Pleural mass forming extramedullary hematopoiesis masquerading as a malignant neoplasm

Extramedullary hematopoiesis (EMH) represents the presence of immature hematopoietic elements and their differentiation into mature blood components outside of the medullary bone and may be seen in a variety of circumstances in the postnatal period, but is most strongly associated with disorders of the hematopoietic system. Postnatally, EMH is typically identified at sites of fetal hematopoiesis, the spleen, and liver, but occasional reports have identified it in nearly every tissue of the body. We report a case of EMH presenting as pleural mass, initially suspected to represent a neoplastic process in a patient with multiple comorbidities, including history of carcinoma, but without co‐existing hematologic disorder. On‐site evaluation of the fine‐needle aspiration specimen was initially suspicious for a malignant neoplasm, but further evaluation revealed the lesion to be a mass forming focus of non‐hepatosplenic EMH. In the era of increasing utilization of imaging, mass forming EMH is increasingly detected. When unsuspected, EMH may present a diagnostic challenge for the pathologist and may be confused for a neoplastic process. Diagn. Cytopathol. 2015;43:996–999. © 2015 Wiley Periodicals, Inc.     

37-year-old woman with multiple intracranial masses

Extramedullary hematopoiesis (EMH), defined as the presence of hematopoiesis outside bone marrow and peripheral blood, occurs asa compensatory phenomenon in several hematologic disorders and bone marrow dysfunction. EMH predominantly affects reticuloendothelial system including the spleen, liver and lymph nodes. Here,we report a rare case of multiple intracranial meningeal EMH. A37-year-old woman was anemic with gradually worsening vision for 8 months. Multiple extra-axial masses were found on imaging and the patient underwent the biopsy for the left frontotemporal lesion.Final diagnosis was multiple intracranial meningeal EMH. Treatment of fractionated external beam radiotherapy resulted in marked symptomatic improvement. This case indicates that although the diagnosis of meningeal EMH is difficult, there is a need to consider EMHin the differential diagnosis of anemic patients with tumor-like mass lesions in extramedullary sites.     

Endoscopic ultrasonography‐guided fine‐needle aspiration for diagnosing upper gastrointestinal submucosal lesions: A prospective study of 50 cases

The objective was to assess EUS‐FNA for diagnosing intramural upper GI tract lesions. The subjects were 50 patients (21M/29F) with upper GI submucosal lesions who underwent EUS‐FNA at a referral center for GI system over a 12‐month period. All cases were followed for 1 year after initial EUS‐FNA. Cytologic diagnoses were categorized as benign, malignant, suspicious for malignancy, mesenchymal tumor, endocrine tumor, or nondiagnostic. All tumors were assessed for various cytomorphologic features. The accuracy of the initial FNA diagnoses was evaluated for each patient who also underwent subsequent histopathological examination of a core biopsy and/or surgical biopsy/resection material of the same lesion. According to the site of the lesions; while 84% of all esophageal lesions were diagnosed as mesenchymal; 67% of all gastric lesions were mesenchymal. The sole lesion was nonmesenchymal (benign cyst) in duodenum. The sensitivity, specificity, positive and negative predictive values, and accuracy of EUS‐FNA for diagnosing submucosal mesenchymal tumors of the upper GI tract were 82.9, 73.3, 87.9, 64.7, and 80%, respectively. The corresponding values for nonmesenchymal lesions were 100, 85.7, 80, 100, and 90.9%. Our experience confirms that EUS‐FNA is an extremely valuable tool for diagnosing submucosal lesions of the upper GI, and is particularly useful in cases where endoscopic forceps biopsy does not lead to diagnosis. Optimal results can be yielded by a close working relationship between the gastroenterologist and pathologist. Diagn. Cytopathol. 2011. © 2010 Wiley‐Liss, Inc.     

