Conservative management of mesenchymal hamartoma of the liver

Mesenchymal hepatic hamartoma: A rare case of severe respiratory distress in a neonate

It is critical to consider intra-abdominal pathology in cases of neonatal respiratory distress. Accurate and prompt diagnosis via computed tomography is lifesaving. We have highlighted the effectiveness of rapid surgical intervention as curative.

Progression of a persisting mesenchymal hamartoma to intrahepatic cholangiocarcinoma 24 years after the initial diagnosis: A case report

Mesenchymal hamartoma of the liver (MHL) is a rare benign tumor that often presents in early childhood, and it rarely occurs in adulthood. Aberrant development of the portal tract is a known cause of MHL. Although limited information is available on the natural course of MHL, malignant transformation has been reported in a few cases. Here, we report a case of a 26-year-old female with intrahepatic cholangiocarcinoma secondary to unresected MHL. The patient underwent resection of the hepatic mass, which was diagnosed as MHL at 2 years of age, due to an increase in mass size and a suspicion of malignant transformation during work-up. Histopathology confirmed intrahepatic adenosquamous carcinoma in the background of MHL, with a T2N0M0 pathological stage (stage II). The surgical margin was free from tumor cells. The patient fully recovered postoperatively and started receiving adjuvant chemotherapy. Previous case reports have only reported about the development of undifferentiated embryonal sarcoma or angiosarcoma as malignant transformation of MHL. Cases of other malignancies have not been published; however, it is difficult to rule out the occurrence of various malignancies related to the portal tract when considering the pathogenesis of the disease. To the best of our knowledge, this is the first case report of adenocarcinoma of bile duct origin secondary to MHL. This case report suggests that aggressive surgical management should be considered after the initial diagnosis of MHL.

Mesenchymal hamartoma and undifferentiated embryonal sarcoma: diagnostic keys that radiologists need to know

OBJECTIVE

Hepatic tumors are uncommon in pediatric patients. Among the most common of these uncommon tumors are mesenchymal hamartoma and undifferentiated embryonal sarcoma, which have different origins but similar appearance on imaging studies. This paper reviews the characteristic findings and differential diagnosis of these entities. Ultrasonography is the first-line imaging test to study these tumors. Magnetic resonance imaging and computed tomography are useful for further characterizing the tumors and planning surgery.

CONCLUSION

Radiologists need to be familiar with the imaging findings of the different disease entities and to evaluate them together with the patient's age, personal history, and bloodwork.

Pediatric Liver Tumors

Although liver tumors are rare in the pediatric population, they are common in the setting of children with specific risk factors requiring increased awareness and, in some instances, screening. The evaluation of a liver mass in children is largely driven by the age at diagnosis, the presence of any medical comorbidities, and initial testing with alpha fetoprotein and imaging. Specific guidelines for the management of different tumors have been implemented in recent years such that a multidisciplinary approach is ideal and care should be provided by centers with experience in their management.

Mesenchymal Hamartoma of the Liver: Complete Excision Always Necessary

Mesenchymal hamartoma (MH) is not an uncommon tumor of the liver in the age group of 2-10 years. It is the second most common benign liver tumor in children. Previously considered a developmental anomaly, newer insights into other theories of origin including toxic-metabolic, ischemic, and a true neoplastic process are in progress. Previous understanding of a purely benign nature of the tumor is being overridden by a real malignant transformation. Complete excision of the tumor with clear margins is recommended to achieve a long term cure. A thorough understanding of the natural history of these tumors and skillful surgical treatment are indispensable elements of care.

Pediatric Mesenchymal Hamartomas of the Liver can Show Both Foregut and Hindgut Phenotype

