureterectomy and pyelovesicostomy, thereby salvaging the functioning transplant kidney.
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Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.
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Bhupesh GuleriaAims Adolescent and young adults (AYAs), children with cancer, and their guardians have unique psychosocial morbidities adversely effecting quality of life (QOL). This is measurable using patented tools. We analyzed epidemiological and clinicopathological patterns of solid organ cancers in this subgroup. We also assessed psychosocial morbidity and changes in QOL faced by them. Methods All patients aged 2 to 39 years, newly diagnosed with cancer from April 2017 to March 2019 were included. Clinical history, diagnosis, staging, treatment, outcomes, and follow-up were recorded. The National Comprehensive Cancer Network (NCCN) distress thermometer and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C-30) were used to assess psychosocial morbidity of AYAs, children ≥ 12 years, and parents of children < 12 years. Pediatric Quality of Life Inventory (Peds QL) version 3.0 was used for children < 12 years. Data was analyzed using descriptive statistics. Results A total of 571 patients (512 AYAs, 59 children) were enrolled. Median age was 30 years with male predominance (58.1%). Most cases (98.6%) were absent from school or work. Carcinoma breast was the most common in females (29.3%) and non-Hodgkin lymphoma in males (12.6%). 91.06% had overall NCCN distress score ≥ 4. Also, 73.81 and 79.49% had "quite a bit" or "very much" responses on functional and symptom scales, respectively, in EORTC QLQ C-30 questionnaire. Peds QL version 3.0 revealed total score ranging from 276 to 523 for each patient. Conclusion AYAs and children with cancer are extremely vulnerable to psychological stress and morbidity. Use of well-established tools help in assessing their mental status and timely psychiatric referral can be initiated.
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Solid Papillary Carcinoma (SPC) of the breast is a rare tumor with an incidence of less than 1%, mainly affecting elderly females. It is morphologically characterized by well-defined nodules with low-grade nuclear features associated with fibrovascular cores and shows neuroendocrine differentiation. SPC can be in-situ or invasive but has a favorable prognosis. It is a morphological mimicker of some pre-malignant conditions leading to its frequent misdiagnosis. An appropriate immunohistochemical (IHC) panel workup helps in distinguishing this tumor from its various morphological mimics. In this report, we present one such case of SPC with a small focus of invasion, reviewing the literature.
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Solid Papillary Carcinoma (SPC) of the breast is a rare tumor with an incidence of less than 1%, mainly affecting elderly females. It is morphologically characterized by well-defined nodules with low-grade nuclear features associated with fibrovascular cores and shows neuroendocrine differentiation. SPC can be in-situ or invasive but has a favorable prognosis. It is a morphological mimicker of some pre-malignant conditions leading to its frequent misdiagnosis. An appropriate immunohistochemical (IHC) panel workup helps in distinguishing this tumor from its various morphological mimics. In this report, we present one such case of SPC with a small focus of invasion, reviewing the literature.
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Humanos , Masculino , Feminino , Idoso , Carcinoma Papilar/patologia , Neoplasias Unilaterais da Mama/patologia , Erros de DiagnósticoRESUMO
The advent of immune-checkpoint inhibitors (ICI) in modern oncology has significantly improved survival in several cancer settings. A subgroup of women with breast cancer (BC) has immunogenic infiltration of lymphocytes with expression of programmed death-ligand 1 (PD-L1). These patients may potentially benefit from ICI targeting the programmed death 1 (PD-1)/PD-L1 signaling axis. The use of tumor-infiltrating lymphocytes (TILs) as predictive and prognostic biomarkers has been under intense examination. Emerging data suggest that TILs are associated with response to both cytotoxic treatments and immunotherapy, particularly for patients with triple-negative BC. In this review from The International Immuno-Oncology Biomarker Working Group, we discuss (a) the biological understanding of TILs, (b) their analytical and clinical validity and efforts toward the clinical utility in BC, and (c) the current status of PD-L1 and TIL testing across different continents, including experiences from low-to-middle-income countries, incorporating also the view of a patient advocate. This information will help set the stage for future approaches to optimize the understanding and clinical utilization of TIL analysis in patients with BC.
