Asymptomatic Colonic Mastocytosis

Abstract

Purpose: Mastocytosis is characterized by abnormal proliferation and accumulation of mast cells in various organs and tissues. The clinical presentation is variable and can be localized, such as skin rash to systemic symptoms, depending on organ system involvement. 70 to 80% of patients with systemic mastocytosis are found to have gastrointestinal (GI) symptoms, and the GI lesions may involve any part of the digestive tract, from the esophagus to the rectum. We present an interesting case of a 68-yearold asymptomatic female who was found to have multiple polypoid lesions in the sigmoid colon, the descending colon, the ascending colon, and the cecum on routine screening colonoscopy. The histopathological examination of the lesion showed mastocytosis with positive markers for CD 25, CD 68, CD 117, and mast cell tryptase. The immunophenotype of the mast cells (CD25) was atypical, and showed many aggregates containing more than 15 mast cells, which fulfills the diagnostic criteria of World Health Organization for systemic mastocytosis. The most common GI symptom in systemic mastocytosis is abdominal pain, followed by diarrhea, nausea, and vomiting. However, in our case, the patient denied having any symptom, skin lesion, or allergic manifestation on the initial --as well as follow-up-- visits. Currently, there is no curative treatment for systemic mastocytosis, and no well-accepted consensus or guideline regarding follow-up endoscopy for asymptomatic gastrointestinal mastocytosis, such as in our case. However, close follow-up of the patient to monitor the development of symptoms is very important.FigureFigure