Authors: Maha M Maher (corresponding author) ; Mahmoud I Nassar 
The "black esophagus" is an extremely rare endoscopic finding since its first description by Golden berg in 1990 . Although black discoloration can be caused by malignant melanoma, melanosis, pseudomelanosis, acanthosis nigrigans, or coal dust deposition, the term "black esophagus" most often refers to acute esophageal necrosis "AEN" . AEN is frequently associated with severe clinical conditions such as hypovolemic shock, septic shock, hyperglycemia, hypothermia, and liver disease, with impairment of the hemodynamic equilibrium of the patient. What is known about black esophagus is based primarily on case reports and small case series. In the present report we describe the clinical, endoscopic and histopathological characteristics of a patient with a diagnosis of ANE.
A 63 - years old man, with diabetes mellitus type II, arterial hypertension and chronic obstructive pulmonary disease was admitted to internal medicine department suffering from dyspnea, cough and expectoration. Initial physical examination revealed a patient with poor general condition, normotensive, pulse 92 b.p.m, temperature was 37.8[degrees]C. Patient suddenly desaturated ; O2 saturation 78%, blood pressure decreased to 80/40, patient transferred to ICU, connected to mechanical ventilator. laboratory investigation revealed a state of acute renal failure. At this point a significant amount of coffee ground material (about 500 CC) was drained through nasogastric tube. Hemoglobin 9.3 g/dL, leukocytes 23 cells/mm 3, platelets 201 U/L, sodium 141 mEqu/L, potassium 4 mEqu/L, Glu 11.5 mmol/L, BUN 16.2, creatinine 254, urine culture revealed pseudomonas aereogenosus.
Upper GIT endoscopy showed : a blackened and friable esophageal mucosa mostly at lower 2/3 with gradual fading of darkness in upper 1/3 (figure 1), two small nodules presented at cardioesophageal junction (figure 2), biopsies taken from esophageal mucosa and nodules. Superficial gastric erosions with stigmata of recent bleeding, duodenum appears normal.
Figure 1: Black esophageal mucosa of lower 2/3. [figure omitted]
Figure 2: Two small nodules at cardioesophageal junction. [figure omitted]
Histopathology: Sections show fragments of esophageal squamous epithelium and antral mucosal tissue, they feature intraepithelial acute inflammatory cellular reaction, edema of the antral mucosa. It contains fragments of neoplastic growth formed of small separate rounded cell infiltrating the esophageal subepithelial and the antral...