Pseudomelanosis duodeni: associated with multiple clinical conditions and unpredictable iron stainability - a case series.

Pseudomelanosis duodeni is seen endoscopically as dark spots in the duodenal mucosa and is generally considered to be local deposition of iron from oral iron intake. However, pseudomelanosis duodeni may be identified histologically even before it becomes endoscopically evident; iron stainability within the mucosa is uneven and unpredictable, and multiple clinical conditions other than oral iron intake may be associated. We reviewed 17 adult patients with histologically detected pseudomelanosis duodeni, their endoscopic appearances, iron stainability, and clinical findings including oral iron and drug intake. Only 6/17 (35 %) had endoscopically apparent dark spots. Perl's iron stain was entirely positive in 18 %, partially positive in 64 %, and negative in 18 % of cases. History of oral iron was present in 76 % of patients, but other clinical conditions consistently associated were hypertension in 88 %, end stage renal disease in 59 %, and diabetes mellitus in 35 % of patients.