Duodenal pseudomelanosis (pseudomelanosis duodeni): a rare endoscopic finding

Abstract

Duodenal pseudomelanosis (or pseudomelanosis duodeni) is a rare benign
condition characterized by black-brown speckled pigmentation of the duodenal
mucosa. Collections of pigment−laden macrophages are found in the tips of
duodenal villi. The pigment is thought to be mostly composed of ferrous sulfide.
Histochemichal stains for iron (Perl’s prussian blue) or melanin (Masson-
Fontana) may be positive, but are usually negative or unpredictable. Duodenal
pseudomelanosis occurs predominantly in middle-aged to old adults and
more commonly in females. It is associated with chronic renal failure, arterial
hypertension, diabetes mellitus and gastrointestinal bleeding. Medications such
as ferrous sulfate, hydralazine, propranolol, hydrochlorothiazide and furosemide
are thought to play a role as well. We report a case of a 86-year-old female
who presented with a history of watery diarrhea and melena. The patient had a
history of high blood pressure and ischemic stroke episodes. She was on multiple
medication including hidralazine, captopril, hydrochlorthiazide and aspirin. She was
dehydrated, her blood pressure was 96 × 60 mmHg and neurologic examination
showed complete left hemiplegia with central VII nerve palsy. Laboratory tests
showed normal serum electrolytes and renal function. Hemoglobin level was
10.7 g%. An upper endoscopy showed multiple diminutive black spots throughout
the distal duodenal bulb and second portion. Histology showed multiple foci of
a brown-black granular pigment inside macrophages within the tips of the villi
(pseudomelanosis). Stains for iron and melanin were negative. She was treated
with omeprazol, parenteral fluid replacement with saline and partial fasting. After
complete recovery she was discharged for ambulatory follow up.