Gastrointestinal Glomus Tumors: Outcomes and Management Experiences

Introduction: Glomus tumors typically involve peripheric tissues, only rarely being reported in the gastrointestinal tract. We present our institutional experience with gastrointestinal glomus tumors. Methods: A retrospective review of all gastrointestinal glomus tumors was conducted across three Mayo Clinic Sites from 2001 to 2021. Descriptive statistics were used. Results: Five men and 4 women were identified, with a median age of 53 years (interquartile range [IQR] 44.3-69.15 years). Four patients presented abdominal discomfort, 3 anemia or bleeding, 2 were incidentally found. All CT scans showed masses thought to represent gastrointestinal stromal tumors or neuroendocrine tumors. Seven patients underwent preoperative endoscopy, including 5 ultrasonography. All tumors were localized at the stomach antrum. Endoscopic biopsies (7 patients) were interpreted as glomus tumor (n = 3), neuroendocrine tumor (n = 2) and non-diagnostic (n = 2). Patients underwent open (n = 3) or minimally invasive (n = 6) margin-negative resection by wedge resection (n = 5) or distal gastrectomy (n = 4). No nodal metastases were identified. Median tumor size was 2.5 cm (IQR 13-34 cm). Typical morphological and immunohistochemical features of glomus tumors were identified; tumors were classified as histologically benign (n = 7), histologically malignant (n = 1), and of uncertain malignant potential (n = 1). Next-generation sequencing on one tumor identified a CARMN::NOTCH2 fusion. Clinical follow-up (median 14.9 months; IQR 10-86 months) showed all patients to be symptom-free, without recurrences. Two patients died from unrelated causes. No patients received adjuvant therapy. Conclusion: Our 20-year experience with gastrointestinal glomus tumors confirms their rarity and generally indolent clinical behavior. As some gastrointestinal glomus tumors display malignant behavior despite benign histology, long-term follow-up is warranted.