Accurate classification of lung cancer into primary and metastatic carcinomas is critical for treatment approaches. Immunohistochemistry (IHC) has always been pivotal in unveiling the diverse cell differentiation lineages present in lung cancer by using specific biomarkers such as TTF1 and p63/p40, which closely reflect the relationship between genotype and phenotype.. A retrospective cross-sectional study was conducted to evaluate 57 Tru-Cut biopsies over two years, from 2020-2022. Tumour morphology was evaluated, and IHC for TTF-1, Napsin A, CK-7, P-63, P-40, and CD-56 was performed in two steps. Of the lung cancer cases, 58.5% were adenocarcinoma (ADC), 24.5% were squamous cell carcinoma (SCC), 9.4% were small cell carcinoma, and 7.5% were poorly differentiated carcinoma. TTF1 stain had sensitivity and specificity of 78.9% and 50% in 33 cases of ADC, respectively, while CK7 and Napsin A had 100% sensitivity. P63 stain had 77% sensitivity and 50% specificity in 15 cases of SCC, while P-40 had 100% sensitivity. The CD56 stain was 100% sensitive in five cases of small cell carcinoma. IHC staining on small lung biopsies allows accurate sub-classification of poorly differentiated lung cancers; however, there is still significant variability. Surgical resection specimens can be further classified due to architectural features that biopsies lack. Morphological findings would be beneficial in the development of an algorithm for sub-classifying lung carcinoma using a variety of markers.

Background: Prompt detection of acute ischemic stroke is essential for effective treatment and improved clinical outcomes. Diffusion-weighted imaging (DWI) and non-contrast computed tomography (NCCT) are commonly used imaging tools; however, their relative diagnostic accuracy within the hyperacute phase (≤ 6 hours) requires further clarification. Objectives: This study aimed to evaluate the diagnostic accuracy of NCCT compared with DWI magnetic resonance imaging (MRI) as the reference standard in patients presenting within 6 hours of symptom onset. Methods: This prospective diagnostic accuracy study included 84 consecutive eligible cases presenting with symptoms suggestive of acute ischemic stroke within 6 hours of onset. All patients underwent NCCT followed by DWI MRI. The DWI MRI was predefined as the sole reference standard. Neuroimaging was evaluated by an independent radiologist blinded to clinical data and to the findings of the alternate imaging modality. Diagnostic performance of NCCT was calculated using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall accuracy, and 95% confidence intervals (CIs). Results: Among the 84 patients, DWI identified 53 patients as positive for acute ischemic stroke. NCCT correctly identified 45 of these 53 DWI-positive cases, yielding a sensitivity of 84.9% (95% CI: 72.4% - 92.1%). It also correctly identified 24 of 31 DWI-negative cases, resulting in a specificity of 77.4% (95% CI: 59.8% - 89.4%). There were 8 false-negative cases (15.1%) and 7 false-positive cases (22.6%). Overall diagnostic accuracy of NCCT was 82.1% (69/84). Conclusions: Diffusion-weighted imaging demonstrated higher sensitivity than NCCT for detecting hyperacute ischemic stroke. While NCCT remains essential for rapid exclusion of intracranial hemorrhage, DWI may provide complementary diagnostic value when available. These findings should be interpreted cautiously and require confirmation in larger multicenter studies.