A comparison of the ultrastructure of pigment granules in melanosis ilei and pulmonary lymph nodes

Abstract

Two cases of melanosis ilei were studied, in which grossly visible blackish pigmentation of the ileal mucosa was incidentally discovered at autopsy. Light microscopy showed that the pigment granules lay within macrophages in atrophic Peyer's patches. Ultrastructural studies showed that the pigment granules were heterolysosomes containing crystalline material, particles, granules and, occasionally, lipid droplets. The morphological similarity between these pigment granules and granules in pulmonary macrophages was established through ultrastructural studies of pulmonary lymph nodes obtained during routine autopsies. These data, plus results of past electron-probe X-ray analytic studies by us and others, leads us to conclude that the pigment granules in melanosis ilei contain exogenous material derived from inspired and ingested materials.

Melanosis Ilei Associated with Chronic Ingestion of Oral Iron

“…Although iron sulfide may be detected as melanosis duodeni, melanosis duodeni was not observed in our case. The reported pigments in melanosis ilei include silicates of aluminum and magnesium, hemosiderin, and charcoal 3,11,12. Ghadially et al11 showed that pigment granules in melanosis ilei are heterolysosomes which are similar to those seen in pulmonary macrophages by electronmicroscopical studies.…”

“…The reported pigments in melanosis ilei include silicates of aluminum and magnesium, hemosiderin, and charcoal 3,11,12. Ghadially et al11 showed that pigment granules in melanosis ilei are heterolysosomes which are similar to those seen in pulmonary macrophages by electronmicroscopical studies. Hemosiderin may produce gross pigmentation of the ileal mucosa in patients associated with episodes of gastrointestinal bleeding due to the long-term use of salicylates or in patients with hereditary hemochromatosis 3,12.…”