Background: Serous effusion cytology (SEC) reporting is important for the management of the cancer patient. The International System for Reporting Serous Fluid Cytology (ISRSFC) provides tiered reporting terminology to standardize practice, looking into the risk of malignancy (MAL) for each category. In this study, we have assessed the utility of the ISRSFC and reported our experience at a tertiary cancer center. Materials and Methods: Serous fluid cytology reported from January 2019 to December 2020 was categorized according to ISRSFC diagnostic categories: nondiagnostic (ND), negative for MAL (NFM), atypia of undetermined significance (AUS), suspicious for MAL (SFM), and MAL. The risk of MAL (ROM) and performance parameters were calculated. Results: A total of 2150 serous effusions including 1160 pleural, 929 peritoneal, and 61 pericardial effusions from 2071 patients were reported. There were 742 males and 1329 females. The patient’s age ranged from less than 1 yr to 95 years. The volume of the sample ranged from 0.5 ml to 2000 ml. There were 114 ND (5.32%), 1068 NFM (49.67%), 144 AUS (6.69%), 82 SFM (3.81%), and 742 MAL (34.51%) cases. Adenocarcinoma was the most common MAL involving serous fluids (91.50%). The calculated ROM was 15.38% for ND, 24.26% for NFM, 62.96% for AUS, 79.16% for SFM, and 100% for MAL. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were, respectively, 68.04%, 96.96%, 96.35%, 72.07%, and 81.33%. Conclusion: ISRSFC provides consistent reporting terminology and the ROM for each category aids in clinical correlation and management.

Background Rhabdoid tumors are rare, highly lethal neoplasms characterized by alterations of SMARCB1 gene in chromosome 22, which occurs in infants and children. Fine needle aspiration (FNA) is an effective technique to diagnose this tumor when combined with Immunohistochemistry (IHC) and molecular genetics. In this study, we describe four cases of renal and extra‐renal rhabdoid tumor of which three cases were diagnosed on FNA with IHC. Materials and methods The study includes four children with renal and extrarenal rhabdoid tumor retrieved from cytology archives. FNA was done with cell block, IHC, and cytogenetics. The cytomorphology with ancillary studies were reviewed along with histopathology which was available in 3 out of 4 cases. Results All the four cases had similar cytomorphologic features comprising of large cells having vesicular nuclei which can be central or eccentric with prominent nucleoli and abundant pale cytoplasm. Few cells had intracytoplasmic hyaline inclusion. Cell block with IHC confirmed the diagnosis in three cases. One case in which cell block could not be made the diagnosis was confirmed on biopsy with IHC. Conclusion Rhabdoid tumors are uncommon but aggressive neoplasms with poor prognosis. Our study highlights that they can be diagnosed accurately on FNA cytomorphology when combined with IHC on cell block.

Immunohistochemistry plays a vital role in the diagnosis of small round cell tumors. CD99 immunonegativity is one of the features, which helps in distinguishing neuroblastoma from other small round cell tumors. NKX2.2 is a specific marker of Ewing sarcoma, which is a differential for poorly differentiated neuroblastoma. Here, we present a case of metastatic neuroblastoma showing immunoreactivity for both CD99 and NKX2.2 on cytology of the metastatic site causing diagnostic dilemma. Biopsy study of the adrenal lesion revealed presence of differentiating cells and neuropil, highlighting the importance of evaluation of the primary site and limitation of cytology.

Background: Pleural fluid cytology is a useful diagnostic test to detect metastasis to pleura. Among the metastatic neoplasms to pleural cavity adenocarcinoma is the most common. However there are other neoplasms which rarely infiltrate pleura and produce effusion. The aim of this study is to analyse the spectrum of these unusual malignancies involving pleural fluid with cytomorphology and ancillary studies. Materials and Methods: This is a retrospective study which includes the pleural fluid samples submitted to the cytology section of our institute between 2015 to 2018. A total of 1510 samples are reviewed. Cases with diagnosis other than adenocarcinoma are selected and their cytomorphological details are analysed with ancillary tests wherever available. Results: Out of 1510 samples analysed, 468 are positive for malignancy. Out of 468, 42 cases are uncommon malignancies. These are classified into hematolymphoid (33/42 cases) which includes Nonhodgkin lyphoma, acute lymphoblastic leukemia, chronic myeloid leukemia, multiple myeloma and nonhematolymphoid neoplasms (9 /42) which includes small round cell tumours, squamous cell carcinoma, small cell carcinoma, germ cell tumor and granulosa cell tumour. Conclusion: There are certain uncommonly encountered malignancies in pleural fluid. Cytomorphology plays a key role in diagnosing them with certain cases requiring ancillary studies to confirm the diagnosis.