Melanosis intestini: case report

Experimentally induced melanin-like pigmentation (thesaurismosis) related to acorn ingestion in Nero Siciliano pigs

In this study, an experimental challenge was carried out by feeding Nero Siciliano pigs with acorn to evoke melanin-like pigmentation and support the hypothesis that it is caused by ingested material. Twelve pigs were studied, 6 fed with acorns and 6 fed commercial feed. At slaughter, all the animals fed on acorns showed black discolouration of almost all lymph nodes. The lymph nodes were normal in size and shape. Histochemical tests performed on tissues allowed us to identify and differentiate the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Our data, and the well-known steps of melanin formation, confirm that swine enzymes could act on phenolic substances found in acorns.

Pseudomelanosis ilei associated with ingestion of charcoal: case report and review of literature

Melanosis or pseudomelanosis of the gastrointestinal tract refers to an accumulation of pigment deposits in the gastrointestinal mucosa. Pigmentation can affect the entire gastrointestinal tract. Melanosis of the colon is not uncommon, but black pigmentation of the small intestine is extremely rare. We report a case of pseudomelanosis of the terminal ileum in a 52-year-old woman who had ingested a tablespoon of charcoal powder daily for 2 years. Numerous small and medium-sized irregular grayish black pigmentations mostly on the background of geographic light grayish discolored mucosa and some on the normal-looking mucosa were seen on the terminal ileum. The finding was similar to a cut surface of a dragon fruit and we named the lesion 'dragon fruit ileum'. Follow up endoscopy 10 months later revealed no significant change in the pigmentation. We could not search any English literature on this lesion. However, we could find three cases from two papers from Korea describing similar lesions after chronic charcoal ingestion and the papers were reviewed with a report of our case.

Melanosis ilei associated with chronic ingestion of oral iron

Melanosis can affect various parts of the gastrointestinal tract. Melanosis of the colon is not uncommon, while melanosis of the ileum is extremely rare. We report a case of melanosis ilei associated with chronic ingestion of oral iron (256 mg of ferrous sulfate once or twice daily for approximately 5 years) in a 32-year-old woman with end-stage renal disease. The findings of a colonoscopy, which was performed as a part of her medical checkup, were normal up to the cecum; however, numerous brownish-black punctuate pigmentations of the ileal mucosa were observed. Microscopic examination revealed hemosiderosis in the lamina propria of the ileal mucosa, particularly at the tips of villi. The diagnosis of melanosis (hemosiderosis) ilei was made based on the endoscopic and histological findings.

Acquired melanosis caused by acorn ingestion in the Nero Siciliano pig

In this study, an acquired pigmentation in Nero Siciliano pigs is reported and evaluated by a multidisciplinary approach to support the hypothesis it is caused by an ingested material. A total of 18 pigs were studied. Fourteen conventionally slaughtered animals showed black discoloration of lymph nodes. The lymph nodes were normal in size and shape but showed diffuse black discoloration of the cortex and medulla. Melanosis of fat was observed in 2 animals and was limited to the back. Histochemical tests performed on tissues enabled identification and differentiation of the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Stains for human melanoma, as well as S-100 protein, did not show any reaction. Histochemical methods for tyrosinase showed colorimetric patterns that confirmed the presence of the enzyme in acorns. The activity was mostly latent. A high tannin content was demonstrated, reaching about 76% of the total phenolic compounds. Our data, and the well-known steps on melanin formation, permit us to hypothesize that swine tyrosinase could act on phenolic substances found in acorns. Tyrosinase activation could take place in genetically predisposed swine after acorns are eaten, and this event could increase the biosynthesis and the anomalous storage of melanin.