Primary pancreatic diffuse large B‐cell lymphoma diagnosed by endoscopic ultrasound guided FNAC: A rare entity

Primary pancreatic lymphoma (PPL) is an uncommon neoplasm which can clinico‐radiologically mimic carcinoma. But the management of these patients differs from that of a carcinoma. Endoscopic ultrasound (EUS) guided fine‐needle aspiration (FNA) serves as a potential tool to identify pancreatic lymphomas and thus prevent an invasive diagnostic test. This case report describes the presentation and diagnosis of primary pancreatic lymphoma. A 37‐year‐old female presented with nausea, vomiting with signs of icterus and elevated liver function test and Bilirubin. Abdominal computed tomography (CT) revealed a hypodense lesion in the head of the pancreas. EUS guided FNA was performed and cytological material was collected. The lesion was diagnosed as Non‐Hodgkin Lymphoma (NHL) and subtyped as diffuse large B‐cell lymphoma‐germinal centre (DLBCL‐GCB) base on immunohistochemistry on cell block. The patient was started on rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (RCHOP) regimen. EUS guided FNA along with ROSE, cell bock, and immunocytochemistry helps in the diagnosis of primary pancreatic lymphoma.     

Primary pancreatic leiomyosarcoma with metastasis to the liver diagnosed by endoscopic ultrasound‐guided fine needle aspiration and fine needle biopsy

Primary pancreatic leiomyosarcomas are rare tumors of the pancreas that are usually diagnosed after resection or by biopsy. One case in the literature has utilized endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) cytology. We report a second case of a primary pancreatic leiomyosarcoma that yielded diagnostic material on EUS‐FNA cytology. A 72‐year‐old female presented with 3–4 months of abdominal pain. A CT scan showed a large heterogeneous, lobulated pancreatic head and uncinate mass and multiple hypoattenuating liver lesions. An EUS‐FNA was performed on one of the liver lesions with a 25‐gauge needle, yielding an adequate sample with lesional cells. The initial read was a spindle cell neoplasm. A subsequent endoscopic ultrasound‐guided fine needle biopsy with a 22‐gauge needle was performed on the pancreatic head mass to rule out two primaries and to provide tissue for a mitotic index in the case of gastrointestinal tumor. Both the cell block of the EUS‐FNA and the core biopsy were equally cellular and showed interlacing spindle cells that stained positive for SMA and negative for DOG‐1, CD 117, and CD34. In addition, the core biopsy of the pancreas stained positive for Desmin. A diagnosis of a primary pancreatic leiomyosarcoma was made and the patient was started on systemic chemotherapy. Primary pancreatic leiomyosarcomas are rare pancreatic tumors that may yield diagnostic material by EUS‐FNA with a 25‐gauge needle. Diagn. Cytopathol. 2016;44:1070–1073. © 2016 Wiley Periodicals, Inc.     

Nodular hematopoiesis of the liver diagnosed by fine-needle aspiration cytology

A case of tumor-like extramedullary hematopoiesis (EMH) of the liver diagnosed by fine-needle aspiration cytology guided by computer tomography (CT) is reported. The initial clinical diagnosis was metastatic carcinoma from an adrenal gland primary. Five other cases of tumor-like EMH diagnosed by FNA have been presented in the literature. In two of the cases, the primary clinical diagnosis was metastatic tumor. The most common location for tumor-like EMH is paravertebral and intrathoracic. Three such cases of paravertebral tumor-like EMH have been diagnosed by FNA. Nodular EMH can be found rarely in other organs as in the liver. Diagn. Cytopathol. 16:51–54, 1997. © 1997 Wiley-Liss, Inc.     

Extramedullary multiple myeloma involving the liver and periportal lymph node,diagnosed by EUS‐FNA in a patient with cirrhosis

Extramedullary multiple myeloma (EMM) involving the liver as a focal space‐occupying lesion is very rare, especially in the patients with cirrhosis. Here, we report a case of EMM in the liver and periportal lymph node, diagnosed by endoscopic ultrasound guided‐fine‐needle aspiration (EUS‐FNA). A 57‐year‐old male patient, with history of cirrhosis, presented with abdominal pain and pancytopenia. The abdominal magnetic resonance imaging (MRI) demonstrated a 6.5 cm left hepatic mass with a 1.1 cm malignant‐appearing periportal lymph node and diffuse osseous lesions. The cytology specimens from the hepatic mass and the periportal lymph node were obtained through EUS‐FNA without rapid on‐site evaluation (ROSE). The thin‐layer preparations (ThinPrep) showed abundant plasmacytoid cells, which were confirmed to be Kappa‐restricted neoplastic plasma cells by the cell block preparations. Later, his serum level of Kappa light chain was found significantly elevated by flow cytometry, which was identified as monoclonal IgA Kappa light chain by serum protein electrophoresis (SPEP) with immunofixation. The patient was diagnosed as IgA multiple myeloma with extramedullary involvement of the liver and periportal lymph node. This is the first case showing the ThinPrep cytomorphologic features of EMM in the liver and periportal lymph node. This case highlights the importance of distinguishing plasma cells from being hepatocytes and lymphocytes on the ThinPrep and also emphasizes the utility of the cell block in the diagnosis of plasma cell neoplasm.     