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Thymomas are the most frequent adult mediastinal cancers. Their etiology is unknown and their pathogenesis poorly understood. Racial, ethnic and environmental factors influence tumorigenesis in many cancers, but their role in thymomas remains unclear to date. In this study that included pretreatment thymoma cases from India and Germany (n = 37 and n = 77, respectively) we compared i) the prevalence of the thymoma-specific chromosome 7 c.74146970T > A mutation of the GTF2I gene in type A and AB thymomas; ii) epidemiological features; and iii) the frequency of myasthenia gravis (MG). Due to a known predominance of GTF2I mutation in A and AB histotypes, we included only a marginal number of type B thymomas as a control group in both cohorts. While the distribution of histological types between the cohorts was similar (p = 0.1622), Indian patients were strikingly younger (p < 0.0001; median age 50 vs. 65 years) and showed significantly lower tumour stage (Masaoka-Koga stage I) at primary diagnosis (p = 0.0005) than the German patients. In patients with known MG status (n = 17 in Indian and n = 25 in German cohort), a clear trend towards more frequent MG was observed in the Indian group (p = 0.0504; 48 vs. 82%). The prevalence of the GTF2I mutation (analysed in n = 34 Indian and n = 77 German patients) was identical in the two cohorts. We conclude that racial-ethnic and environmental factors do not significantly influence the most common molecular feature of thymomas but may have an impact on the timing of clinical presentation.
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Timoma/genética , Neoplasias do Timo/genética , Fatores de Transcrição TFII/genética , Adulto , Idoso , Feminino , Alemanha/epidemiologia , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Mutação , Miastenia Gravis/patologia , Fatores Raciais , Timoma/epidemiologia , Timoma/etnologia , Timoma/patologia , Neoplasias do Timo/epidemiologia , Neoplasias do Timo/etnologia , Neoplasias do Timo/patologiaRESUMO
Pituicytoma is a distinct sellar or supracellar tumor which originates from specialized glial cells of neurohypophyses and infundibulum known as pituicytes. Because of its sellar location patients present with headache, visual disturbance, and endocrine abnormalities. Pituicytoma is difficult to diagnose on neuroimaging as radiological features overlap with other more common tumors of this region. Thus, diagnosis is established by histopathology and immunohistochemistry of resected tumor only. Pituicytomas are composed of bipolar spindle cells arranged as fascicles and are immunoreactive for TTF-1, S100p, and vimentin. These tumors are extremely rare and only around 70 published cases are known in literature. We report a case of suprasellar SOL in a 58-year-old male who presented with headache and gradual visual deterioration in both eyes. He was diagnosed as a case of pituicytoma based on light microscopy findings and immunohistochemical expression of TTF-1, vimentin, S100p, and bcl-2.
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Glioma/diagnóstico , Neoplasias Hipofisárias/classificação , Neoplasias Hipofisárias/diagnóstico , Biomarcadores Tumorais/genética , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação a DNA/genética , Diagnóstico Diferencial , Genes bcl-2/genética , Glioma/classificação , Glioma/genética , Cefaleia/etiologia , Técnicas Histológicas , Humanos , Imuno-Histoquímica/métodos , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Neoplasias Hipofisárias/genética , Fatores de Transcrição/genética , Vimentina/genéticaRESUMO
BACKGROUND: Lung adenocarcinomas present as tight clusters and three-dimensional balls in effusion specimens. Unlike carcinomas of breast and stomach where singly lying malignant cells are seen in effusion samples, lung adenocarcinomas usually show cohesive morphology. This single-cell pattern may also be confused with reactive mesothelial cells. We studied the frequency of pulmonary adenocarcinoma with single-cell pattern cytomorphology in pleural effusion specimens. MATERIALS AND METHODS: All cases reported as either suspicious or positive for malignancy on pleural effusion cytology (PFC) over the past 1 year were retrieved. The clinical details were obtained from requisition forms. Cases with predominant single-cell pattern, clinically suspicious of carcinoma lung were segregated. These were de-stained and immunocytochemistry (ICC) for TTF-1 was performed. RESULTS: Of 103 cases reported as either suspicious or positive for malignancy on PFC, 29 had a predominant single-cell pattern. Of these, 13 (44.8%) were primary lung carcinoma. The rest were metastasis from ovary (5; 17.2%), breast (2; 6.9%), stomach (2; 6.9%), lymphoma (1; 3.5%), and Ewing's sarcoma (1; 3.5%). Five (17.2%) were those with unknown primary. All cases of lung carcinoma were positive for TTF-1 ICC. CONCLUSION: Single-cell pattern of pulmonary adenocarcinoma is commoner than popularly believed. This pattern may be difficult to differentiate from carcinoma cells of other sites as well as from reactive mesothelial cells. A high degree of suspicion is therefore needed to perform relevant ICC to clinch the correct diagnosis.
