Mucosal Schwann Cell Hamartoma of the Appendix: Expanding the Differential for Gastrointestinal Bleeding.

Mucosal Schwann cell hamartomas (MSCH) are rare benign tumors typically found in the colorectal region. We present the case of an 87-year-old man with a history of mucosa-associated lymphoid tissue lymphoma who developed symptomatic gastrointestinal bleeding due to an appendiceal MSCH. The patient's ongoing melena and anemia led to further evaluation. Subsequent colonoscopy revealed active bleeding from the appendiceal orifice with hemostasis achieved using epinephrine injection. A laparoscopic appendectomy confirmed MSCH through histopathology and immunohistochemical staining. Given its rarity, this case underscores the importance of considering MSCH in unexplained gastrointestinal bleeding and demonstrates its potential to be a symptomatically significant entity.