Utility of endoscopic ultrasound‐guided fine‐needle aspiration in the diagnosis and staging of colorectal carcinoma

The objective of this study is to assess the utility of endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) in the diagnosis and staging of colorectal cancer. The study includes patients who underwent EUS‐FNA at our institution for staging of colorectal carcinoma or for evaluation peri‐rectal masses or distal metastases from August 2000 to November 2010. We assessed the frequency with which EUS‐FNA procedure confirms the diagnosis of malignancy and the percent of cases in which it modifies staging of colorectal carcinoma. Using histology as a reference standard, we also assessed the diagnostic performance. We identified 79 cases of EUS‐FNA from 77 patients, mean (SD) age of 60 (12.5), 44 males. Twenty‐seven (34%) aspirates were from patients with primary rectal/peri‐rectal masses, 15 (19%) were from patients with suspected regional lymph node metastasis, and 37 (47%) were cases of suspected of distal metastasis. All lesions were clinically suspicious for primary or metastatic colorectal carcinoma. On cytologic examinations, 43 (54%) cases were confirmed as malignant, 6 (8%) were benign neoplasms, 4 (5%) were suspicious for malignant neoplasm, 2 (3%) showed atypical cells, and the rest 24 (30%) were negative for neoplasms. Fourteen of 27 (52%) of the local rectal masses were confirmed as colorectal carcinoma. Eleven of 15 (73%) regional lymph nodes were positive for metastasis—all, but two of these metastases, were of colorectal origin. Twenty of 37(54%) distal lesions were metastatic neoplasms and 15 of those were colorectal in origin. Diagnosis of primary colorectal carcinoma was confirmed in 52% of the clinically suspicious primary lesions and in 42% regional or distal metastatic lesions. Using histology as a reference standard in 27 of 79 (29%) cases, we calculated an overall sensitivity, specificity, and positive and negative predictive values (C.I) of EUS‐FNA of 89% (74–100%), 79% (50–100%) 89% (74–100%), and 79% (51–100%). EUS‐FNA is useful for assessing primary and metastatic colorectal lesion. This technique improves staging of suspected nodal or distant metastases. Diagn. Cytopathol. 2013;41:1031–1037. © 2011 Wiley Periodicals, Inc.     

Mediastinal ganglioneuroma diagnosed by transesophageal endoscopic ultrasound guided fine needle aspiration (EUS‐FNA)

Ganglioneuromas are rare benign tumors that arise from the sympathetic nerve fibers and represent the final maturation stage of neuroblast tumors. The most common sites of involvement in the body include posterior mediastinum, followed by retroperitoneum, adrenal gland, and soft tissues of the head and neck. In the mediastinum, this tumor is most frequently located in posterior compartment, together with other neurogenic tumors. The reports of mediastinal ganglioneuroma diagnosed by fine needle aspiration (FNA), especially endoscopic ultrasound‐guided FNA (EUS‐FNA) are very sparse. We describe the clinical, radiologic, cytologic, gross and histologic features of mediastinal ganglioneuroma diagnosed by transesophageal endoscopic ultrasound‐guided fine needle aspiration.     

Large platelet aggregates in endoscopic ultrasound‐guided fine‐needle aspiration of the pancreas and peripancreatic region: A clue for the diagnosis of intrapancreatic or accessory spleen

