Epithelioid GIST differential diagnosis

This report describes the cytologic features of a recently described MXD4::NUTM1-rearranged colonic sarcoma metastatic to the midclavicular soft tissue. Thirteen years ago, a 65-year-old woman presented with a cecal mass and subsequent liver mass. The cecal mass was diagnosed as malignant undifferentiated spindled and epithelioid neoplasm based on morphology and lack of tumor immunoreactivity with a panel of epithelial, smooth muscle, skeletal, melanoma, hematologic, and GIST markers. The liver mass showed morphologic and immunophenotypic similarity to the epithelioid component of the patient's cecal mass, albeit devoid of the spindled component...

BACKGROUND: Perivascular epithelioid cell tumors (PEComas) encompass a group of rare mesenchymal neoplasms, with dual melanocytic and muscular differentiation. Hepatic PEComas are rare and difficult to diagnose, and their behavior is still unclear. MATERIALS AND METHODS: Herein, we report a total of five cases of hepatic and perihepatic PEComas over a period of the last 5 years from our and collaborating center's archive. A detailed histological evaluation was done...

Gastrointestinal stromal tumors (GISTs), although rare, are the most common mesenchymal neoplasms of the gastrointestinal tract. Their potential for malignancy underscores the significance of identifying them through cytomorphologic findings and pertinent immunohistochemical markers. GISTs can emerge anywhere along the gastrointestinal tract with a predilection for the stomach. The clinical manifestations vary from nonspecific abdominal symptoms to incidental discovery during diagnostic interventions for unrelated signs and symptoms...

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract with a broad morphological spectrum. Although epithelioid GISTs account for 20% of GISTs, their morphological features may pose a diagnostic pitfall for pathologists due to their morphological similarities to poorly differentiated adenocarcinoma and lymphoma. CASE PRESENTATION: Herein, we report a 65-year-old male patient with gastric epithelioid GIST misdiagnosed as adenocarcinoma for four years...

Background: Gangliocytic paraganglioma (GP) is a rare tumor that most commonly arises from the duodenum and is characterized pathologically by 3 cell types: epithelioid, spindle, and ganglion cells. GP is often difficult to differentiate from a neuroendocrine tumor on the basis of preoperative imaging, and the diagnosis is based on final histopathologic and immunohistochemical analysis. Case Report: We report the case of a 28-year-old male who presented with pain in the abdomen, bilious vomiting, and weight loss...

Preferentially expressed antigen in melanoma (PRAME) immunohistochemistry is currently used in pathology for the assessment of melanocytic neoplasms; however, knowledge of its expression patterns in soft tissue tumors is limited. PRAME immunohistochemistry (clone QR005) was assessed on whole tissue sections of 350 soft-tissue tumors and mimics (> 50 histotypes). PRAME immunoreactivity was evaluated as follows: 0 "negative" (0% positive cells); 1+ (1-25% positive cells); 2+ (26-50% positive cells); 3+ (51-75% positive cells), and 4+ "diffuse" (> 75% positive cells)...

Neuroendocrine neoplasms represent a heterogeneous group of rare tumors, more frequently arising from gastroenteropancreatic tract and lungs. At the time of diagnosis, 20% of cases are metastatic, and 10% of cases are considered as cancer of unknown primary origin. Several immunohistochemical markers are routinely used to confirm the neuroendocrine differentiation, first among all Synaptophysin and Chromogranin-A; on the other hand, different immunohistochemical markers are used to establish primary anatomical site, as TTF1, CDX2, Islet-1 and Calcitonin, but no marker is available in order to distinguish among different sites of the digestive tract...

BACKGROUND: Malignant perivascular epithelioid cell tumors (PEComas) are exceedingly rare malignant mesenchymal neoplasms with characteristic morphological and immunohistochemical (IHC) patterns. However, some malignant PEComas are poorly differentiated with atypical histopathological features, making a definitive diagnosis difficult. PEComas are most commonly found in females and often show either TSC1 or TSC2 alterations, which result in the activation of the mTOR pathway, or TFE3 fusions...

OBJECTIVE: To determine the significance of the TLE-1 expression in GISTs, and evaluate the predictive value of TLE-1 expression in patient survival. STUDY DESIGN: An observational study. Place and Duration of the Study: The archives Department of Pathology, Başkent University, Adana, Turkey, between 2010 and 2021. METHODOLOGY: Fifty patients diagnosed with GIST were included in the study. The diagnosis of GIST was confirmed in all tumours with an immunohistochemistry panel comprising CD117, DOG1, CD34, SMA, S100, and Ki67...

Objective: To investigate the clinical significance of pathological diagnosis and genetic abnormalities detection of gastrointestinal stromal tumor (GIST) using endoscopic biopsy. Methods: Patients with GIST diagnosed by endoscopic biopsy (from January 1st, 2016 to August 1st, 2018, at Zhongshan Hospital, Fudan University) were included in this study. This retrospective study evaluated the histopathologic and immunohistochemical (IHC) features, genetic abnormalities of the tumors and the treatment and clinical course of the patients...

