Reporting Pancreatic FNAC using the Papanicolaou System: Still a Diagnostic Challenge.

Introduction: The Papanicolaou Society of Cytopathology System for reporting Pancreaticobiliary Cytology (PSCPC) is a reliable method to classify pancreatic fine needle aspiration cytology (FNAC) smears. However, it is not without practical problems which can diminish the diagnostic accuracy of the cytological diagnosis. Aims and Objectives: To determine the diagnostic pitfalls while reporting cytomorphology of pancreatic lesions according to PSCPC on correlating FNAC findings with histopathology. Materials and Methods: Retrospective analysis of pancreatic FNAC smears received in the Department of Pathology of our tertiary care institute over a period of 2 years was done. The cytological diagnoses were classified according to the Papanicolaou Society of Cytopathology system of reporting pancreaticobiliary cytology and correlated with histopathology. The reasons of cyto-histological discordance were analyzed. Results: Out of 50 cases in which both FNAC and biopsy of pancreatic lesions were done, 34 cases were positive/malignant (Category VI), eight cases were suspicious for malignancy (Category V), three cases were neoplastic (Category IV), two cases were atypical (Category III), two cases were negative for malignancy (Category II), and one case was non-diagnostic (Category I). Out of 50 cases, histopathology was non-diagnostic due to inadequate material in six cases. The cytological diagnoses were compared with histopathology in the remaining 44 cases. Categories III, IV V, and VI were considered as positive for neoplastic pathology. The sensitivity of FNAC to predict neoplastic pathology was 97.5%, while the specificity was 25%. The positive predictive value was 92.9%. Two cases reported as atypical (Category III) turned out to be adenocarcinoma on histopathology. One case reported as neuroendocrine tumor and two cases reported as adenocarcinoma on cytology displayed features of chronic pancreatitis on histology. One case reported as neoplastic mucinous cyst (Category IV) turned out to be adenocarcinoma on histology (limited concordance). Conclusion: The cytopathologist needs to be wary of the potential pitfalls to improve the diagnostic accuracy of FNACs.

Is mediastinal fine needle aspiration cytology required or redundant? A single institution-based correlation study with core needle biopsy.

INTRODUCTION: Fine Needle Aspiration cytology (FNAC) and core needle biopsy (CNB) are rapid, minimally invasive and useful techniques to evaluate mediastinal lesions. OBJECTIVES: To compare cytopathology with histopathology of mediastinal lesions and analyse reasons for discordance. MATERIAL & METHODS: Retrospective analysis was done in a tertiary care centre in North West India over a period of seven and half years from 1stJuly 2016 to 31st December 2023. Only those patients who had undergone FNAC and trucut biopsy of mediastinal masses were included. The cytopathology and histopathology slides were studied to analyse causes of discordance. Sensitivity, specificity, positive and negative predictive values of FNAC were calculated keeping histopathology as gold standard. RESULTS: Out of 57 cases analysed, eight cases were non diagnostic on cytology. Cytology could effectively classify a lesion as non neoplastic (7) or neoplastic (42). For further subtyping, histopathology and Immunohistochemistry (IHC) were required. Out of 27 cases of cytological - histopathological discordance, 8 cases had sampling error, 15 cases had limited concordance where FNAC could predict possibility of tumor and 4 cases were discordant where subtyping of malignancy varied on CNB. Sensitivity of FNAC to predict definite diagnosis was 90.2 %, specificity was 50 %, positive predictive value of FNAC to give a definite diagnosis was 93.9 %, negative predictive value was 37.5 %. CONCLUSION: Evaluation of mediastinal masses requires combination of cytology, histopathology and ancillary techniques like IHC. FNAC and CNB are complementary modalities and both are essential for rapid, accurate and comprehensive diagnosis.

Contiguous Lumbar Vertebral Involvement with Vertebral Collapse in Giant Cell Tumor: A Usual Tumor with an Unusual Presentation.