Cystic epithelium in mesenchymal hamartoma (MH) is typically biliary type. Mucinous differentiation of the epithelium and increased hepatocellular component may pose a diagnostic challenge. We studied MH in 7 children (6 M, 1 F; age 4 months to 8 years, median 1 year). Resected tumors varied from 3.0 to 17.0 cm. All tumors showed biliary epithelium in the cystic component with strong and diffuse reactivity for CK7 and CK19. Expression of CK20 and CDX2 was additionally seen in 2 tumors, rare/focal in 1, and diffuse with mucinous differentiation in the other. Strong and continuous nuclear reactivity for Sox9 was seen in the cyst epithelium in all 7 tumors including focal staining in mucinous areas. It was also positive in the hepatocellular component. CD56 and vimentin were variably positive in the cystic epithelium of all cases. Alpha-fetoprotein showed patchy weak staining in the hepatocellular component and was negative in the cystic epithelium. Hepar-1 showed focal staining in the cystic epithelium in 4/7 cases and diffuse in the hepatocellular component. Both patients showing CK20 and CDX2 expression had abnormal chromosomal analysis: one with balanced translocation between chromosomes 2 and 19 and other with loss of chromosome Y. Among others, one showed 46,XY,inv(9)(p11q12), one did not grow cells, and the remaining 3 had normal karyotype. Six patients underwent resection and one had liver transplantation. All were alive and well with a median follow-up of 1.5 years. In conclusion, mucinous epithelium can be seen in MH. Expression of Sox9 in the cyst epithelium and hepatocytes suggests a common origin for these components. Expression of vimentin indicates an overlapping epithelial-mesenchymal phenotype. Hepatic MH can show divergent epithelial differentiation including both foregut and hindgut phenotype, which may provide insights into the pathogenesis of this rare neoplasm but does not seem to affect the outcome in this limited series.

Mesenchymal hamartoma or embryonal sarcoma of the liver in childhood: a difficult diagnosis before complete surgical excision

BACKGROUND

Clinical experience shows that the primary diagnosis of mesenchymal hamartoma (MHL) and embryonal sarcoma of the liver (ESL) recurrently is mistaken, leading to inadequate managements. We evaluated the accuracy of the primary diagnosis of those liver tumors, compared with the final histological diagnosis.

METHODS

Records of 25 children (0-16 years, treated 01/1989-01/2013) with final diagnosis of MHL or ESL were analyzed.

RESULTS

Final diagnosis was MHL in 18/25 children (10 solid-cystic, 2 cystic, 6 solid) and ESL in 7/25 (4 solid-cystic, 1 cystic, 2 solid). Only 3/7 ESL patients and 15/18 MHL patients fell into the "typical" age group. In 13/25 children primary diagnosis was based on imaging only. Overall, primary diagnosis was concordant with the final diagnosis in 17/25 patients. Of 99/25 biopsied cases, 4/9 biopsy results exposed the wrong final diagnosis; of cystic-solid masses 4/14 were mistaken, of cystic masses 1/3, of solid masses 3/8.

CONCLUSION

Preoperative diagnosis of MHL and ESL is challenging because of atypical clinical presentation, misleading "typical" radiological findings, and difficult interpretation of biopsies. If feasible, complete surgical resection of, in particular, solid-cystic liver masses in the pediatric age group must be aimed for, to get a definitive, final diagnosis, followed by an adequate treatment strategy.

Mesenchymal hamartoma of the liver--a case report and literature review

We report a case of a mesenchymal hamartoma of the liver in a two-year-old boy. He presented to the emergency room with abdominal distention and vomiting. Abdominal ultrasound and computed tomography were performed and revealed a large, intra-peritoneal lesion, with thick wall, multiple cysts of variable size and solid septa. The lesion was surgically resected. Pathological examination revealed a mesenchymal hamartoma of the liver. We are including a short literature review, highlighting the main features of mesenchymal hamartoma of the liver, and discussing its differential diagnosis.

Regression of mesenchymal hamartoma of the liver with sarcoma chemotherapy

We present a young patient with metastatic Ewing sarcoma that had hepatic lesions. As we were unaware of hepatic metastases in Ewing sarcoma, liver biopsy was performed. The pathologic findings were diagnostic of mesenchymal hamartoma of the liver. Surprisingly, the combined chemotherapy for metastatic sarcoma resulted in almost complete resolution of the hamartoma in the liver. This option may be useful in extreme cases when resection is not feasible.

Current concepts in pediatric liver tumors

Liver tumors in children can be classified into benign or malignant; some of the benign lesions can have the potential of malignant transformation, and therefore the therapeutic approach may change. These neoplasms account for nearly 1-2% of all pediatric tumors and they have gained significant attention in the last decades due to data suggesting that the incidence may be increasing 5% annually. We know that with new and improved imaging modalities some of these lesions may be detected more often than before. Recent studies showed that liver cancer represented 2% of malignancies in infants by 1980s and this was doubled in incidence to 4% in the following 10 yr. In this review our aim is to discuss all primary liver tumors in children with attention to their clinicopathological and immunohistochemical features followed by the current standard of care.

