Mesenchymal hamartoma of the liver in infants

Renal and hepatic tumors in the neonatal period

Renal and hepatic tumors in neonates are extremely rare. Nevertheless it is important for clinicians to be familiar with them. Both renal and hepatic neonatal tumors are heterogeneous collections of several tumor types. Some renal and hepatic tumors are benign and may require no interventions whereas others can be associated with significant morbidity and even mortality and may require multimodality treatment. Early diagnosis and initiation of the proper treatment plan is crucial for achieving the best outcomes for these rare tumors in this vulnerable population.

Hepatic mesenchymal hamartoma in a preterm newborn: demonstration by low-dose multidetector CT

Primary liver tumours are very rare in the neonatal period. Differential diagnoses include haemangioendothelioma, malignant hepatoblastoma and mesenchymal hamartoma. Due to non-specific clinical symptoms and indecisive imaging findings, correct diagnosis may be difficult to establish. We report a female preterm newborn who was delivered at 33 weeks of gestation and in whom ultrasonography (US) revealed a large cystic intraabdominal tumour of unknown origin. For further evaluation, contrast-enhanced multidetector computed tomography (CT) was performed on the 4th day of life using a low-dose protocol (80 kVp, 50 mAs, collimation 0.75 mm, total effective dose 3.6 mSv). Based on CT findings, diagnosis of an intrahepatic mesenchymal hamartoma was made and confirmed by tumour resection and histopathological examination. In conclusion, multidetector CT (MDCT) using a low-dose protocol can be exceptionally used to establish diagnosis of a mesenchymal hamartoma in a preterm newborn.

Solid mesenchymal hamartoma in an adult: a case report

Mesenchymal hamartoma of the liver (MHL) is an uncommon tumour composed of architecturally abnormal bile ducts in an uncommitted myxoid stroma. Most MHL are diagnosed in childhood and few cases have been reported in adults. This report describes a case of a well defined solid mass in the right lobe of the liver in a 51 year old man. Preoperative radiological examination revealed a large completely solid mass. Biopsy showed a dense fibrous stroma with hyalinisation and some bile ducts. A provisional diagnosis of MHL was made. Surgical excision was impossible and liver transplantation was undertaken. Definitive pathology confirmed the diagnosis. Review of published reports shows this to be the fourth case of MHL treated by liver transplantation.

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.

Liver tumors in children

Primary hepatic neoplasms in children are relatively infrequent, accounting for between 0.5 and 2.0% of all pediatric neoplasms. They are a diverse group of epithelial and mesenchymal tumors whose incidence can vary considerably with patient age. They are clinically relevant tumors however as two thirds of them are malignant. The therapy of these tumors has evolved over time and it currently involves a combination of surgery, adjuvant and neoadjuvant chemotherapy and possible transplantation.

Fetal therapy for giant hepatic cysts

Cystic mesenchymal hamartoma is an extremely rare, benign tumor. Rapid growth to a giant size can pose a threat not only in early childhood but also during fetal life. The experience with 2 antenatally diagnosed giant hepatic cysts with widely disparate approaches to management, treatment, and outcome is presented. A giant hepatic cyst was diagnosed on routine screening ultrasound scan. Because of its extremely massive size, the cyst was treated in utero with repeated aspirations, primarily for obstetric considerations. The infant did well, and the lesion was excised laparoscopically during the neonatal period. A second fetus with a giant hepatic cyst was not treated in utero, and the pregnancy continued to term. Nonimmune hydrops fetalis developed, and the fetus was delivered prematurely at 34 weeks. At birth, the infant was noted to have diffuse neurologic injury and no urine output despite normal-appearing kidneys. The lesion was excised during the neonatal period by open laparotomy. Observations at the time of surgery and pathologic studies of the placenta showed aneurysmal dilatation of the placental veins suggesting in utero compression of the fetal intraabdominal umbilical vein. The infant died shortly after birth. The experience with these 2 cases suggests the possibility that giant mesenchymal hamartoma diagnosed in utero may cause umbilical venous obstruction leading to ischemia during fetal life. Decompression of giant hepatic cysts may reverse this phenomenon and allow normal fetal development.

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.

Mesenchymal hamartoma of the liver. DNA flow cytometric analysis of eight cases

BACKGROUND

Mesenchymal hamartoma of the liver is a rare lesion seen predominantly in childhood, which is believed to be either a developmental anomaly or reactive process. Because of recent reports of specific translocations involving chromosome 19 in mesenchymal hamartomas and certain ultrastructural and histologic features suggesting a relationship between mesenchymal hamartoma and undifferentiated (embryonal) sarcoma of the liver, some have speculated that mesenchymal hamartoma may be a neoplastic lesion with uncertain malignant potential.