Giant cell tumor (GCT) is a primary bone tumor of long bones, which can rarely involve the vertebrae. Contiguous vertebral involvement by GCT is a rare presentation and poses a diagnostic dilemma on imaging. We report a case of GCT involving three contiguous lumbar vertebrae causing vertebral collapse along with a large soft tissue component. Considering the site and clinical presentation, possibilities of a round cell tumor with large extraosseous soft tissue component and malignant neurogenic tumor were suggested on initial radiological examination but histopathology confirmed the diagnosis of GCT. It is important to diagnose this entity correctly because of totally different lines of management. In our case, initial surgical management was excluded in view of high surgical morbidity and, thereby, adjuvant therapy with denosumab was planned.

Spectrum of Adrenal Lesions on Fine-Needle Aspiration Cytology: A Tertiary Care Centre Experience.

Introduction Fine-needle aspiration cytology (FNAC) is an easy, quick, and specialized technique to distinguish neoplastic from non-neoplastic adrenal lesions, yet limited to tertiary care centers. It helps in analyzing symptomatic, as well as incidental adrenal lesions with high sensitivity and specificity. Aim This study was conducted to determine the cytological spectrum of adrenal lesions in a tertiary care center. Material and Methods This was a retrospective study which included a total of 19 cases of adrenal FNAC received from June 2017 till June 2019 in a north Indian tertiary care university hospital. All the lesions were broadly classified into non-neoplastic and neoplastic categories. The non-neoplastic lesions were divided into infective causes and cystic lesions. Neoplastic lesions were further grouped into benign and malignant lesions. Immunohistochemical findings were retrieved from the hospital records wherever accessible. Results A total of 19 cases were aspirated, of which 16 cases (84.20%) yielded satisfactory material. Six cases (31.57%) showed non-neoplastic pathology of which one was a cystic lesion, three were infective (two histoplasmosis and one tuberculosis), and two showed only benign adrenal cortical cells in a setting of known extra-adrenal primary malignancy. The neoplastic group comprised of 10 cases (52.63%) of which 4 cases showed metastatic carcinomatous deposits from a known extra-adrenal primary malignancy and 6 cases showed primary adrenal neoplasm (one case of myelolipoma, one case of pheochromocytoma, and four cases of adrenal neoplasm) which were then subjected to biopsy and immunohistochemistry. A final diagnosis of pheochromocytoma was made in three cases, adrenocortical carcinoma in one case, and one case was inconclusive because of nonrepresentative biopsy. Conclusion Image-guided fine-needle aspiration cytology of adrenal lesions helps to determine the exact nature of the infection, avoids unnecessary surgery, and helps in targeted management. However, histopathological evaluation with immunohistochemistry remains the diagnostic modality of choice with regard to neoplastic lesions.

Peritoneal malignant mesothelioma: Slippery like an eel to diagnose on cytology-case series of 3 cases.

INTRODUCTION: Peritoneal malignant mesothelioma is an extremely rare tumor and is a difficult diagnosis to be made on cytology alone. We report 3 cases where the cytologic features were misdiagnosed as carcinoma/lymphoma but histopathology and immunohistochemistry (IHC) established the diagnosis of malignant mesothelioma. CLINICAL DETAILS: Case 1 was a 60-year-old man with multiloculated ascites and omental caking. Peritoneal fluid was reported as malignant on cytology but was misclassified as adenocarcinoma. Case 2, a 45-year-old man with ascites and peritoneal nodularity, radiologically mimicking peritoneal carcinomatosis, was also reported positive for malignancy on ascitic fluid cytology. Fine-needle aspiration (FNAC) from omental fat revealed signet ring cells, thus misleading to cytologic diagnosis of adenocarcinoma. Case 3 was a 63-year-old man with perisplenic mass with extensive omental caking and peritoneal nodularity that was also suspected to be peritoneal carcinomatosis on radiology. FNAC smears from perisplenic mass showed sheets of plasmacytoid cells. On cytology, the differential diagnoses offered were neuroendocrine tumor or non-Hodgkin lymphoma. The diagnosis of malignant mesothelioma was established only after IHC on histopathologic sections in all these cases. None of our patients had history of prior asbestos exposure. CONCLUSION: In such clinical scenarios, with radiology suggesting peritoneal carcinomatosis, the cytologic features need corroboration by IHC/fluorescence in situ hybridization on cell block or biopsy to correctly identify malignant mesothelioma and differentiate it from metastatic carcinomatous deposits and benign mesothelial proliferation.

