A Rare, Entirely Benign, Colonic Submucosal Lesion

Abstract

A submucosal colonic lesion is described as any mass-like protrusion into the lumen that is covered by normal appearing mucosa. The differential diagnosis of such lesions is broad and management can be challenging as endoscopic exam provides limited diagnostic utility and proximal colonic lesions are not typically accessible by endoscopic ultrasound. Further, the literature is sparse on definitive evaluation and surveillance of such lesions. We present a case of a patient presenting with abdominal pain and hematochezia incidentally found to have a cecal submucosal lesion. A 26 year old male with history of Hashimoto's thyroiditis presented to GI clinic with two months of abdominal pain and rectal bleeding. He denied other symptoms. Abdominal exam revealed left lower quadrant tenderness. Labs were normal. Colonoscopy revealed a 20 mm submucosal cecal mass and internal hemorrhoids. Cecal mass was biopsied with pathology showing chronic inflammatory cells including focally increased eosinophils. While the abdominal pain was thought to be functional and hemorrhoids were the etiology of rectal bleeding, there remained some uncertainty about the relationship of his autoimmune background, symptoms and eosinophils seen on pathology. CT abdomen showed a “surgically removed appendix,” despite no history of appendectomy. Repeat colonoscopy with deeper biopsies revealed inspissated mucin or fecalith; no malignancy. Given the size of the lesion, there remained concern for inadequate sampling, thus he was referred for surgical evaluation and underwent laparoscopic right hemicolectomy with pathology consistent with appendicolith. A fecalith is a hard mass of feces associated with increased risk of appendicitis. In this case, the fecalith was golf tee shaped which formed over time and arose from the distal end of the appendix, compressing against the cecum producing a submucosal cecal mass. The fecalith made the appendix invisible on imaging, explaining the CT finding; it did not cause appendicitis due to its very gradual accumulation. In our case, both colonoscopies yielded an uncertain diagnosis on pathology, which led to the patient undergoing surgical resection. The concern was if there was a tumor deep to the fecalith causing his symptoms,This case highlights the importance for further management recommendations for patients with incidentally found submucosal lesions with an endoscopically inconclusive pathologic diagnosis.