Mesenchymal hamartoma of the liver

Mesenchymal hamartoma of the liver demonstrating peripheral calcification in a 12-year-old boy

Mesenchymal hamartoma of the liver is a rare benign hepatic tumor that typically presents in the first 2 years of life. Approximately 85% of affected children present before the age of 3 years and less than 5% present after the age of 5 years. Although spontaneous regression has been reported in this benign tumor, most mesenchymal hamartomas gradually increase in size and can reach enormous proportions. We present an atypical case of mesenchymal hamartoma in a 12-year-old boy. The boy's age and presence of calcifications on CT demonstrate a unique presentation of this rare entity.

Difficulties in the management of mesenchymal hamartomas

AIM

Mesenchymal hamartoma of the liver is an entity with a varied presentation and frequent initial delay in diagnosis. The macroscopic appearance too is quite heterogeneous with solid, cystic and mixed variants being present with varying degrees of vascularity. Management will depend on presentation and expertise available. We look at a single centre experience with the mesenchymal hamartomas.

METHOD

Retrospective patient record review of the past 30 years, 1976-2006.

RESULTS

Seventeen patients aged 1 day to 15 years were identified, with a histopathological diagnosis of mesenchymal hamartoma of the liver. The anatomical location in the liver was 12 in the right liver and the 5 in the left. All patients presented with abdominal distension, eight had significant anorexia and or vomiting. Ultrasound scan was done in all patients. Findings were that of a mass and or cysts. The cysts were multiple in all cases but one and were interspersed with solid elements. Calcification was noted in only two of the patients. Operative approaches were six right hepatectomy, four wedge excision, seven tumour excisions by division of its pedicle; two of these were done laparoscopically, by cyst drainage and excision of the solid component. The tumours were all confirmed as mesenchymal hamartomas; size ranged from 412 to 2,230 g. Complications included three related to misdiagnosis (hydatid disease, and hepatoblastoma). Intraoperative problems consisted of preoperative bleeding resulting in an on-table hypovolaemic arrest and in a second case a bile duct injury. Postoperative problems consisted of an initial incomplete resection, with residual tumour on the IVC. There was rapid regrowth of tumour and death after a second exploration. Two children developed fluid collections requiring re-exploration and drainage. The surviving children have been followed up for a median time period of 4 months (range 1 month-11 years) and are well.

CONCLUSION

Although hamartomas of the liver are histologically benign, their clinical course and the complications of surgical treatment can be significant. They can often pose diagnostic dilemmas and may have a propensity for local recurrence and malignant degeneration.

Mesenchymal hamartoma of the liver: a systematic review

Mesenchymal hamartoma of the liver is the second commonest benign liver tumor in children, yet its biology and pathogenesis are poorly understood. Cytogenetic studies have suggested that the tumor may be a neoplasm rather than a hamartoma. Typically, it presents as a large benign multicystic liver mass in a child younger than 3 years amenable to complete resection. However, its imaging characteristics are variable, ranging from a few large cysts to a solid mass occupying one or both lobes of the liver. In addition, the tumor occasionally contains angiomatous elements or is multifocal. Most tumors gradually increase in size, some reaching enormous proportions, which can make surgery challenging. Paradoxically, a few undergo incomplete spontaneous regression and, on rare occasions, others have shown malignant transformation to undifferentiated (embryonal) sarcoma. These unusual pathological and biological features must be taken into account when considering the management of affected individuals.

Extrathoracic liver hamartoma

Mesenchymal hamartoma is a benign tumor of the liver that often presents because of a palpable abdominal mass or respiratory distress. An unusual protrusion of this tumor through the chest wall of a neonate with Poland's syndrome is reported.

Hepatic mesenchymal hamartoma in a neonate: a case report and review of the literature

To describe an unusual presentation of mesenchymal hamartoma in a critically ill neonate necessitating a novel therapeutic embolization before definitive resection. An unusual presentation of a large hepatic mass in a newborn complicated by pulmonary hypertension and vascular "steal" with renal insufficiency is presented. The mass was initially successfully embolized, but then revascularized, necessitating resection in an attempt to improve the clinical status of the critically ill neonate. The resected mass was a mesenchymal hamartoma with a necrotic center and extensive arterial collateralization. The patient began improving immediately after resection. Mesenchymal hamartoma may present in the neonate as a diagnostic dilemma. This is the first case report describing persistent pulmonary hypertension and renal compromise from this tumor. Embolization as a therapeutic modality to address this tumor is described. The cause of the persistent and severe pulmonary hypertension remains unclear,but may be related to the tumor.