Cerebrospinal fluid pleocytosis in immunocompromised patients: Can it be Cryptococcus.

Cryptococcal meningitis commonly affects immunocompromised cases and can have varied presentation. In some instances, the presence of a plethora of inflammatory cells on cerebrospinal fluid (CSF) in an immunosuppressed patient can lead to further investigations, which unravel the presence of cryptococcal meningitis. The aim of this retrospective study was to analyze the spectrum of CSF findings of immunosuppressed patients who were diagnosed to have cryptococcal meningitis. Retrospective analysis of CSF cytospin slides exhibiting pleocytosis and belonging to immunocompromised patients was performed, and these cases were found to have cryptococcal meningitis. Out of 932 cases of CSF (January 2016-July 2017), 10 had pleocytosis and 5 of these 10 cases demonstrated spores of Cryptococcus. Male-to-female ratio was 1:1.5. All the patients were immunocompromised and had CSF leukocytosis. Lymphocytes and monocytes were present in all samples while only one case showed plasma cells. Spores of Cryptococcus were also noted in all the cases and highlighted on India Ink Preparation and Gomori Methenamine Silver stain. All the cases were positive for agglutination-based cryptococcal antigen assay, except one where the test was not done. All immunosuppressed patients having pleocytosis in CSF were found to have cryptococcal infection. Therefore, pleocytosis in CSF in any immunosuppressed patient should raise the suspicion of cryptococcal meningitis. The pathologist and the clinician need to be vigilant in such scenarios to rule out any opportunistic infection and investigate the patient thoroughly for any underlying immunosuppression.

Feasibility of Masood's cytological index for screening breast lesions in low resource setting.

Fine needle aspiration cytology has long been an accepted diagnostic modality in combination with physical examination and mammography to investigate breast lesions. In the present era, more proficient methods such as stereotactic mammographically guided breast biopsy is the preferred choice, however, in low resource setting, FNAC still remains the most cost effective and sampling modality to diagnose breast cancer. With the intention to evaluate the efficacy and limitations of FNAC in evaluation of breast lesions in low resource setting, we employed the Masood's cytological staging system to stratify the breast lesions and correlate them with histopathology wherever possible. All breast lesions aspirates were analyzed and classified according to the Masood's cytological scoring system and correlated with histopathological findings wherever adequate material was available. A total of 776 patients were studied of which 23 aspirates were unsatisfactory, 120 aspirates were categorized as inflammatory breast disease. Six hundred and thirty-three cases were classified according to Masood's cytological system. Nonproliferative breast diseases (Group I) encompassed maximum cases with 55% followed by carcinoma in situ and invasive cancers (Group IV) with 39% and proliferative breast disease without atypia (Group II) and with atypia (Group III) which had equal number of cases constituting 2.4% each. Cyto-histopathological correlation done in 102 cases revealed 100% concordance in group IV and 75% concordance in group III while it could not be performed in Group I and II as no histopathological specimen was available in those patients. Masood Cytological grading for breast aspirates is a reliable and an easily reproducible system which can be used to formulate appropriate treatment protocols in cases presenting with breast lesions.

Pulmonary Hydatid Disease with Aspergillosis - An Unusual Association in an Immunocompetent Host.