Multiple hepatic mesenchymal hamartomas in a premature associated with placental mesenchymal dysplasia

Placental mesenchymal dysplasia (PMD) is an uncommon disorder that has to be differentiated histologically from a partial mole. In contrast to a hydatitiform mole, PMD can coexist with a viable fetus. Placental mesenchymal dysplasia is characterized by placentomegaly and dilatation of the chorionic vessels. In our case, multiple hepatic mesenchymal hamartomas in a preterm were associated with PMD. This association is an extremely rare anomaly. Mesenchymal hamartomas occur in 5% of all primary liver tumors in children and are generally benign lesions.

[Cystic mesenchimal hamartoma of the liver in two-year-old patient--case report]

Mesenchymal hamartoma is an uncommon benign hepatic tumor arising from the mesenchyme of the portal triad. This lesion is relatively uncommon, representing 5% of all primary hepatic pediatric tumors. This form of hamartoma usually presents before the age of 2 years, typically with abdominal swelling as the initial symptom. The classic management of these lesions has been excision either by hepatic lobectomy or wedge resection. We present a case of 2-year-old girl with a right hepatic lobe tumor, 66 x 57 x 71 in diameter that was completely removed by right hepatic lobectomy.

Fetal and neonatal liver tumours

Liver tumours are rare in children and account for about 5% of all tumours in the fetus and newborn. The most frequently occurring are benign vascular tumours and mesenchymal hamartomas although malignancy in the form of hepatoblastoma is a possibility. While the diagnosis can be suspected antenatally (by ultrasound and MR scan), a precise diagnosis is often difficult due to the complexity of the tumours. Inutero development of such tumours may be associated with polyhydramnios, fetal hydrops and extreme cases the maternal mirror syndrome. Postnatal symptoms may include abdominal distension, cardiac failure, consumptive coagulopathy and bleeding due to tumour rupture, but is dependent on the nature of the actual tumour. Treatment options may include watchful waiting, surgical resection, hepatic artery embolisation/ligation and chemotherapy.

From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation part 1. Benign tumors

Benign hepatic tumors in children include lesions that are unique to the pediatric age group and others that are more common in adults. Infantile hemangioendothelioma, or infantile hepatic hemangioma, is a benign vascular tumor that may cause serious clinical complications. It is composed of vascular channels lined by endothelial cells. At imaging, large feeding arteries and draining veins and early, intense, peripheral nodular enhancement with centripetal filling on delayed images are characteristic features. Mesenchymal hamartoma of the liver occurs in young children and is characterized pathologically by mesenchymal proliferation with fluid-containing cysts of varying size and number. The mesenchymal component or cystic component may predominate; this predominance determines the imaging appearance of the tumor. Benign epithelial tumors that are common in adults may infrequently occur in childhood. These include focal nodular hyperplasia (FNH), hepatocellular adenoma, and nodular regenerative hyperplasia. All are composed of hyperplastic hepatocytes similar to surrounding liver parenchyma and may be difficult to discern at imaging. Preferential hepatic arterial phase enhancement helps distinguish FNH and hepatic adenoma from uninvolved liver. Hepatic adenoma often has intracellular fat and a propensity for intratumoral hemorrhage, neither of which are seen in FNH. Unlike adenoma, FNH often contains enough Kupffer cells to show uptake at sulfur colloid scintigraphy. Nodular regenerative hyperplasia is often associated with portal hypertension, which may be evident at imaging. Knowledge of how the pathologic features of these tumors affect their imaging appearances helps radiologists offer an appropriate differential diagnosis and management plan.

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.

Stromal-predominant mesenchymal hamartoma of the liver with elevated serum alpha-fetoprotein level

Mesenchymal hamartoma of the liver (MHL) is an uncommon, benign, tumor-like lesion and is usually diagnosed in the first 2 years of life. Its pathogenesis remains unclear. Treatment of choice is radical excision. The authors report a case of solid stromal predominant MHL in a 12-month-old male infant who also had an elevated serum alpha-fetoprotein level. He also had hypospadias, which might represent a spectrum of developmental anomalies. It usually presents as an asymptomatic mass, however, as in the reported case, it may cause several complications due to the compression of surrounding structures. He was successfully treated with total excision of the pedunculated large tumor without any complication.

Mesenchymal hamartoma of the liver accompanied by a daughter nodule: report of a case

Mesenchymal hamartoma of the liver (MHL) is an uncommon benign tumor found primarily in children younger than 2 years of age. We report a rare case of MHL with a daughter nodule and atypical histological findings in a 14-month-old girl. On admission, computed tomography, magnetic resonance imaging, and angiography showed a solid hypovascular mass with a central cystic area in the liver. Laparotomy revealed a tumor, 8 cm in size, occupying segment 5 and parts of segments 4 and 6 of the liver, and a small nodule, 10 mm in size, in segment 7. Thus, we performed a partial hepatic resection (S4-6) and tumor extirpation (S7). The histological findings of both tumors were the same, but atypical of MHL. Recent studies on the pathogenesis of this tumor have found neoplastic features such as genetic anomalies and malignant transformation. These findings suggest that the conventional approach of completely resecting the tumor whenever possible is the best treatment.

