Melanosis Ilei

Abstract

A 65-year-old woman was admitted with a 2-week history of edema of the lower extremities in 2010. Her past medical history was significant for gastrointestinal stromal tumor of the stomach, and she had a partial gastrectomy in 2005. In 2008, she was diagnosed with a local recurrence, and a total gastrectomy was performed, with subsequent daily administration of imatinib. There was no sign of tumor recurrence during a 32-month follow-up period. This patient had a long history of constipation and extensive use of laxatives containing anthraquinone. Physical examination revealed anemia and pitting edema of the lower limbs. Laboratory investigations indicated a total white blood cell count of 4570, hemoglobin of 8.8 g/dL, and hypoalbuminemia (2.6 g/dL). Liver and renal function was normal and urinalysis showed no protein. Upper endoscopy was not indicative. Colonoscopy revealed diffuse dark pigmentation throughout her colon, consistent with melanosis coli (Figure A). A colonic biopsy specimen showed pigmented macrophages in the lamina propria. Subsequent double-balloon endoscopy revealed diffuse and dark punctuate pigmentation in the ileal mucosa (Figure B). Biopsy of the affected areas revealed deposition of the dark granular pigment inside the macrophages in the villous stroma (Figure C). Iron stain was negative, indicating that the dark granular pigment was not hemosiderin. Consequently, we supposed that the patient's hypoalbuminemia was imatinib-related. After cessation of imatinib therapy, the serum albumin level rose and then stabilized at a normal level. Melanosis coli is the common condition during endoscopic evaluation. Chronic use of laxatives containing anthraquinone directly affect epithelial cells, inducing the production of lipofuscin, which results in the dark pigmentation seen in macrophages.1Walker N.I. Bennett R.E. Axelsen R.A. Melanosis coli A consequence of anthraquinone-induced apoptosis of colonic epithelial cells.Am J Pathol. 1988; 131: 465-476PubMed Google Scholar Melanosis can affect other parts of the gastrointestinal tract. Melanosis duodeni is a rare condition that has been associated with hypertension, gastrointestinal bleeding, and chronic renal failure.2Yen H.H. Chen Y.Y. Soon M.S. Pseudomelanosis duodeni: an unusual finding from upper gastrointestinal endoscopy.Clin Gastroenterol Hepatol. 2009; 7: e68Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Certain medications such as hydralazine, furosemide, and ferrous sulfate have also been implicated in this condition. Melanosis of the small intestine is an extremely rare condition, but melanosis ilei in patients given oral iron therapy has been described,3Almeida N. Figueiredo P. Lopes S. et al.Small bowel pseudomelanosis and oral iron therapy.Dig Endosc. 2009; 21: 128-130Crossref PubMed Scopus (7) Google Scholar with hemosiderin pigment present in those cases. Charcoal components, as a consequence of chronic ingestion of charcoal, also have been reported to cause melanosis of the small intestine,4Kim J. Hwang J.K. Choi W.S. et al.Pseudomelanosis ilei associated with ingestion of charcoal: case report and review of literature.Dig Endosc. 2010; 22: 56-58Crossref PubMed Scopus (10) Google Scholar but our patient had not consumed such material. Because she had a history of chronic use of laxatives, and characteristics of the pigment were identical in the ileum and colon, we suppose that long-term use of anthraquinone-containing medications could have been the major cause of pigment deposition of the ileum. Despite the benign aspects of melanosis ilei, the increasing use of double-balloon endoscopy to evaluate small intestinal diseases suggests that gastroenterologists should be aware of its existence.