METHODS

Because DNA aneuploidy can be useful as a marker for neoplasia, the authors decided to assess ploidy in paraffin embedded mesenchymal hamartomas using flow cytometry. The authors retrospectively examined mesenchymal hamartomas from eight children and evaluated the clinicopathologic features and the ploidy of the lesions.

RESULTS

Boys and girls were equally affected, and the mean age at presentation was 11 months. Lesions involved predominantly the right lobe of the liver, with a range of greatest dimension of 7-25 cm, and a mean weight of 651 g (though weights for three of the largest lesions were not recorded). Flow cytometric analysis of nuclei extracted from paraffin embedded tissue revealed that six of the eight lesions were DNA diploid, whereas two were DNA aneuploid (with DNA indices of 1.13 and 1.25). All of the lesions had a low S phase fraction.

CONCLUSIONS

The authors concluded that although most mesenchymal hamartomas are diploid, a subset of mesenchymal hamartomas is aneuploid. The finding of aneuploidy in mesenchymal hamartoma, in conjunction with the reported cytogenetic abnormalities, suggests that mesenchymal hamartoma may be a true neoplasm and not a developmental anomaly or reactive process.

Hepatic neoformations

The aim of the paper is an accurate histologic description and illustration of those liver lesions that are usually summarized under the heading of "hepatic tumors and related subjects". For in some cases it may be unclear or at least controversial, whether the individual lesion is indeed an autonomous neoplasia or a malformation, regeneration or hyperplasia, the indifferent master term of neoformation is introduced, based on the fact that all of them are characterized by a cellular multiplication. According to common definitory practice the survey distinguishes between mesenchymal (angiomatous and non angiomatous) and epithelial neoformations. Among the latter hepatocellular and cholangiocellular types are distinguished, the criterium for differentiation being a phenomenological one, which is by no means identical with a histogenetical statement. The definition of subgroups mostly adheres to current nomenclatory usage; only occasionally--in the group of endothelial tumors--a novel term is employed, in view of brevity and coordination with the overall system of neoformations.

Ultrasonographic diagnosis of a fetal abdominal mass: a case of a mesenchymal liver hamartoma and a review of the literature

A case of a prenatally recognized hepatic mesenchymal hamartoma is presented and the literature reviewed. These tumors are benign and usually present in early infancy with symptoms that are related to the mass effect on adjacent organs. Radiologic methods used in the past to image this tumor include angiography and ultrasound. However, there is no specific radiologic finding, and, therefore, the diagnosis is usually made during surgery. Once the tumor is removed, the prognosis is generally good. With the increasing use of high resolution ultrasound in prenatal diagnosis, this rare tumor should be considered in the differential diagnosis of any multicystic mass found in the fetal abdomen. The recognition of a mass should then alert the physician to the need for early neonatal intervention.

Immunohistochemical and electron microscopic findings in a case of mixed hamartoma of the liver

A case of mixed hamartoma of the liver in a 36 day old female infant is reported herein. The resected tumor was well demarcated, measured 7.5 X 7.0 cm and weighed 179 gm. Microscopically, the tumor was composed of loose fibrous stroma intermingled with spindle and polygonal cells and ductular structures. The spindle and polygonal tumor cells displayed the distinct cytoplasmic staining for alpha-1-antitrypsin. Most of the tumor cells showed the characteristic ultrastructural features of immature hepatocytes, having numerous cytoplasmic microvillous structures, abundant rough and smooth endoplasmic reticulum and mitochondria. These findings suggest that embryonic liver cells, which are capable of transforming into biliary structures and hepatocytes, serve as essential elements of mixed hamartoma of the liver.

Cytogenetic analysis of a mesenchymal hamartoma of the liver

Cytogenetic analysis of a mesenchymal hamartoma of the liver in a 3-year-old child revealed a balanced translocation between chromosomes 15 and 19 as the sole chromosome change.

Mesenchymal hamartoma of the liver in an adult: radiologic diagnosis

A case of mesenchymal hamartoma of the liver in a 30-year-old female is reported. Ultrasonography, computed tomography, and hepatic angiography demonstrated the presence of a large, mixed cystic and solid mass within the liver, suggesting the diagnosis of a mesenchymal hamartoma. At surgery, the tumor proved to be unresectable.

An unusual case of solid hamartoma in the liver

An unusual case of solid hepatic hamartoma, which could not be correctly categorized under the WHO classification, is reported. The well defined, solid nodular lesion, arising in the anterior edge of the left hepatic lobe, was found in a 15-month-old female infant. The lesion was composed of irregularly shaped yellow islands of parenchyma and white-gray nodules of fibrous stroma of various sizes, which were intermingled revealing a mosaic pattern. Prominent bile ductal proliferation was observed histologically in the fibrous stroma, associated in parts with dense or loose periductal bundles and vascular proliferation. The stromal proliferation seemed to result in erosion of the islands of differentiated parenchymal cells with no regeneration. Alpha-fetoprotein was demonstrated immunohistologically in the parenchymal cells of the lesion. From these findings, the essential component of this solid hamartoma was thought to be markedly proliferating bile ducts associated with periductal fibrosis, resulting in a fibroadenomatous pattern.

