Aryal SC, and Yuan L. Gastric Glomus Tumor on EUS-FNA-Based Cytology; Clinicopathologic and Immuno-Histochemical Features of Four Cases Including a Case with Associated MIR143HG-NOTCH2 Fusion Gene. J Am Soc Cytopathol 2022; 11(6):S40-S41.
J Am Soc Cytopathol
Introduction: Gastric glomus tumor (GT) is a rare submucosal tumor for which preoperative diagnosis can be challenging. We report cytomorphological and immunohistochemical (IHC) features of four gastric GT cases diagnosed by endoscopic ultrasound guided fine needle aspiration (EUS-FNA) cytology.
Materials and Methods: Files were searched to identify GT diagnosed on EUS-FNA between 2018 and 2021; four cases were found, three with rapid on-site evaluation (ROSE).
Results: A total of 4 cases (3:1 M:F) were included (mean age: 60 years). Three GTs were located in gastric antrum and one in gastric body. Size ranged from 2-2.5 cm (Table 1). Three patients presented with epigastric discomfort, and one had chest wall discomfort and recent history of lung adenocarcinoma. ROSE were performed on 3 cases, all indeterminate. The smears were moderate to highly cellular and showed loose clusters or fragment of small to medium sized bland tumor cells (Table 2). The cells had centrally located round to oval nuclei with inconspicuous nucleoli and moderate amount of eosinophilic to clear cytoplasm (Figure 1). Tumor cells with pale and dark stained nuclei were evenly distributed (Figure 1). Cell blocks revealed branching small vessels surrounded by small-medium cells with round-oval nuclei, inconspicuous nucleoli, and abundant eosinophilic cytoplasm (Figure 1). Neoplastic cells were positive for SMA, synaptophysin and negative for C-KIT, AE1/AE3 and S-100. CD34 was variably positive. Ki-67 was < 2%. For one case, the Fusion Panel - Solid Tumor (50 genes) revealed MIR143HG-NOTCH2 fusion gene (Figure 1, 2). One tumor was resected and consistent with benign GT, three were followed up clinically.
Conclusions: ROSE and cell blocks revealed cohesive bland round-oval tumor cells in GTs. The differential diagnosis on ROSE include neuroendocrine tumors and epithelioid spindle cell neoplasms. IHC and molecular studies can be helpful to assist in rendering an accurate preoperative diagnosis (Table 2).