Echinococcosis is a common cause of pulmonary cavities. Aspergillus fumigatus, a saprophytic fungus, can colonise pulmonary cavities caused by tuberculosis, sarcoidosis, echinococcosis, bronchiectasis and neoplasms. Infection by Aspergillus is often seen in immunosuppressed cases. However, co-infection of Aspergillus with pulmonary echinococcosis is unexpected and very unusual, especially in an immunocompetent patient. We present the case of a 45-year-old immunocompetent male who came with non-resolving pneumonia and fever for 8 months and dyspnoea since 15 days accompanied by recurrent episodes of hemoptysis since 5 days. Chest X Ray and Computed Tomography scan showed a cystic lesion in the middle lobe of the right lung. Middle lobectomy with video-assisted thoracoscopic surgery was performed and histopathology revealed ectocyst of Hydatid cyst which was also colonised by septate fungal hyphae exhibiting acute angled branching, morphologically consistent with Aspergillus. Gomori Methanamine Silver and Periodic Acid Schiff stains highlighted the hyphae of Aspergillus as well as the lamellated membranes of ectocyst and an occasional scolex of Echinococcus. Sections from surrounding lung parenchyma also showed these fungal hyphae within an occasional dilated bronchus. Thus a diagnosis of dual infection of Aspergillosis and Pulmonary Echinococcosis was established. The possibility of dual infection by a saprophytic fungus must be kept in mind while dealing with a case of a cavitary lesion in long-standing and non-resolving pneumonia, even in an immunocompetent patient. Establishing the correct diagnosis of Aspergillosis with Echinococcosis is essential for proper and complete management.

Hepatic fine-needle aspiration cytology: The role of rapid on-site evaluation in the assessment of hepatic lesions.

BACKGROUND/AIMS: Radiologically guided fine-needle aspiration cytology (FNAC) of internal organs is not cost-effective. Rapid on-site evaluation (ROSE) of smears by a cytopathologist can improve the diagnostic yield of FNACs and save time and money by reducing the need for repeat procedure/biopsy. To determine the role of ROSE in the diagnostic outcome of hepatic lesions by comparative analysis of FNAC with and without ROSE by a cytopathologist. MATERIALS AND METHODS: Hepatic FNACs were retrospectively analyzed over two separate time periods from January 2011 to June 2013 and from January 2015 to July 2016. Smears from 2015-2016 were subjected to ROSE by a cytopathologist after staining with toluidine blue for 1 min to assess adequacy of the material. Final report was given after hematoxylin and eosin, May Grünwald Giemsa, and Papanicolaou staining were performed. Chi-square test (non-parametric) was used to determine if there was a statistically significant increase in the diagnostic yield with ROSE. RESULTS: During 2011-2013, of the 160 radiologically guided FNACs for hepatic lesions, 22 were non-diagnostic, whereas during 2015-2016, of 142 radiologically guided hepatic FNACs, only six were non-diagnostic. With the application of ROSE, there was a statistically significant increase in the diagnostic yield of hepatic FNACs from 86.25% to 95.8% (p=0.015). CONCLUSION: ROSE performed by a cytopathologist using toluidine blue can increase the diagnostic yield of hepatic FNACs and reduce the cost of healthcare by eliminating the need for a repeat procedure.

Coinfection of Sarcina ventriculi and Candida in a patient of gastric outlet obstruction: An overloaded pyloric antrum.

Sarcina ventriculi is a rare gram-positive, anaerobic bacteria, associated with delayed gastric emptying. We report a case of a 45-year-old lady, who presented with features of gastric outlet obstruction, and coinfection of S. ventriculi and Candida was detected on examining gastric brushings and biopsy. S. ventriculi is identified by its peculiar configuration in the form of tetrads and octets. Coexistence of S. ventriculi with other organisms is highly unusual.

Beware of Bone Marrow: Incidental Detection and Primary Diagnosis of Solid Tumours in Bone Marrow Aspiration and Biopsies; A Study of 22 Cases.