Angiography for abdominal pediatric tumors

Angiography is an important investigative device in the diagnosis and staging of liver tumors. With Wilms' tumors that are bilateral, or if there is suspected inferior vena caval involvement, angiography is helpful. Therapeutic embolization can be very effective with hepatic hemangiomas and certain Wilms' tumors.

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.

Mesenchymal hamartoma of the liver in an older child: association with disseminated intravascular coagulation

A 9-year-old black girl underwent right hepatectomy because of a large primary tumor in the right lobe of the liver. Histopathologic examination revealed the diagnosis of mesenchymal hamartoma, a rare benign tumor occurring mostly in children below the age of 2 years. Preoperatively, the patient had laboratory evidence of mild disseminated intravascular coagulation (DIC) but had no bleeding manifestations. In preparation for the surgery, the patient received whole blood exchange transfusion and platelet transfusion which re-resulted in marked improvement in hemostatic parameters. Despite what appeared to be adequate replacement of blood loss during the surgical procedure, the patient developed sudden cardiac arrest near the end of the procedure and died. The probable cause of death was hypovolemia. This case of mesenchymal hepatic hamartoma illustrates two unusual features: age of the patient and the association with DIC. The latter, to our knowledge, has not been reported before.

Mesenchymal hamartoma of the liver

Mesenchymal hamartoma is a benign, cystic lesion that arises from connective tissues of the portal tracts. It is most common in children under 5 years of age. The diagnosis can be suspected when a relatively asymptomatic child has a large, smooth mass in the liver. Radionuclide scans demonstrate a solitary lesion, and on ultrasound there are cystic spaces and septa. These are perfectly benign lesions and may be simply enucleated.

Undifferentiated ("embryonal") sarcoma of the liver: ultrastructure of a case presenting as a primary intracardiac tumor

We report the ultrastructure of an undifferentiated ("embryonal") sarcoma of the liver that presented as a right-sided intracardiac tumor in an 8-year-old boy. The patient eventually died because of repeated embolization of tumor to the lungs. At autopsy the hepatic primary was composed of primitive mesenchymal cells with occasional small cysts and ducts lined by benign-appearing epithelium. Electron microscopy of the mesenchymal cells indicated a limited capacity for pluripotential differentiation along fibroblastic, lipoblastic, and even myogenous lines. Epithelial elements closely resembled those lining normal bile ducts but contained increased fibrillar material with haphazard orientation. The histogenesis of this rare hepatic tumor is still unknown, but the occurrence of both epithelial and frankly sarcomatous elements within the primary tumor again raises the possibility of malignant transformation within a pre-existing mesenchymal hamartoma.

Mesenchymal hamartoma of the liver: report of 30 cases and review of the literature

Thirty cases of mesenchymal hamartoma of the liver are presented and compared with 42 previously published cases. The patients, 69% male, range in age from newborn to 10 years (average age 15 months, median age 10 months). Except for occasional cases in which the lesion is an incidental finding at autopsy, most present with progressive abdominal enlargement over a period of days to months. Physical and radiologic examinations are nonspecific except for the demonstration of a mass within or attached to the liver. The masses are large, averaging 1311 g, and frequently contain cysts filled with clear fluid or gelatinous material. Histologic examination shows a mixture of loose mesenchymal tissue, bile ducts, connective tissue, and hepatocytes along with cysts formed either from degenerative areas of mesenchyme or from dilated bile ducts and lympathics. Treatment is partial or total excision of the lesion. Mortality (7-17%) is related to intraoperative or postoperative complications. Recurrence or malignant transformation has not been noted.

Primary hepatic tumors of childhood

A clinicopathologic review of 73 cases of primary liver tumors at Texas Children's Hospital, Houston, and Children's Medical Center, Dallas, has documented important prognostic and therapeutic implications for the histologic classification of hepatoblastoma. The pure "fetal" pattern was associated with cure in every instance that surgical excision was achieved (six of six patients), whereas only two of 19 patients with "embryonal" or other undifferentiated patterns of growth survived five years. The relationship of hepatoblastoma and hepatocarcinoma in childhood to antecedent conditions is discussed in detail. The uncommon liver sarcomas are also reviewed in the light of experience at these two institutions.

Multicystic hepatic mesenchymal hamartoma of childhood. Computerized tomography and ultrasound characteristics

A case of massive mesenchymal hamartoma of the liver is described in a 13-month-old infant. A complex multicystic mass was demonstrated by ultrasound and computed tomography (CT). The appearances suggested the preoperative diagnosis.