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Introduction Although the cytology of effusion fluids is considered a routine laboratory test, it has recently emerged as an essential tool in determining the primary site of origin of carcinoma of unknown primary. The sensitivity for diagnosing malignancy has enhanced with the inclusion of cytospin, cell block (CB), and immunohistochemistry (IHC) to effusion fluid cytology due to the improvement in morphological preservation and good cellular yield. The purpose of this study was to assess the diagnostic yield, sensitivity, specificity, positive predictive value, and negative predictive value of IHC and CB in effusion cytology. Methodology An institution-based cross-sectional study was conducted over a period of six months on 150 cases of effusion fluids submitted for diagnostic purposes. After the preparation of cytospin, the residual amount of centrifuged deposit was mixed with CytoLyt solution, thrombin, and plasma, and CBs were prepared. IHC was applied to the CB. Calretinin was used for mesothelial cells, and BerEP4, TTF-1, ER, WT-1, and CD-X2 were used for the confirmation and origin of malignant cells. Results The mean age of the patients was 51.75 ± 16.63 years. The male-to-female ratio was 1:1.24. Out of 150 cases, 78 were pleural effusions, 68 were peritoneal effusions, and four were pericardial effusions. Out of 150 cases, based on cytological examination alone, 66 (44%) were classified as benign, 27 (18%) as malignant, and 57 (38%) were suspicious for malignancy. When cytology was combined with CB and IHC, the diagnostic yield was increased to benign 95 (63.33%), malignant 48 (32%), and suspicious for malignancy 7 (4.67%). The most common cause of malignant pleural effusion was breast carcinoma in females and lung carcinoma in males. The most common primary tumor in malignant peritoneal effusion was ovarian carcinoma in females and colonic adenocarcinoma in males. The sensitivity and specificity of combined cytology with cell block and IHC were 92.31% and 98.95%, respectively. This combination produced significantly better results (p-value = 0.001) for detecting malignancy and reduced suspicious cases from 38% to 4%. Conclusion CB, in combination with IHC, increases the diagnostic yield and aids in detecting malignancy at an unknown primary site in effusion fluids. Both of these techniques can thus enhance the sensitivity and specificity of the diagnosis of effusion cytology. Hence, CB and IHC have advanced utility over cytological smears in effusion fluid cytological diagnosis.
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BACKGROUND: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of tumors with varying biological, functional, and clinical characteristics that develop from the gastroenteropancreatic tract's diffuse neuroendocrine system. The objective of this study is to determine the clinicopathological features of GEP-NETs at our facility. METHODOLOGY: A cross-sectional analysis of 87 biopsies and resection specimens from January 2020 to January 2022 was performed. The histopathological reports as well as patient's demographic and clinic pathological data were obtained. Two pathologists with a special interest in gastroenteropancreatic pathology blindly reviewed all cases. The tumor grade and stage were determined using the WHO classification (2019) and the AJCC TNM system (8th edition). The data were analyzed with SPSS version 22 (IBM Corp., Armonk, NY, USA). RESULTS: Of the total 87 patients, 49 (56.3%) were male. The age range was 11 to 80 years, with a mean of 45.7±16.4 and the majority (56.3%) were under 50 years. The most frequent symptom was abdominal pain (55.2%). The most common site of GEP-NETs was the appendix (21.8%), followed by the ileum (18.4%), with the majority of tumors being non-functional (96.5%). Furthermore, neuroendocrine tumor (NET) grade 1 accounts for 62% of the total, followed by NET grade 2 (24.1%), neuroendocrine carcinoma (NET) grade 3 (10.3%), and mixed neuroendocrine-non-neuroendocrine neoplasms (MINENs) (3.5%). Synaptophysin was found to be positive in 83.9% cases while Chromogranin A was positive in 39.1%. A pathologic tumor (pT) stage was determined in 47 resection specimens in our study and the most common stage was pT3 (36.1%). Nodal metastasis was found in 25.5% of patients. CONCLUSIONS: According to our study, appendix and ileum were the most common GEP-NETs sites. The tumor site and grade were shown to significantly correlate among the clinicopathological features but there was no discernible correlation between the tumor grade and the gender, age, or pathological tumor (pT) stage.