Intrapancreatic and intraabdominal accessory spleens (IPIASs) are rarely encountered in endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) biopsies. However, as incidentally discovered IPIAS can mimic a benign or malignant pancreatic neoplasm on imaging studies, a definitive diagnosis made by EUS‐FNA can avert an unnecessary surgical intervention or additional radiologic follow‐up. We report five cases of intrapancreatic splenules and one case of accessory spleen (AS) in which a definitive diagnosis was made on EUS‐FNA. Previously recognized FNA cytomorphologic features of splenic tissue, including ASs and splenosis, are endothelial cells and polymorphous lymphocytes admixed with neutrophils, eosinophils, plasma cells, histiocytes, and lymphoglandular bodies. We describe the additional finding of abundant large platelet aggregates as another distinguishing feature of splenic tissue on FNA. In all six cases, large platelet aggregates were identified along with polymorphous lymphoid cells, lymphoglandular bodies, loose aggregates of endothelial cells and scattered or aggregated bland spindle cells. A review of 10 consecutive cases of EUS‐FNA‐sampled benign intraabdominal lymph nodes showed that the presence of large platelet aggregates, three‐dimensional aggregates of lymphoid cells and of bland slender spindle cells and the absence of follicular germinal cell components (tingible body macrophages and lymphohistiocytic aggregates) are useful in differentiating IPIASs from reactive lymph nodes. Immunoperoxidase stains were useful to confirm a suspected IPIASs by showing CD31‐positive acellular flocculent material, consistent with large platelet aggregates and a rich CD8‐positive endothelial cell network between CD45‐positive lymphoid cells and CD68‐positive histiocytes in all six cases. Diagn. Cytopathol. 2013;41:661–672. © 2013 Wiley Periodicals, Inc.     

Cytopathologist‐performed ultrasound‐guided fine‐needle aspiration of parathyroid lesions

The gold standard to determine the cause of primary hyperparathyroidism (PHPT) is bilateral neck exploration. As most cases are caused by parathyroid adenoma, there is a movement toward preoperative localization of the abnormal gland by ultrasound and/or Tc⁹⁹‐sestamibi scan and minimally invasive parathyroidectomy. Nonpalpable thyroid nodules are common and cannot be differentiated from parathyroid lesions by imaging alone. This study examines cytopathologist‐performed ultrasound‐guided fine‐needle aspiration (UG‐FNA) in diagnosis of parathyroid lesions. Between January 1, 2007 and December 31, 2008, seven patients with PHPT or other parathyroid lesions with one or more sonographically‐visible thyroid masses underwent cytopathologist‐performed UG‐FNA with immediate cytological evaluation (ICE). One mass was palpable and nine were nonpalpable. Three parathyroid adenomas, two benign colloid nodules, one papillary carcinoma, three parathyroid cysts, and one thyroid cyst were diagnosed. The nodules in three patients with parathyroid adenomas were identified as follicular lesion/neoplasm on ICE. Additional UG‐FNA passes were made to obtain tissue for immunohistochemistry stains, which confirmed parathyroid origin. Two of these patients had a separate benign colloid nodule and one had a thyroid cyst diagnosed by UG‐FNA. The PHPT patient with papillary carcinoma on UG‐FNA had the malignancy confirmed at surgery and a sonographically occult parathyroid adenoma. The three patients with thyroid cysts identified by radiology were suspected of being parathyroid cysts on the basis of real‐time sonographic features at the biopsy table. The clear cyst fluid obtained by UG‐FNA had markedly elevated PTH. Cytopathologist‐performed UG‐FNA can distinguish between parathyroid and thyroid nodules in patients with suspected parathyroid lesions. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.     

Metastatic pheochromocytoma to the pancreas diagnosed by endoscopic ultrasound‐guided fine needle aspiration: A case report and review of literature

Pancreatic pheochromocytomas are rare and typically diagnosed by local resection. We present the first reported case of metastatic pheochromocytoma to the pancreas diagnosed by endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) and cytology. A 67‐year‐old female presented with 2 to 3 months of abdominal pain. A CT scan showed a large mass in the head of the pancreas engulfing the superior mesentery artery and vein, along with a large mass in the left adrenal gland. An EUS‐FNA was performed on the pancreatic mass with a 22‐gauge needle, yielding an adequate sample. Papanicolaou stain, Diff‐Quik, and cell block showed loosely cohesive clustered tumor cells and singly dispersed pleomorphic naked tumor nuclei with anisonucleosis and cytoplasmic vacuolization. Tumor cells stained positive for synaptophysin, chromogranin A, and CD56 and negative for CK AE1/3 and CK AE1/3‐CAM5.2 cytokeratin cocktail. Because of cytokeratin negativity, diffusely positive neuroendocrine markers, and the presence of an adrenal mass, a metastatic malignant pheochromocytoma was suspected. Additional testing showed elevations in plasma metanephrines and normetanephrines, urine metanephrine‐to‐creatinine and normetanephrine‐to‐creatinine ratios, and serum chromogranin A. An iodine¹²³‐metaiodobenzylguanidine (MIBG) scan was obtained, which showed significantly increased MIBG uptake in the left adrenal lesion. A diagnosis of metastatic malignant pheochromocytoma was made. Surgical oncology was consulted, who recommended against resection of the adrenal mass in favor of outpatient management. Metastatic pheochromocytoma to the pancreas are rare tumors that may yield diagnostic material by EUS‐FNA with a 22‐gauge needle.     

