In year 1954, Dubin and Johnson reported a first time a case of chronic jaundice with unknown pigment in the liver [7]. Sprinz and Nelson, in the same year of 1954, confirmed persistent non-hemolytic hyperbilirubinemia four patients. This hyperbilirubenemia was characterized by deposition of lipochrome-like pigment in the liver cells and this syndrome was named as the Dubin Johnson syndrome.[8]
This syndrome is an autosomal recessive disorder caused by MRP2 (Multidrug resistance protein 2), protein dysfunction. [9] This originates from a mutation in the ABCC2 gene which provides instructions to produce a protein called MRP2. This MRP2 acts a transporter protein for excretion of conjugated bilirubin from liver cells into the biliary ducts .[10]Conjugated bilirubin accumulates in the hepatocyte and there may be elevation in serum bilirubin levels .This syndrome occurs among all races, nationalities, and equally among both male and female, although it manifests earlier in men. Dubin Johnson syndrome typically manifests in adolescence or young adult age. [11] Around 80 to 99% of people with Dubin–Johnson syndrome have jaundice, abnormal urinary color, conjugated hypebilirubinemia and biliary tract abnormality.[12] Rarely, patients may present with abdominal pain, fatigue, liver enlargement, or dark urine.[13, 14]
The conjugated hyperbilirubinemia and dark liver, varying in color from black, dark green, purple to slate gray is characteristic feature of DJS.[15, 16] The black liver is solely unique of this disorder and is due to deposition of coarsely dark granular pigment in centrilobular liver cells. In DJS, despite chronic hyperbilirubenemia ,black liver exhibits normal architectural pattern of parenchymal of liver. Abnormality of the gastric mucosa is present in 30 to 79% of people with DJS.[17]
The conjugated bilirubin is in the range of 2 to 5 mg/dl ,with no other liver enzyme found elevated and no hepatic dysfunction seen.[18] The coproporphyrin levels in urine of DJS cases consists mostly of coproporphyrin I, whereas coproporphyrin III is most common in normal urine.[19]
The diagnosis of DJS is confirmed by Laboratory and Radiological tests .Among former performing the Bromsulphalein test is done. Various radiological tests being done for confirmation DJS include oral cholecystography, HIDA scan. [20]. The gold standard test for diagnosing DJS is liver biopsy is.[21]On microscopy, there is presence of the brown pigment granules in the centrilobular hepatocytes. The definitive diagnosis for confirming DJS is molecular genetic testing of the ABCC2 gene [22]
Number of pathological conditions for DJS included for differential diagnosis incorporate obstructive jaundice, Gilbert's syndrome Rotor’s syndrome, Crigler-Najjar syndrome, Chronic liver injury, pregnancy with acute fatty liver and HELLP syndrome.[23]
The condition is benign, has no long-term consequences and does not require any treatment. Rarely, DJS may progress to cholestasis of liver .There is no risk of fibrosis or cirrhosis seen and rarely requires any treatment for this.[24].
All previous cases where black liver was diagnosed intraoperatively had routine laparoscopic cholecystectomy, none had no preoperative diagnosis[25,26 ] .Our case was par with all similar cases reported with black liver diagnosed incidentally on laparoscopic cholecystectomy.