The occurrence of HMH is a rare event even though it is the second most benign hepatic tumor of childhood [4]. Hamartoma is an overgrowth of tissues, indigenous to the site. Histologically HMH consists of a mixture of cysts, bile ducts, hepatocytes, and mesenchyme [4].

Neonatal hepatic mesenchymal hamartoma (HMH) usually presents as an asymptomatic mass which is detected incidentally on ultrasound. It can also present with symptoms like abdominal distention, pain and respiratory distress. Other features include cardiac failure, anorexia, vomiting, poor weight gain, vascular steal and thrombocytopenia, intralesional bleeding, pulmonary hypertension, tumor rupture, ascites, pedal edema, obstructive jaundice, and smooth, and large non-tender hepatomegaly [8].

The differential diagnosis of HMH could be any abdominal cystic lesion in a newborn like mesenteric cyst, duplication cyst, hepatoblastoma, teratoma, lymphangioma, choledochal cyst, and renal cyst [8]. These could all be differentiated from HMH using imaging studies.

The initial investigation is plain X‐ray abdomen. It may show calcification or soft tissues mass with displacement of bowel [8]. Ultrasound, computed tomography, and magnetic resonance imaging of HMH may show a multiloculated cystic tumor with varying amounts of solid components. With ultrasound scan, the presence of thin mobile septae and round hyper-echoic parietal nodules within the cyst is highly suggestive of HMH.

Cases of HMH presenting with jaundice are rare but described earlier in the literature. These were predominantly cases of obstructive jaundice as a result of biliary tract compression by the mass. In 1982 Henrik Ehren et al. published a series of 48 cases of benign liver tumors in infancy. The author described a newborn girl who was admitted to the hospital with hepatomegaly and jaundice. The reason for jaundice was found to be a hamartoma partially obstructing the extrahepatic bile ducts [9]. Heller. K et al. in 1992, described another case concerning a 2-year-old female child, who was found to have a hamartoma of the liver located centrally in the hilar region. She presented with severe biliary obstruction which developed rapidly and was surgically treated [10].

Our patient presented as a case of neonatal jaundice (indirect hyperbilirubinemia). This can be explained by the hemorrhage into the tumor causing heme catabolism leading to excess bilirubin production.

Cases of HMH with indirect hyperbilirubinemia are much rarer when compared to direct hyperbilirubinemia. A case of a 3-week-old male newborn with HMH and mild indirect hyperbilirubinemia was described by Moaied A. Hassan in 2020. But the presenting complaint was not jaundice but abdominal distension and respiratory distress [11].

Treatment options include enucleation of small lesions or marsupialisation into the peritoneal cavity in case of large lesions. However, the gold standard of treatment is complete surgical excision with a margin of normal tissue of the liver. This is to avoid local recurrence and long-term malignant transformation [11]. In our case, we did a near total excision with marsupialisation. Complete excision was not feasible as it was in close relation with hepatic vasculature.