Lymphoepithelial cysts of the pancreas: endosonography-guided fine needle aspiration

Lymphoepithelial cyst (LEC) of the pancreas is a rare lesion. Here, we report three cases that we encountered during 2007 in our institution, which were evaluated by endosonography (EUS) and fine needle aspiration (FNA). All three patients were male with ages ranging from 47 to 77 years. Each patient had a single, cystic mass of the body/tail of the pancreas that was found incidentally on CT scan. The size of the masses ranged from 3 to 6.5 cm radiologically. For each patient, EUS showed a well-circumscribed, lobulated mass with smooth contours; the remainder of the pancreas appeared normal without ductal dilation. FNA of all three masses demonstrated predominantly anucleated squamous cells, amorphous keratinous debris, and lymphocytes. Cholesterol crystals were present in one case. One patient underwent surgical resection and the diagnosis of LEC was confirmed histologically. In conclusion, pancreatic LECs are extremely rare, benign cystic lesions. FNA study may help to render a correct diagnosis and reduce unnecessary surgery.     

Fine‐needle aspiration of a presacral myelolipoma: A case presentation with flow cytometry and immunohistochemical studies

Myelolipomas are benign soft‐tissue tumors predominantly found in the adrenal gland. Extra‐adrenal myelolipomas are rare, with about 30 previous cases reported. Approximately half of the reported cases were located in the presacral region. These were usually found at autopsy or during the workup of vague abdominal symptoms. Histologically, these lesions show bone marrow elements, with adipose tissue and scattered lymphoid aggregates. Radiologically‐guided fine‐needle aspiration (FNA) is helpful in establishing the diagnosis, thus obviating resection in some patients. We report on a case of an incidental presacral myelolipoma that underwent examination by computer tomography, magnetic resonance imaging, FNA, and immunohistochemical staining. This lesion was also analyzed by flow cytometry. To our knowledge, the use of the latter technique in the characterization of such tumors has not been previously reported. Diagn. Cytopathol. 1999;20:47–51. © 1999 Wiley‐Liss, Inc.     

Pancreatic fine‐needle aspiration cytology in patients < 35‐years of age: A retrospective review of 174 cases spanning a 17‐year period

Pancreatic lesions in young patients are relatively rare and, to our knowledge, the clinical value of pancreatic fine needle aspiration (FNA) in patients < 35 years of age has not been previously established by any other large retrospective studies. All pancreatic endoscopic ultrasound‐guided FNA (EUS‐FNA) cases performed on patients < 35 years of age were identified for a 17‐year period (1994–2010). All FNAs and all available correlating surgical pathology reports were reviewed. There were a total of 174 cases of pancreatic FNA performed on 109 females and 65 males under the age of 35 (range: 8–34, mean: 27 years). The FNA diagnoses included 37 malignant, 114 negative, nine atypia/suspicious, and 14 cases that were nondiagnostic. Of the 37 malignant FNA cases, the diagnoses included 18 pancreatic neuroendocrine tumors (PanNeT), 11 solid pseudopapillary neoplasms (SPN), five adenocarcinomas and three metastatic neoplasms. Histologic follow‐up was available in 22 of the 37 malignant cases diagnosed by FNA, and the diagnosis was confirmed in 21 cases. One pancreatoblastoma was misclassified as SPN on EUS‐FNA. False negative diagnoses were noted in three cases of low‐grade mucinous cystic neoplasm and one case of PanNeT. The most common type of neoplasms diagnosed by EUS‐FNA in patients < 35‐year old is PanNeT, followed by SPN with both tumors accounting for 75% of all the neoplasms encountered in this age group. The sensitivity and specificity for positive cytology in EUS‐FNA of the pancreas to identify malignancy and mucinous neoplasms were 90% and 100%, respectively. Diagn. Cytopathol. 2014;42:297–301. © 2013 Wiley Periodicals, Inc.     

