Acute esophageal necrosis (AEN) secondary to chemotherapy (“moth-eaten black esophagus”)

A 60-year-old female with prior history of stage I non-Hodgkin lymphoma and myelodysplastic syndrome secondary to acute myeloid leukaemia presented on day 15 after allogeneic stem cell transplantation with febrile neutropenia, vomiting, acute epigastric pain, dysphagia, tachycardia, hypotension and marked clinical deterioration. She also referred to an episode of self-limited haematemesis.

CT scan performed 2 days before the onset of symptoms showed normal oesophagus (Fig. 1 a, b). Due to renal failure and to the abrupt clinical deterioration of the patient, a non-contrast CT scan was performed, which revealed a dilated and thickened distal oesophagus (4.5 mm thick, extending along 10 cm), with preservation the gastroesophageal junction. Small air-bubbles were identified within the oesophagal wall (Fig. 2 a, b). It was called the “moth-eaten black oesophagus” sign. There was no evidence of mediastinitis. Bilateral pleural effusion and bilateral perihilar opacities with thickened interlobular septa in keeping with pulmonary oedema were also noted (Fig. 3 a, b).

With the presumptive radiological diagnosis of acute oesophagal necrosis (AEN), an emergency gastroscopy was performed, which showed esophagitis and circumferential black friable mucosa in distal oesophagus. Multiple linear tears were also identified (Fig 4 a, b).

Acute oesophagal necrosis (or “black oesophagus”) (AEN) is an extremely rare entity, with a prevalence of 0.001 to 0.2% in different published endoscopic series [1]. On endoscopy, this disorder is characterized by diffuse and circumferential involvement of a black-appearing distal oesophagus, with preservation of the gastroesophageal junction (GEJ) [2]. Male and elderly patients with multiple medical comorbidities are at increased risk of developing AEN.

Although the pathophysiology of the disease is still unclear, it appears to arise from the combination of oesophagal ischemia, impaired mucosal barrier systems, and the reflux injury caused by the chemical content of gastric secretions. Other associations, such as infections (cytomegalovirus, candida, herpes virus, klebsiella), drugs (broad-spectrum antibiotics, chemotherapy), drug abuse, mechanical obstructions or metabolic disorders have also been reported [3, 4].

Signs of upper gastrointestinal bleeding (hematemesis, emesis in coffee grounds and melena), represent almost 90% of cases in the initial clinical presentation. Other symptoms such as dysphagia, vomiting, epigastric or pleuritic pain are more nonspecific. Sepsis is a typical associated clinical condition.

Diagnosis is based on gastroscopy [5]. Radiological studies, such as chest X-ray and chest CT have classically been considered complementary tools to evaluate possible complications, including oesophagal perforation, pneumomediastinum, and development of mediastinitis [6]. Oesophagal necrosis is characterized by dilation and wall thickening of the distal oesophagus, with preservation of the GEJ. On CT studies, small air-bubbles can be seen within a thickened wall (Fig. 1b, d) [7, 8], taking on the appearance of a “black moth-eaten oesophagus”.

Other signs like blurring of the oesophagal wall and the perioesophageal fat (on unenhanced images) and postcontrast oesophagal-wall enhancement with definition of transmural necrosis are very specific of AEN, when identified together (two of three are present) CT has shown to be superior to endoscopy for treatment stratification of these patients [9].

Emergency gastroscopy is the gold standard for diagnosis. It will show the classic black appearance of the necrotic distal oesophagal mucosa (“black oesophagus”, Fig. 3a), with multiple linear tears (Fig. 3b) or longitudinal ulcers. Confirmation and aetiologic cause can be ascertained by oesophagal biopsy [10].

The development of AEN carries a generally poor prognosis. Oesophagal perforation is the most serious complication. Treatment depends on clinical experience. In most cases, initial management consists of volume expansion for patient stabilization and treatment of underlying diseases. Other options include gastric acid suppression with high-doses of intravenous proton pump inhibitors [11].

Radiologists must be aware of the diseases that affect the oesophagus and consider rare entities, such as AEN, in the appropriate clinical context. Dilation and thickening of the walls of the distal oesophagus with small air bubbles ("moth-eaten black oesophagus" sign) can be seen on unenhanced chest CT scans in patients with AEN [12].