Giant solid mesenchymal hamartoma of the liver in a neonate: case report

Background: Mesenchymal hamartoma is the second most common benign liver tumor in children, with 20% of the cases diagnosed during the neonatal period. The exact etiology in still unclear, and most investigators believe that it is a developmental anomaly rather than a true neoplasm. The presentation of these tumors is highly variable depending on the lesion's size, ranging from small asymptomatic lesions to very large tumors with life threatening complications. Radical surgical excision, whenever possible, is the gold standard for treating these lesions to avoid the problems of local recurrence and possible malignant transformation. We present the rare occurrence of an entirely solid, giant hepatic mesenchymal hamartoma in a 3-week-old male newborn and discuss the mode of presentation, as well as the diagnostic and therapeutic approach. Case presentation: A 3-week-old male newborn was referred to our institution with huge abdominal distension and respiratory distress. Imaging studies confirmed the presence of a very large solid intraabdominal mass occupying the majority of the abdominal cavity and abutting the inferior aspect of the right lobe of the liver, but did not reveal the diagnosis. At laparotomy, a huge solid mass was found attached to the right lobe of the liver. Complete excision was done, and histopathological examination confirmed the diagnosis of mesenchymal hamartoma. Conclusion: Although rare, mesenchymal hamartoma of the liver can present as a neonatal surgical emergency. Emergency intervention is required in symptomatic patients. Radical surgical intervention is possible and is the treatment of choice to relieve the patient's symptoms and avoid future complications.