Increased diagnostic yield of endoscopic ultrasound‐guided fine needle aspirates with flow cytometry and immunohistochemistry

Endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) is the most sensitive and specific test for establishing a tissue diagnosis for many gastrointestinal malignancies; however, cytologic morphology alone may not be definitive for subsets of tumors. Our aim was to quantify the impact of the broad application of flow cytometry (FC) and immunohistochemistry (IHC) on EUS‐FNA diagnostic yield. A retrospective chart review was performed on EUS procedures at a tertiary referral, academic medical center. All EUS‐FNA cases performed over a 21‐month period were examined. Of 606 EUS procedures reviewed during the period of study, 264 utilized FNA. After pancreatic cyst cases were excluded, 235 EUS‐FNA cases for 221 patients were selected for analysis. For cases with subsequent histological evaluation, including the subset utilizing FC/IHC, the sensitivity of EUS‐FNA was 89%, specificity was 100%, and accuracy was 91%. One quarter (58/235, 25%) of the tissue specimens underwent further testing by FC/IHC. There were 48 definitive diagnoses made in the subset utilizing FC/IHC. In 20 of the 48 diagnoses (42%), FC/IHC was deemed critical to the diagnosis, and without FC/IHC testing in those cases, the overall sensitivity and accuracy of EUS‐FNA would be reduced to 74 and 77%, respectively. FC/IHC allowed for six diagnoses rarely or not previously described by EUS‐FNA. Application of FC/IHC improves characterization predominantly for nonadenocarcinoma tumor subtypes and may lead to a diagnostic result for tumors not previously characterized by EUS‐FNA. With an adequate tissue sample, broad application of FC/IHC increases the diagnostic yield of EUS‐FNA. Diagn. Cytopathol. 2013;41:1043–1051. © 2012 Wiley Periodicals, Inc.     

October 2001: 40-year-old Xhosa male with back pain and leg weakness

A 40-year-old Xhosa male presented with progressive upper lumbar back pain and weakness At examination he was emaciated and had enlarged lymph nodes in the groin and axilla. Both lower limbs were severely atrophic and weak. Sensation to touch and pain was decreased below L3 bilaterally. MR of the spine showed a discrete, contrast-enhancing epidural mass. A T10-T12 laminectomy revealed an soft, vascular extradural tumor dorsal to the cord. The mass was loosely applied to the dura and easy to remove. The operative specimen consisted of a sausage-shaped (3.5 x 2.0 x 1.2 cm), thinly-encapsulated mass of reddish-brown tissue. The cut surface had a mottled, vaguely nodular, yellowish-brown appearance. Microscopic examination revealed sheets of hematopoeitic elements, including myeloid, red cell and megakaryocytic lines, the latter showing Factor 8-related positivity. The final diagnosis was extramedullary hematopoiesis (EMH). A bone marrow biopsy performed as a result of the diagnosis showed a myeloproliferative disease and polycythemia vera. EMH in the spinal epidural space is a rare but treatable cause of progressive paraparesis in patients with a variety of hematological disorders. Since 1956 there have been more than 50 reported cases, most of which occurred in association with thalassaemia. In spinal cord compression secondary to EMH, the lesions are commonly localized to the mid-lower thoracic region.     

Cytologic features of pancreatobiliary neoplasm of duodenum

Small intestinal adenomas are uncommon. Majority of these occur in the region of the ampulla of Vater. Adenomas of the ampulla can be further subdivided into two types—intestinal and pancreatobiliary. While intestinal adenomas are more frequent, pancreatobiliary adenomas are rare. There is limited literature regarding the role of endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) in the diagnosis of ampullary/peri‐ampullary neoplasms. Here, we describe the cytologic features of a pancreatobiliary neoplasm of the duodenum that was sampled by EUS‐FNA. The aspirate was cellular and revealed cells with moderately abundant oncocytic cytoplasm. The nuclei were round with fine chromatin and focally prominent nucleoli. Although the concurrent biopsy showed no high‐grade dysplasia or invasive carcinoma, the EUS and imaging findings were highly suspicious for invasion. A broad differential diagnosis is under consideration for a duodenal mass that encompasses neoplasms of the biliary tract, pancreas, duodenum, and ampulla of Vater. To our knowledge, cytologic features of a pancreatobiliary neoplasm of the duodenum have not been previously reported. Our case highlights the features seen on cytology with histologic correlation in the hopes of elucidating features to better characterize these lesions.