BACKGROUND: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm arising in the stomach. However, a number of other rare mesenchymal neoplasms do occur at this anatomic site, which often presents a diagnostic challenge for cytopathologists on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Our study aims to selectively present the clinico-radiologic and cytopathologic characteristics of these rare "non-GIST" neoplasms, as well as their differential diagnoses...

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract, originating from structures differentiating towards Cajal cells. Due to their morphology and localization, the extragastrointestinal stromal tumors (EGISTs) can be a diagnostic challenge. We investigated a series of 51 EGISTs diagnosed in our institutions, aiming to explore the immunophenotypes and to analyze the process and the utility of the antibodies required for a positive diagnosis. Immunohistochemical examinations were done for pan-cytokeratin (pan-CK), Ki67, discovered on GIST1 (DOG1) protein and platelet-derived growth factor receptor alpha (PDGFRA), as necessary...

Follicular dendritic cell (FDC) sarcoma is an uncommon tumor of the liver with only 30 previous cases reported in the English literature. Histopathological examination is the gold standard for the diagnosis of FDC sarcoma although the diagnosis is often missed because of its rarity. It usually presents with spindle-cell morphology although epithelioid/biphasic morphology is also well-known. This morphological variation can also pose a diagnostic challenge. We discuss a case of unresectable hepatic FDC sarcoma in an adult male who was diagnosed in core biopsy...

OBJECTIVE: Most pancreatic tumors are epithelial, and, among these, more than 90% are of ductal origin. However, a variety of mesenchymal tumors may involve the pancreas and may manifest different clinicopathological characteristics. The literature on mesenchymal tumors in the pancreas is largely limited to individual case reports or analyses of small series, predominantly focusing on radiologic features. MATERIAL AND METHOD: Authors' institutional and consultation databases were reviewed to identify the mesenchymal tumors involving the pancreas...

DOG1 (Discovered on GIST1) is a voltage-gated calcium-activated chloride and bicarbonate channel that is highly expressed in interstitial cells of Cajal and in gastrointestinal stromal tumors (GIST) derived from Cajal cells. To systematically determine in what tumor entities and normal tissue types DOG1 may be further expressed, a tissue microarray (TMA) containing 15,965 samples from 121 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry...

Undifferentiated soft tissue sarcomas (USTS) are described in the current World Health Organization Classification of Soft Tissue and Bone Tumours as those showing no identifiable line of differentiation when analyzed by presently available technologies. This is a markedly heterogeneous group, and the diagnosis of USTS remains one of exclusion. USTS can be divided into four morphologic subgroups: pleomorphic, spindle cell, round cell and epithelioid undifferentiated sarcomas, with this combined group accounting for up to 20% of all soft tissue sarcomas...

INTRODUCTION: Gastrointestinal angiosarcomas are rare and represent less than 1% of all gastrointestinal tract malignancies, with most occurring in the stomach and small intestine. Occurrence in the colorectal segments is considered extremely rare. Case Report . We describe the case of a 61-year-old male with multiple primary angiosarcomas of the colon who presented with fever and abdominal pain. The patient was initially hospitalized and treated as having an infectious disease. A multislice computed tomography (MSCT) scan revealed multiple soft tissue tumors in the region of the left iliopsoas and gluteus medius muscles...

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare malignant primary gastrointestinal mesenchymal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology. In the context of FNA, the diagnosis requires a cell block and the use of significant resources including immunohistochemical stains and molecular testing. The differential diagnosis of GNET includes clear cell sarcoma (CCS), gastrointestinal stromal tumor (GIST), gastric schwannoma, metastatic melanoma, malignant perivascular epithelioid cell tumor (PEComa) and granular cell tumor, among others...

Objective: To investigate the clinicopathological features, immunohistochemical characteristics, differential diagnosis and prognosis of gastric SWI/SNF-complex deficient undifferentiated/rhabdoid carcinomas. Methods: Two cases of gastric SWI/SNF-complex deficient undifferentiated/rhabdoid carcinoma were collected at Fudan University Shanghai Cancer Center, Shanghai, China from 2017 to 2018. The clinicopathological characteristics were analyzed. Hematoxylin and eosin, and immunohistochemical stains were performed, and the relevant literatures were reviewed...

Plexiform fibromyxoma (PF) is a very rare mesenchymal neoplasm of the stomach that was first described in 2007 and was officially recognized as a subtype of gastric mesenchymal neoplasm by World Health Organization (WHO) in 2010. Histologically, PF is characterized by a plexiform growth of bland spindle to ovoid cells embedded in a myxoid stroma that is rich in small vessels. The lesion is usually paucicellular. While mucosal and vascular invasion have been documented, no metastasis or malignant transformation has been reported...