Gastric glomus tumor diagnosed by fine needle aspiration of the stomach: A report of two cases and review of the literature

Abstract

Glomus tumors make up 1% of stromal tumors of the stomach. Radiologic diagnosis of glomus tumors can be challenging as they share imaging characteristics with other neuroendocrine tumors and gastrointestinal stromal tumors. Endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) has been reported as a useful method for the evaluation of gastrointestinal lesions. We report two cases of gastric glomus tumors in which EUS‐FNA diagnosis was challenging. Cytologically, neoplastic cells were round to oval, uniform, bland appearing epithelioid cells with delicate chromatin and inconspicuous to vague nucleoli. Both samples lacked worrisome features such as high nuclear grade, high mitotic rate, and necrosis. Neoplastic cells were negative for Cam5.2 and AE1/AE3 with focal expression of synaptophysin in one of the cases. A definitive diagnosis was not made based on FNA. Familiarity with glomus tumors in the GI system and procurement of adequate material for cell block allowing the use of immunohistochemistry may allow an accurate preoperative diagnosis.

Presentación atípica de tumor glómico en vía aérea: reporte de caso y revisión de literatura

“…Con mayor aumento al microscopio se alcanzan a ver los vasos sanguíneos de pequeño calibre rodeados por células glómicas con un fondo de tejido estromal. En la zona periférica, se pueden ver bordes de componentes de matriz extracelular, como bordes de colágeno, rodeado de otros vasos y tejido nervioso 14 , características similares a las referidas en nuestro caso.…”

Mimickers of neuroendocrine tumors on endoscopic ultrasound‐guided fine‐needle aspirate material: Need for caution

“…Although glomus tumors have been documented to express synaptophysin, they are usually negative for chromogranin. [15][16][17][18] One common theme in our cases was that we relied mainly on synaptophysin staining for a neuroendocrine diagnosis. Although fairly sensitive, synaptophysin is often positive in a wide variety of nonneuroendocrine tumors, especially when these tumors are of higher grade.…”

“…The monotonous nature of lesional cells, their cohesiveness, distinctive hemangiopericytoma‐like vascular pattern and characteristic immunostain profile (INSM1, chromogranin and cytokeratin negative, and calponin and SMA positive) helped distinguish glomus tumor from a well‐differentiated neuroendocrine tumor. Although glomus tumors have been documented to express synaptophysin, they are usually negative for chromogranin 15–18 …”