Malignant atrophic papulosis: Two case reports.

BACKGROUND: Malignant atrophic papulosis is a rare and potentially lethal thrombo-occlusive microvasculopathy characterized by cutaneous papules and gastrointestinal perforation. The precise pathogenesis of this disease remains obscure. CASE SUMMARY: We describe the case of a 67-year-old male patient who initially presented with cutaneous aubergine papules and dull pain in the epigastrium. One week after symptom onset, he was admitted to the hospital for worsening abdominal pain. Exploratory laparotomy showed patchy necrosis and subserosal white plaque lesions on the small intestinal wall, along with multiple perforations. Histological examination of the small intestine showed extensive hyperemia, edema, necrosis with varying degrees of inflammatory reactions in the small bowel wall, small vasculitis with fibrinoid necrosis and intraluminal thrombosis in the mesothelium. Based on the mentioned evidence, a diagnosis of malignant atrophic papulosis was made. We also present the case of a 46-year-old man with known cutaneous manifestations, abdominal pain, nausea and vomiting. His physical examination showed positive rebound tenderness. A computed tomography scan revealed free intraperitoneal air. He required surgical intervention on admission and then developed an esophageal perforation. He ultimately died of a massive hemorrhage. CONCLUSION: In previously published cases of this disease, the cutaneous lesions initially appeared as small erythematous papules. Subsequently, the papules became porcelain-white atrophic depression lesions with a pink, telangiectatic peripheral rim. In one of the patients, the cutaneous lesions appeared as aubergine papules. The other patient developed multiple perforations in the gastrointestinal tract. Due to malignant atrophic papulosis affecting multiple organs, many authors speculated that it is not a specific entity. This case series serves as additional evidence for our hypothesis.

In vitro toxicity of multi-walled carbon nanotubes in C6 rat glioma cells.

The present study aimed to evaluate the potential toxicity and the general mechanism involved in multi-walled carbon nanotubes (MWCNT)-induced cytotoxicity in C6 rat glioma cell line. Two kinds of MWCNT, which were coded as MWCNT1 (measured 10-20 nm in diameter and 2 µm in average length) and MWCNT2 (measured 40-100 nm in diameter and 10 µm in average length), were used in this study. To elucidate the possible mechanisms of cytotoxicity induced by MWCNT, MTT assay and flow cytometry analysis for apoptosis and cell cycle, MDA and SOD assays for oxidative stress were quantitatively assessed. The exposure of C6 rat glioma cells to different sizes of two kinds of carbon nanotubes at concentrations between 25 and 400 µg/ml decreased the cell viability in a concentration- and time-dependent manner. The exposure of C6 rat glioma cells to MWCNT (200-400 µg/ml) resulted in a concentration dependent cell apoptosis and G1 cell cycle arrest, and increased the level of oxidative stress. Results demonstrate that smaller size of MWCNT seems to be more toxic than that of larger one. MWCNT-induced cytotoxicity in C6 cells is probably due to the increased oxidative stress.