BACKGROUND & OBJECTIVE: Introduction: First detection of any solid tumour as metastatic deposits in bone marrow directs clinicians to start searching for the primary tumour. Detection of bone marrow metastasis determines the stage of the malignancy, prognosis, mode of treatment, chemotherapeutic response and follow-up in case of relapse. The aim of the current study was to analyse the clinico-haematological presentation and morphological pattern of infiltration of solid tumours detected first as metastatic deposits on bone marrow examination. METHODS: Three-year retrospective analysis of MGG-stained bone marrow aspiration smears and touch imprints of the bone marrow biopsy and Hematoxylin and Eosin (H&E) stained histopathological sections of biopsies was performed at the Department of Pathology at a tertiary care institute (January 2014 to December 2016). The morphological pattern of metastatic deposits and haematological profiles of the patients were analysed. Exclusion criterion was the presence of hematolymphoid malignancies. RESULTS: In 22 cases, bone marrow was the first site of detection of metastasis. The age of the patients ranged from 3 years and 10 months to 82 years, with equal gender predilection. Overall, 16 cases had cytopenias, 9 cases each had leucocytosis and leukoerythroblastic presentation. The metastasis was from Ewing's sarcoma, prostate carcinoma, gastric adenocarcinoma invasive duct carcinoma breast, gallbladder carcinoma, lacrimal duct carcinoma and invasive papillary urothelial carcinoma. CONCLUSIONS: Bone marrow examination is a cheap and reliable investigation to detect metastasis in an unsuspecting case. Bilateral trephine biopsies are recommended to increase the efficacy of detecting bone marrow metastasis.

Entamoeba histolytica: A surprising coexistence with adenocarcinoma - Never brush aside brushings for biopsy.

Entamoeba histolytica has been rarely reported as superadded infection over carcinomatous growth on rectal brushings. We present a case of 68-year-old male who presented with abdominal pain and bleeding per rectum who was found to have an ulceroproliferative growth on sigmoidoscopy. Rectal brushings revealed coexistence of E. histolytica with malignant cells of adenocarcinoma. No organism was detected on biopsy of the tumor, which also showed adenocarcinoma, because of possible surface colonization of the tumor by Entamoeba. This case highlights the role of rectal brushings in detecting superadded infection in a case where both brushings and biopsy were performed. It is always important to report infection superadded on malignancies for optimum management of the patients.

Role of FNA and Special Stains in Rapid Cytopathological Diagnosis of Pulmonary Nocardiosis.

BACKGROUND: Nocardia, a gram-positive aerobic bacillus of the Actinomycetales family, is a significant opportunistic pathogen in immunocompromised individuals. Clinical and radiological features of pulmonary nocardiosis are nonspecific and can be misdiagnosed as tuberculosis, pneumocystis, staphylococcal or fungal infections, or as malignancy. Aspiration cytology with special stains is a quick and effective approach for accurate diagnosis. MATERIALS AND METHODS: We present 7 cases of pulmonary nocardiosis, admitted to the pathology department in a tertiary-care hospital in Punjab. Clinical findings, immune status, laboratory tests, chest radiographs, and computed tomography scans were reviewed. Cytologically, special stains like 1% Ziehl-Neelsen (ZN), 20% ZN, periodic acid-Schiff (PAS), Grocott methenamine silver (GMS), and reticulin stains were studied along with May-Grünwald Giemsa, Papanicolaou, and hematoxylin and eosin. RESULTS: All the patients were immunocompromised. The radiological changes were nonspecific. Cytomorphology showed acute and chronic inflammatory infiltrates with necrosis. None of the cases showed well-defined granulomas. GMS, modified 1% ZN and, Gordon and Sweet reticulin stains highlighted the delicate filamentous bacteria in all cases. PAS and 20% ZN stain for tuberculous bacilli were uniformly negative. CONCLUSION: FNAC can provide a quick and accurate diagnosis of nocardiosis and thereby facilitate timely medical management.

