Looks like Adenoma, Feels like Adenoma, but Not an Adenoma: A Case of Primary Glomus Tumor of Colon

Abstract

Purpose: HOPI: A 59-year-old female with history of syringomyelia presented for outpatient screening colonoscopy. Methods: Colonoscopy: Complete until cecum with good bowel preparation. Patient had two diminutive sigmoid polyps removed by excisional biopsy and one sigmoid polyp about one cm, which was removed by snare cautery polypectomy. After snare polypectomy, there was some mild oozing, and hemostasis was achieved by cautery application. Results: Histopathology: Primary colonic glomus tumor with neoplastic cells positive for CD4, SMA, and vimentin. Given the location and unpredictable nature of progression, incidental colonic glomus tumor patient was recommended; PET scan of whole body as per oncology for further evaluation. PET scan was negative for any other glomus tumor or metastasis. Conclusion: Glomus tumors are mesenchymal tumors derived from the glomus body, seen commonly in the peripheral soft tissue with some potential for metastasis. Primary colonic glomus tumor is very rare, and its natural history and malignant potential is not well studied. There have been some rare cases of primary glomus tumor with metastasis arising from GI tract: stomach, duodenum, and small intestine. Malignant potential is determined by size > 2cm, atypical mitotic activity, nuclear atypia, and deep location. Even though wide excision/resection is curative, the recurrence rate of colonic glomus tumor is not well known. Due to lack of established guidelines, patient was recommended surveillance colonoscopy in three years or earlier, if clinically indicated.