RARE CASE OF UNANTICIPATED HEPATIC TISSUE IN THE THORAX MIMICKING A PULMONARY MASS IN A 49-YEAR OLD FEMALE

Abstract

Accessory liver tissue (ALL) is a very rare anatomical abnormality that is congenital with autosomal recessive inheritance, though in rare instances it has been reported after diaphragmatic trauma or surgery. Till date, only around 23 cases of ectopic liver tissue have been reported. This results in serious dilemmas in terms of diagnosis and management, with no specific guidelines available. Most cases of intrathoracic ALL end up in surgery and are diagnosed retrospectively. Most common site of ALL is in gall bladder. Intrathoracic accessory lobe of liver is an extremely rare variant of ALL, where autonomous islands of liver parenchyma are found in the thoracic cavity. The clinical significance of this condition is not well understood. It is suggested that intrathoracic heterotopic liver tissue has a higher risk of malignant transformation, due to inflammation resulting from bile and venous stasis. A 49-year-old woman presented to our hospital’s tobacco cessation clinic with a 24-year history of tobacco chewing and family history of malignancy. At initial visits, as she had no complaints or examination findings, only counselling was provided. However, at later visit, patient had complaints of pain in left cheek radiating to the ear and left sided neck pain. Clinical examination was unremarkable. No intraoral growth or precursor lesion was identified. Hence, she was evaluated by imaging studies. Computed tomography (CT) thorax incidentally identified a well-defined, heterogeneously enhancing pleural-based lesion of size 53.5 × 52.6 mm, located in right lower lobe, with no significant mediastinal or axillary lymphadenopathy. In view if her tobacco use and family history, a CT-guided biopsy of lung mass was done to rule out malignancy. Histopathological examination revealed benign hepatocytes arranged in cords and plates with intervening sinusoids. The hepatocytes exhibited mild macro vesicular steatosis and periportal lymphocytic infiltrates. There was no evidence of malignancy or lung parenchyma in the specimen, and deeper sections confirmed these findings. The impression was given as benign hepatic parenchyma with steatosis. The findings were further discussed with the pathologist, who confirmed that the biopsy, taken from lung mass, consisted solely of liver tissue. We confirmed diagnosis of Intrathoracic Accessory Lobe of Liver. In view of risk of malignant transformation, Serum Alpha Fetoprotein was done which was normal. As she is currently asymptomatic, she is planned to be kept on 6 monthly follow-up. Our case report is an extremely rare diagnosis, and highlights the need to keep normal anatomic aberrations in mind when evaluating a seemingly suspicious mass. Management depends on symptoms, anatomy of accessory lobe, and clinical and biochemical suspicion of underlying malignancy. Understanding of this rare condition is pivotal for prompt diagnosis of this infrequent condition and appropriate management and surveillance.