Impact of SurePath® liquid-based preparation in cytological analysis of peritoneal washing in practice of gynecologic oncology.

CONTEXT: Peritoneal washing is performed for staging of gynecologic tumors to detect subclinical intraperitoneal metastases. AIM: The aim of the present study was to assess the impact of SurePath™ liquid-based cytology (LBC) in peritoneal washing in various gynecological malignancies. SETTINGS AND DESIGN: An audit of peritoneal-fluid/washing (January 2012 to July 2013) was performed with corresponding gynecologic specimens. All peritoneal washings were processed using both conventional and LBC technique. Suspicious cases on cytology were reported along with gynecologic specimens. RESULTS: There were a total of 393 peritoneal fluids. Eighty-three (21.1%) were positive for malignancy, and the corresponding histology was available in 352 (89.6%) cases. Sixty-nine positive samples had ovarian malignancies and 5 had uterine causes. There were 9 cases of peritoneal washings in which no histopathology was available. The most common cause of positive peritoneal cytology was ovarian serous carcinoma in 55/84 (65.5%) cases. Other causes included mucinous cystadenocarcinoma, dysgerminoma, squamous cell carcinoma in teratoma, yolk sac tumor, and granulosa cell tumor. Uterine causes included 2/45 (4.4%) cases of endometrioid adenocarcinoma, » (25%) cases of clear cell carcinoma, ½ (50%) cases of carcinosarcoma, and » (25%) cervix carcinoma. On review of positive cases (n = 83), 10 cases were identified, which had nil (n = 4) to low cellularity (<3 tumor clusters/smear; n = 6) on conventional smears, and were confirmed malignant on LBC. CONCLUSIONS: The most common ovarian malignancy causing positive peritoneal cytology is papillary serous carcinoma. Endometrioid adenocarcinoma rarely leads to positive peritoneal cytology. LBC technique leads to concentration of tumor cells causing reduction in false negative cases, especially in hemorrhagic and low-cellular cases.

Parotid or carotid? Misled by site.

We present an interesting scenario where a 64 years old male presented with a long standing painless, infra-auricular swelling, which had progressively increased in size. Based on the site, the clinical impression was of a salivary gland lesion and FNAC was performed. The smears were unusually cellular and had necrotic background. The cytological diagnosis was a cystic neoplasm of salivary gland, possibly mucoepidermoid carcinoma. Warthin's tumor was also kept in differential. However, the radiological investigations, which were made available after the FNAC report were conflicting with cytological diagnosis of a malignancy and were characteristic of a carotid body tumor, generally a benign neoplasm. Surgical excision of the tumor with regional lymph node sampling was done and histopathological examination solved the puzzle by revealing metastasis of paraganglioma to right posterior triangle lymph nodes. This case is unique because of the unusual presentation of a malignant paraganglioma as an infra-auricular swelling, which was clinically considered as a parotid tumor. The clinician as well as the pathologist need to be aware of such diagnostic pitfall. Diagn. Cytopathol. 2017;45:569-573. © 2017 Wiley Periodicals, Inc.

Nodular Cystic Basal Cell Carcinoma of the Trunk: a Diagnostic Dilemma in an Unsuspecting Youth.

Basal cell carcinoma (BCC) commonly affects the elderly and is mostly confined to the head and neck region. Only 10% of all cases occur on the trunk. We presented a case of bullous lesion on the abdomen in a young male, initially diagnosed by clinicians as a vascular nevus. Histopathological examination and immunohistochemistry (IHC) revealed it to be Nodular cystic variant of BCC. This rare variant of BCC morphologically resembles benign skin adnexal tumor of Eccrine syringofibroadenoma. Ber Ep4 positivity on IHC established the correct diagnosis. This case highlights that nodular cystic variant of BCC can be a diagnostic dilemma for clinicians and pathologists.

Cytohistological discordance on gastrointestinal brushings: Facts unfolded.