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Adenocarcinoma de Pulmão/patologia , Neoplasias Pulmonares/patologia , Derrame Pleural Maligno/patologia , Adenocarcinoma de Pulmão/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma/metabolismo , Carcinoma/patologia , Citodiagnóstico/métodos , Proteínas de Ligação a DNA/metabolismo , Humanos , Imuno-Histoquímica/métodos , Neoplasias Pulmonares/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Derrame Pleural Maligno/metabolismoRESUMO
BACKGROUND: Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is the most heterogeneous subcategory of the Bethesda system for thyroid cytopathology with laid down permissible limits of frequency and risk of malignancy (ROM). Due to differences in thyroid clinical practice worldwide, variations have been found in frequency, resection rates (RR) and ROM. Therefore, this systematic review and meta-analysis of AUS/FLUS across different regions was conducted and comparison of data from India was done with the rest of Asia and the West. METHODS: We searched PubMed and Google search engines from January 2009-Dec 2019 using terms "AUS Thyroid" and "FLUS Thyroid". Meta-analysis was performed using DerSimonian-Laird method and 95% confidence intervals were calculated using random effects model. Independent samples t-test was used to compare frequency, RR, and ROM of AUS/FLUS between India, rest of Asia and the West. RESULTS: Out of 15,000 studies on internet, 60 (18 Indian, 12 Asian and 30 Western) were included. Total aspirates were 201,657; 14,279 Indian, 62,448 Asian, 124,930 Western. Pooled estimates were: frequency 7.3% (6.3-8.3%), RR 41.9% (37.4-46.6%), ROM 33.3% (26.8-39.9%). Pooled prevalence of rate did not vary significantly across the three regions. Pooled prevalence of RR was highest in India (52.9%) and lowest in rest of Asia (26.5%); of ROM was highest in Asia (45.9%), lowest in the West (26.3%) (P<0.01). Statistical analysis demonstrated publication bias, limited to Indian and Western studies. Papillary thyroid carcinoma was the most common surgical diagnosis (87.9%; 1,082/1,231). CONCLUSIONS: This meta-analysis showed differences in thyroid clinical practice followed in India, rest of Asia and the West. Although pooled prevalence of rate of AUS/FLUS was similar across the three, pooled RR and ROM varied. AUS/FLUS nodules were more frequently resected in Indian and Western studies than in rest of Asia. ROM was higher than recommended values in all three areas, being intermediate for India.
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High-grade neuroendocrine tumors (HGNET) have distinctive tumor biology/behaviour. Newer modalities of treatment (immunotherapy) for them have been included in recent NCCN guidelines. Detection of programmed death receptor-ligand 1 (PD-L1) expression by immunohistochemistry have made easy identification of patients eligible for immunotherapy. We aimed to ascertain expression of PD-L1 on small cell and large cell neuroendocrine carcinomas of lung and review existing literature. Eighty-five cases of HGNET lung (primary/metastatic), were retrieved and reviewed. Immunostaining for PD-L1 using clone SP263 was done. Any amount/intensity of membranous staining of > = 1% tumor cells was cut-off for positivity. Previously published studies using Google and/Pubmed search engines were reviewed. Of 85 cases, 70 were small-cell lung cancer (SCLC), 11 large-cell neuroendocrine carcinoma (LCNEC) and 4 combined SCLC. Median age was 46.5 years with male preponderance. No PD-L1 expression was seen in 91.6% cases. The 7 positive cases were 4 LCNEC, 2 SCLC and 1 combined SCLC. The percentage positivity varied from 1-100%; lower percentage positivity was seen in SCLC. PD-L1 expression on immune cells was seen in 31.3% cases. Sixteen studies evaluating 1992 NET were found; E1L3N PD-L1 clone was commonly used clone. PD-L1 positivity was associated with better prognosis in most studies. There are only a few studies available in literature related to PDL1 expression in high grade neuroendocrine carcinomas of lung. In general, PD-L1 positivity is highly variable and seen in lower percentage of these tumors. With the recent approval of immunotherapy, biomarkers other than PD-L1 should also be investigated in these tumors.
