Giant mesenchymal hamartoma in pediatric patients: A new indication for liver transplantation

Outcomes of Primary Tumor Excision do not Differ from Non-Resection Methods in Pediatric Mesenchymal Hamartoma of the Liver: A Rapid Systematic Review

BACKGROUND

To conduct a rapid systematic review comparing the outcomes of primary tumor resection versus non-resection on patients with hepatic mesenchymal hamartoma.

METHODS

We searched the Ovid MEDLINE, EMBASE, Scopus, PubMed, Web of Science, and Google Scholar databases from January 1, 2000 to March 31, 2022. Studies that described cases of hepatic mesenchymal hamartoma, including management and outcomes, were included.

RESULTS

62 articles met inclusion criteria with 95 cases in total. Patients were assigned to the primary tumor resection (n = 85) or non-resection (n = 10) cohort based on the described management. Similar rates of morbidity (17% vs 20%) and mortality (6 vs 10%) were identified between cohorts. There were no differences in sex, liver lobe involvement, or tumor size among study groups.

CONCLUSIONS

Complete tumor resection should remain the gold standard for hepatic mesenchymal hamartomas when an adequate liver remnant exists. Reports of non-resected tumors demonstrating spontaneous regression or stability with watchful waiting have poor long term follow-up and have inadequate evidence of a true mesenchymal hamartoma diagnosis.

LEVEL OF EVIDENCE

Level I.

Mesenchymal Hamartoma With Elevated Alpha-Fetoprotein: A Diagnostic Pitfall

Mesenchymal hamartoma (MH) is a benign liver tumor accounting for 3% to 8% of all liver tumors in children, commonly manifesting before 3 years of life. Distinguishing MH from hepatoblastoma and other liver tumors relies on imaging and alpha-fetoprotein (which is usually within normal range in MH), before histologic examination. We report a case of a hepatic MH associated with elevated alpha-fetoprotein, leading to a misdiagnosis of hepatoblastoma and the administration of chemotherapy. We draw the attention to the diagnostic difficulty and pitfalls related to alpha-fetoprotein elevation in the setting of a liver tumor, and we highlight the importance of imaging and histology in establishing the diagnosis.

Giant Mesenchymal Hepatic Hamartomas With Adrenal Involvement Precipitating Respiratory Failure: A Myxomatous Mystery in a Three-Month-Old

The combination of placental mesenchymal dysplasia and hepatic mesenchymal hamartomas is an extremely rare finding. We present the case of a three-month-old female born at 35 weeks gestation with a history of placental mesenchymal dysplasia who presented with non-bilious, non-bloody emesis, and episodes of respiratory distress due to multiple enlarging abdominal cystic lesions. The patient's presentation was unique due to both liver and adrenal solid and cystic lesions. After extensive imaging and multiple biopsies, expert interpretation of biopsy tissue revealed hepatic mesenchymal hamartoma within the liver and the adrenal gland. To our knowledge, this is one of the few documented cases of unresectable hepatic mesenchymal hamartomas with adrenal involvement successfully undergoing a whole liver transplant.

Fetal mesenchymal hamartoma of the liver: A case report and literature review

This paper reports the diagnosis and treatment process of a case of fetal mesenchymal hamartoma of the liver (MHL), and reviews the previous literature reports. At 38⁺² weeks of gestation, prenatal ultrasound found a well bound mixed solid and cystic mass, which was located at the lower edge of the right lobe of the liver and in front of the right kidney of the fetus, but the source and nature of the mass were not clear by ultrasound. Due to the approaching due date, the fetus showed no other abnormal symptoms, and no special treatment was given with the consent of the family members. A female fetus was delivered weighing 3,520 g at 39 weeks. An exploratory laparotomy was performed on the eighth day after delivery. During the operation, it was found that the tumor originated from the fifth, sixth and seventh hepatic segment and the corresponding hepatic segments were removed. Recovery was uneventful and the infant was discharged on the 6th day after surgery. Follow-up at 2 years showed a thriving young girl, and there was no tumor recurrence.

Infantile mesenchymal hamartoma of the liver with elevated alpha fetoprotein

Mesenchymal hamartoma of the liver (MHL) is a benign tumour that most commonly occurs in children. In most cases of MHL, the α fetoprotein (AFP) level is within the normal limits, only in a few cases, increased AFP has been described which usually causes misdiagnosis of hepatoblastoma. We report a case of a 3-month-old paediatric patient who was incidentally detected with a very high level of AFP, at 6388.4 ng ml⁻¹. Ultrasound revealed a right liver tumour, segment VI, measuring at 56 × 53 mm. According to images of ultrasound and MRI, the diagnosis was mesenchymal hepatic sarcoma. The paediatric patient had surgery to remove the entire liver segment containing the tumour. Micropathological examination showed that the tumour was a MHL. The serum AFP level fell rapidly to near normal following the surgery. The MHL benign liver tumour with an atypical presentation caused a very high AFP level. This was a rare clinical case, and it was difficult to diagnose.

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.

Hepatic mesenchymal hamartoma and undifferentiated embryonal sarcoma of the liver: a pathologic review

This review highlights two rare entities that are predominantly seen in children: hepatic mesenchymal hamartoma (HMH) and undifferentiated embryonal sarcoma of the liver (UESL). HMH is a benign lesion predominantly seen in the first 2 years of life, while UESL is malignant and usually identified in patients between 6 and 10 years of age. UESL may arise in the background of HMH, and the association has been supported by similar chromosomal aberrations (19q13.4). The diagnosis of both lesions is primarily based on histologic evaluation, as the clinical and radiological features are not always typical. The clinicopathologic characteristics, pathogenesis, differential diagnoses and treatment for both lesions are discussed.

Mesenchymal Hamartoma in Children: A Diagnostic Challenge

Mesenchymal hamartoma is a benign tumor of the liver with a poorly understood pathogenesis. It is uncommon in older children, especially after 2 years of age. The signs and symptoms may be nonspecific; therefore, a high index of suspicion is required for diagnosis and treatment. We report a 5-year-old previously healthy male who presented with acute abdominal pain, fatigue, and fever. He was diagnosed with pneumonia initially and treated with antibiotics. A computed tomography (CT) scan done for evaluation of his persistent abdominal pain demonstrated a hepatic mass. Follow-up magnetic resonance imaging (MRI) of the liver demonstrated multiple serpiginous tubular-type structures, read as possible Caroli syndrome. He had a normal abdominal examination and normal biochemistries including alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and alpha-fetoprotein. He was referred to our institution for second opinion. On further review of his imaging studies, the lesion was thought to be a mesenchymal hamartoma. He subsequently underwent resection of the mass. Pathology confirmed the diagnosis of mesenchymal hamartoma.