INTRODUCTION: Brush cytology is a rapid, cost-effective, and reliable tool to diagnose gastrointestinal tract (GIT) lesions in low-resource settings. Most of the studies on GIT brushings have focused on upper GI lesions. We have studied the diagnostic accuracy of brush cytology in the entire length of GIT and correlated the cytological diagnosis with histopathology. The aim of this study is to study diagnostic utility of brush cytology of GIT lesions in the context of correlation with biopsy and study the factors responsible for cytohistological discordance. MATERIALS AND METHODS: A retrospective analysis of 101 cases of prebiopsy brush cytology samples of GIT lesions was done over a period of 1 year (June 2014 to May 2015). The cytological diagnosis was compared with histopathological diagnosis and percentage of correlation was calculated. The reasons for discordance were noted and studied. RESULTS: The cytological diagnosis of 79 (78.2%) correlated with histopathological diagnosis. There was discordance in cytological and histological diagnosis in 22 cases (21.8%). Inadequacy of cytological sample and overlap of nuclear atypia caused by regenerative changes and malignancy were significant factors for cytohistological discordance. CONCLUSION: The diagnostic accuracy of brush cytology can be improved by taking appropriate measures to eliminate factors responsible for fallacies in cytological diagnosis.

Disseminated Histoplasmosis: A Fatal Opportunistic Infection in Disguise.

Histoplasma capsulatum is no longer confined to certain geographic areas and should always be considered in the differential diagnosis of lymphadenopathy and organomegaly in HIV-positive patients. We present an unusual case of a 20-year-old immunocompromised male of African origin presenting with fever, jaundice, hepatosplenomegaly, and retroperitoneal and cervical lymphadenopathy. Fine needle aspiration (FNA) smears from the cervical lymph node revealed numerous yeast forms of histoplasma in macrophages. The patient succumbed to the fulminant infection. Postmortem liver biopsy also revealed infiltration by histoplasma, confirming the diagnosis of disseminated histoplasmosis. This case highlights the variable nature of the clinical presentation of disseminated histoplasmosis which can mimic tuberculosis, leishmaniasis, or lymphoma. FNA cytology is a rapid, cost-effective, and reliable diagnostic tool for early detection and prompt management of histoplasmosis.

Myeloid Sarcoma: An Unusual Case of Mediastinal Mass and Malignant Pleural Effusion with Review of Literature.

Myeloid sarcoma is an extramedullary tumor seen most commonly in patients with acute myeloid leukemia and less frequently in chronic myeloid leukemia, myelodysplastic syndrome and rarely, in an isolated form without any other underlying malignancy. Malignant pleural effusion in hematological malignancies is rare when compared with solid tumors. We present an unusual case of myeloid sarcoma in which a mediastinal mass with pleural effusion was the initial presentation. A 27 year old gentleman presented with complaints of fever, chest pain and swelling in the anterior chest wall for 6 months. Examination revealed a lump measuring 5 × 5 cm on the left side of the chest wall. Hematological evaluation showed hemoglobin-14.2 g/dL, platelet count-233 × 10(9)/L, TLC-117 × 10(6)/L with normal differential counts. Contrast enhanced computerised tomography (CECT) confirmed the presence of a soft tissue mass in the superior mediastinum abutting against the chest wall. Core biopsy was suggestive of myeloid sarcoma and immunohistochemistry was positive for myeloperoxidase and negative for CD3, CD 20 and CD 23. Pleural fluid analysis showed the presence of malignant cells. Bone marrow examination did not show an excess of blasts. A final diagnosis of extramedullary myeloid sarcoma with malignant pleural effusion was made. The patient was given induction chemotherapy (3 + 7 regimen) with daunorubicin and cytosine arabinoside. Repeat CECT done on day 28 showed complete resolution of pleural effusion and significant reduction in the size of mediastinal mass. The patient has successfully completed three cycles of consolidation therapy following which there has been complete resolution of the mass. He remains asymptomatic on close follow up.