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Antígeno B7-H1/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Neuroendócrino/patologia , Imuno-Histoquímica/métodos , Neoplasias Pulmonares/patologia , Carcinoma de Pequenas Células do Pulmão/patologia , Adulto , Idoso , Carcinoma Neuroendócrino/metabolismo , Feminino , Seguimentos , Humanos , Neoplasias Pulmonares/metabolismo , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/metabolismoRESUMO
OBJECTIVE: Granulosa cell tumors (GCT) are low-grade malignant sex cord-stromal tumors (SCST) with late metastasis/recurrences and long disease-free periods. We performed a clinicopathological evaluation of GCT to ascertain features having prognostic impact. MATERIALS AND METHODS: All cases of GCT of ovary from January 2006 to December 2018 were assessed for architectural patterns, nuclear grooves, and Call-Exner bodies. Each feature was graded on frequency of occurrence: not present (0)-very frequent (3). Anisonucleosis, necrosis, and inflammation were noted. Cases were grouped on mitotic count; <10 mitosis/10 High power field (HPF) or >=11 mitoses/10 HPF and Ki-67 index; <10% Ki-67 and >=11% Ki-67. RESULTS: GCT formed 60.1% of SCST. Sixty cases' ages were in the range of 15-78 years (median 45). Clinical details were available in 37. Commonest presentation was abnormal uterine bleeding. Serum CA125 was raised in 16.1% and Inhibin in 58.8%. Seventy percent were in stage I. Disease recurrence was associated with higher stage (P = 0.007). The most frequent pattern was diffuse sheets (47%). Call-Exner bodies were absent in 22.2%. Grooves with score 1, 2, and 3 were seen in 35.8%, 23.5%, and 13.6%, respectively. Anisonucleosis was present in 26.7%, necrosis in 11.1%, and lympho-plasmacytic infiltrate in 43%. Out of total, 93.3% had <10 mitosis/10 HPF and 43.2% had recurrence, most with high Ki-67 (P = 0.064). CONCLUSION: Our study outlines histomorphological spectrum of GCT and emphasizes its frequent occurrence in lower stages with late recurrences. The presence of grooves may indicate granulosa-cell origin. Call-Exner bodies are not a necessity. Histomorphological features are not prognostically important. However, prognostic value of Ki-67 cannot be excluded. Limitation of the study was a small number of cases with follow-up.
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Tumor de Células da Granulosa/patologia , Neoplasias Ovarianas/patologia , Ovário/patologia , Adolescente , Adulto , Idoso , Feminino , Tumor de Células da Granulosa/diagnóstico , Humanos , Inflamação , Pessoa de Meia-Idade , Mitose , Necrose , Recidiva Local de Neoplasia , Prognóstico , Estudos Retrospectivos , Adulto JovemRESUMO
Paediatric mesenchymal tumors of the mediastinum are extremely rare tumors forming approximately 2% of all mediastinal neoplasms. There are subtle differences in the clinical and histomorphological profile of these tumors from their adult counterparts. The management of these tumors in the children is primarily surgical. This review was done to perform a comprehensive analysis of these mesenchymal tumors in the paediatric age group.
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Background & objectives: Thymomas are rare, but most common anterior mediastinal lesions. The histomorphologic spectrum of thymic epithelial tumours (TETs) in Indian population has not been explored in depth. This study was aimed to assess the histomorphology of TETs in the Indian patients and correlate clinical parameters with pathological features. Methods: It was a retrospective study conducted in a tertiary referral hospital in north India. All morphologically confirmed cases of TETs since 2009 were included. Clinical details and histology slides were reviewed using the Modified Masaoka-Koga staging system and WHO 2015 classification. Clinicopathological correlation and survival analysis were done. A comparative review from other published Indian studies was performed. Results: A total of 219 cases of TETs (138 resections and 81 biopsies) were identified. The most common histomorphologic type was B2, and the most frequent stage was I. Types A/AB were common in older age (P<0.01). Clinically, higher stage tumours were found mostly in men (P<0.01), and these were Type B thymomas (P<0.01). Myasthenia gravis was more common in women (P<0.02) and in lower stages (P<0.05). Survival analysis revealed significant association between recurrence and tumour stage. Although thymic carcinoma was diagnosed on biopsy, no resectable case was identified. Interpretation & conclusions: Our findings showed that the thymomas in Indian patients were most commonly Stage I tumours of B2 and AB histotypes. Resected thymic carcinomas were conspicuously absent in our study. More studies need to be done to establish the frequency and biology of TETs from India.
