Clinical Case Summary

Introduction: Mastocytosis is an uncommon hematopoietic neoplasm characterized by clonal proliferation of atypical mast cells. The clinical manifestations of mastocytosis are heterogeneous,ranging from limited cutanous involvement to aggressive disease with various levels of extra cutanous multi-organ involvement. Most cases of mastocytosis are indolent, usually cutanous or indolent systemic mastocytosis (SM). Aggressive SM is a rare and often fatal disease. Gastrointestinal involvement in aggressive SM presents with non specific symptoms and the final diagnosis depends on the pathology. Herein, we present a special case of colonic mastocytosis
Clinical case: We report a case of 66 years old female patient who presented with chronic abdominal pain not responding to treatment. On physical examination showed abnormal abdominal pigmentation and reported that skin biopsy previously revealed urticaria pigmentosa. Laboratory investigations were unremarkable. Colonscopy was planned and showed diffuse reddish mottling of cecum and ascending colon. Multiple biopsies were taken and histopathological examination revealed focal crypt architectural distortion. The lamina showed moderate inflammatory cellular infiltrate. These are formed of lymphocytes and plasma cells with excess eosinophils > 100/HPF. Esinophilic cryptitis is seen. Subtle population of scattered ovoid cells with rounded ovoid nuclei are seen. Slide stained for CD117 revealed positive reaction highlighting frequent mast cells. Moderate diffuse colitis with frequent mast cells and excess eosinophils > 100/HPF. Picture is suggestive of mastocytosis involving colon. The patient started imatinib and prednisone and long term follow up showed complete relieve of abdominal pain.