New sonographic appearance of hepatic mesenchymal hamartoma in childhood

We present clinical, radiographic, and sonographic findings in 3 children with hepatic mesenchymal hamartoma, a rare benign tumor of childhood. The presence of round hyperechoic parietal nodules within the cystic spaces of the hamartomas is a new sonographic finding.

Conservative management of mesenchymal hamartoma of the liver

The natural history of mesenchymal hamartoma of the liver is poorly understood. This case demonstrates the course of a biopsy-proven mesenchymal hamartoma using sequential computed tomography (CT) examinations. These CT scans show initial expansion of the lesion with subsequent involution. The spontaneous resolution in this patient suggests the possibility of conservative management of asymptomatic mesenchymal hamartomas. The case is presented, and the literature on mesenchymal hamartoma is reviewed.

Cystic mesenchymal hamartoma of the liver

Two cases of multicystic mesenchymal hamartoma of the liver in children are described. In both cases noninvasive imaging techniques (ultrasound, CT or MR, radionuclide scan) showed a bulky cystic mass suggesting a correct preoperative diagnosis, while selective arteriography defined the operability of the tumor.

Benign liver tumors

This article discusses the most important benign liver tumors, both in adult and pediatric patients. A pathologic discussion of each neoplasm is included to provide a basis for understanding the radiologic-pathologic correlation that is used throughout the monograph. The benign liver tumors are presented according to their frequency. Therefore, hemangioma, the most common primary benign liver neoplasm, is discussed first, followed by focal nodular hyperplasia, hepatocellular adenoma, and the benign primary pediatric tumors--infantile hemangioendothelioma and mesenchymal hamartoma. Finally, a brief discussion of nodular regenerative hyperplasia and other rare hepatic masses is included. Bile duct cyst (simple, non-parasitic cyst of the liver) is not included since it is not a neoplasm. Likewise, cystadenoma is not discussed since it originates from the biliary duct cell and is appropriately included in the biliary neoplasms category.

Giant hamartoma of liver mimicking malignancy

Two infants with mesenchymal hamartoma of the liver are reported. This lesion clinically simulates a malignant neoplasm very closely and awareness is essential to avoid unnecessary major hepatic resections. The cases were successfully treated with simple enucleation.

Benign tumors of the liver in children: analysis of a series of 20 cases

Twenty children were treated for a benign hepatic tumor during a 17-year period. One child was not operated upon but followed since birth for 2 years by ultrasonogram. Mesenchymal hamartoma was found in 8 cases, a solitary cyst in 4, and 3 other cases of hamartomas were without cystic components. Two girls had lesions corresponding to focal nodular hyperplasia; two children had a solitary adenoma. Radical surgical treatment was possible in all 19 operated cases, except one case of focal nodular hyperplasia where a right lobectomy would have been necessary. Ultrasonography and angiography are the main explorations to be undertaken before treatment; preoperative embolization of the main arteries to the tumor was done in five cases, with unquestionable advantage in four of them. No mortality was recorded and results were good with a mean follow-up of 19 months.

Abdominal masses

The more common abdominal masses of the pediatric age group are discussed along with current thoughts regarding preoperative imaging modalities. A careful physical examination is indispensable, and masses should be evaluated with consideration given to mobility, location, consistency, contour, and site. A rectal examination is essential. The more unusual clinical presentations are discussed in appropriate sections.

Mesenchymal hamartoma of the liver responsive to cyclophosphamide therapy: therapeutic approach

A newborn infant is described with a highly vascular hepatic mesenchymal hamartoma causing hydrops fetalis, congestive heart failure, and consumption coagulopathy. There was a remarkable response of this life-threatening condition to cyclophosphamide therapy. A review of the various alternative therapeutic modalities is presented.

Perinatal (congenital and neonatal) neoplasms: a report of 110 cases

One hundred ten congenital and neonatal tumors encompassing a 25-year period are described and compared with similar published cases. Forty percent are classified as histologically malignant, and 65% of neonates with malignancies died. The types, frequency, and clinical features of neoplasms encountered in the perinatal period are markedly different from those observed in older children and adolescents. Their biological behavior and response to therapy are also dissimilar. Leukemia was responsible for the largest number of deaths followed by neuroblastoma and brain tumors.