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Recidiva Local de Neoplasia/patologia , Neoplasias Epiteliais e Glandulares/patologia , Timoma/patologia , Neoplasias do Timo/patologia , Adulto , Feminino , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/epidemiologia , Estadiamento de Neoplasias , Neoplasias Epiteliais e Glandulares/epidemiologia , Estudos Retrospectivos , Timoma/epidemiologia , Neoplasias do Timo/epidemiologiaRESUMO
AIMS: The 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) recommends subclassification of atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS) into six subcategories. The present study evaluates the risk of malignancy (ROM) and risk of neoplasm (RON) among these. METHODS: All thyroid aspirates reported as AUS/FLUS over a 4.5-year period, with available histology, were reviewed and subclassified as per TBSRTC. ROM and RON were calculated and compared. RESULTS: Of 2554 thyroid aspirates, 281 (11.0%) were AUS/FLUS. Eighty-one with available histology were evaluated. ROM was 51.8%. Cytologic and architectural atypia (AUS-C&A) was the most prevalent (62.9%), followed by Hürthle cell type (19.6%), AUS-A (11.1%), AUS-not otherwise specified (NOS) (7.4%), cytologic atypia (AUS-C) (4.9%) and atypical lymphoid cells (1.2%). Papillary thyroid carcinoma (PTC) and adenomatous goitre (AG) were the most common histological diagnoses (27% each). On histology, AUS-C had 2/4 PTC and 2/4 AG on histology. AUS-A had 4/9 follicular neoplasm (FN) and 2/9 non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) while AUS C&A had 18/51 PTC, 13/51 AG, 11/51 NIFTP and 5/51 FN. ROM and RON were similar across subcategories, ROM was the highest for AUS-C&A (58.8%), AUS-C (50%) and AUS-NOS (50%). NIFTP reclassification as non-malignant reduced ROM to 35.8% (absolute reduction of 16% and a relative decrease of 31%) with the greatest relative decrease seen in AUS-A (50%), followed by AUS-C&A (37%), and none in others. CONCLUSIONS: AUS/FLUS subcategorisation helped to indicate risk for the more likely neoplasm, whether PTC or FN. ROM was the highest for cases with cytological atypia but did not differ significantly across different subcategories. NIFTP changed the ROM of AUS-A and AUS-C&A, since both NIFTP and FN have microfollicles.
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Centros de Atenção Terciária , Doenças da Glândula Tireoide/patologia , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Criança , Diagnóstico Diferencial , Feminino , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Doenças da Glândula Tireoide/classificação , Doenças da Glândula Tireoide/cirurgia , Glândula Tireoide/cirurgia , Neoplasias da Glândula Tireoide/classificação , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Adulto JovemRESUMO
BACKGROUND: In a significant percentage of patients with small cell lung carcinoma (SCLC), cytology samples represent the only source of tumor tissue. Ancillary immunocytochemistry (ICC) for neuroendocrine markers is an important adjunct for the diagnosis of SCLC. Insulinoma-associated protein 1 (INSM1) is a novel neuroendocrine marker proposed as an economical single-marker alternative to the traditional 3-marker panel of chromogranin, synaptophysin, and CD56. To the authors' knowledge, limited studies have evaluated INSM1 immunohistochemistry (IHC) for the diagnosis of SCLC and reported high sensitivities and specificities. The objective of the current study was to evaluate the sensitivity and specificity of INSM1 ICC on direct smears (DS) from patients with SCLC in comparison with IHC on small biopsies (SBs). METHODS: All available DS and SBs from patients with SCLC who were diagnosed over the previous year were retrieved. Immunostaining for INSM1 was performed on alcohol-fixed DS and formalin-fixed SBs wherever available. A total of 10 DS and SBs from patients with non-small cell lung carcinoma were included for comparison. Nuclear staining for INSM1 in ≥1% tumor cells was interpreted as positive. RESULTS: Among a total of 60 patients with SCLC who were included in the current study, a total of 37 underwent INSM1 IHC on SBs and 36 underwent INSM1 ICC on DS. ICC was noninterpretable in 3 DS due to necrosis. The sensitivity of INSM1 IHC was 97% (36 of 37 cases) whereas the sensitivity of INSM1 ICC was 91% (30 of 33 cases) for the diagnosis of SCLC. Among matched IHC and ICC results available for 11 patients, 91% of cases (10 of 11 patients) demonstrated concordant IHC-ICC staining. All cases of non-small cell lung carcinoma were negative for INSM1 (100% specificity). CONCLUSIONS: INSM1 appears to be a robust and reliable ICC marker for the confirmation of SCLC diagnosis on cytology smears.