Tumors of the liver in children

In this review we examine the diagnosis and treatment of pediatric liver tumors- both malignant and benign. The two most common malignant tumors are hepatoblastoma and hepatocellular carcinoma. Hepatoblastoma is seen in younger children, hepatocellular carcinoma in older children. Other malignant liver tumors are quite rare and include biliary rhabdomyosarcoma, angiosarcoma, rhabdoid tumor, and undifferentiated sarcoma. The commonly seen benign liver tumors in children are infantile hemangioma, mesenchymal hamartoma, and focal nodular hyperplasia. Rare benign tumors are hepatic adenoma, which is occasionally seen in teenage girls, and teratoma which is a very rare liver tumor in infants.

Laparoscopic resection of a benign liver tumor in a child

Laparoscopy for the resection of liver masses in children has remained undeveloped despite the wide acceptance of laparoscopy in the field of pediatric surgery. The authors report a case of nonanatomical laparoscopic hepatic resection of a large mesenchymal hamartoma in a 2-year-old boy. The procedure was performed using an innovative approach with a combination of different technologies that allowed for a safe and precise resection. This case demonstrates the feasibility of a nonanatomical laparoscopic hepatic resection, even for very large tumors. Both technical expertise and use of novel technologies are necessary to ensure a precise and controlled resection.

Natural history and long-term follow-up of antenatally detected liver cysts

BACKGROUND/PURPOSE

Antenatally detected liver cysts are rare; their diagnostic accuracy is unknown, and their management is controversial. This study assessed the natural history of these lesions.

METHODS

We conducted a retrospective review of infants with isolated intrahepatic cysts that were detected antenatally. Data are expressed as median (range).

RESULTS

Fifteen infants presented during the period 1991-2004 with an antenatally detected liver cyst. Their gestational age at detection was 22 (18-34) weeks, and the maximum diameter of their cyst was 23 (10-120) mm. Serial scans, which were performed in 9 fetuses, showed cyst enlargement in 5 cases, diminution in 1 case, and no change in 3 cases. In utero percutaneous aspiration was required in 1 infant. Three infants underwent postnatal surgery. One fetus (postfetal intervention) had a subtotal excision of a large subcapsular cyst filling the abdominal cavity on day 2. Another infant required partial excision and marsupialization (complex cyst arising from segment IV) at 5 months, and a third infant underwent a cyst cholecystostomy at 4 months. Postnatal investigations (including hepatic scintigraphy) suggested that the remaining lesions were either simple parenchymal (n = 10) or isolated intrahepatic choledochal (ie, type V; n = 2) cysts. The median follow-up for these patients was 44 (27-167) months. Serial postnatal ultrasonography showed cyst diminution in 4 cases, an enlargement in 1 case, and no dimensional change in 7 cases.

CONCLUSIONS

Most antenatally detected liver cysts appear to be simple and of parenchymal origin and do not require fetal intervention. Their postnatal history is variable, but regression without treatment is seen in most cases.

Hepatic Mesenchymal Hamartoma: A Short Review

Hepatic mesenchymal hamartoma is a hamartomatous growth of mesenchymal tissue in the liver of uncertain etiology. It is a space-occupying lesion that can potentially compress adjacent organs resulting in various complications including death. Hepatic mesenchymal hamartoma is characterized by proliferation of variably myxomatous mesenchyme and malformed bile ducts. The differential diagnosis includes other pediatric hepatic masses. The diagnosis is typically made during infancy, and complete resection is invariably curative.

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.

Hepatic mesenchymal hamartoma mimicking hemangioma on multiple-phase gadolinium-enhanced MRI

Mesenchymal Hamartoma [MH] is a cystic benign liver mass occurring in children. Diagnostic confusion with hepatoblastoma may arise when alpha-feto-protein is elevated, and with hemangioendothelioma when imaging shows centripetal filling. We demonstrate one such case with progressive centripetal enhancement of a liver mass with Gadolinium enhanced multiple phase gradient-echo MRI, in a child with raised alpha-feto protein.

Laparoscopic fenestration of a neonatally detected hepatic mesenchymal hamartoma

We report a case of hepatic mesenchymal hamartoma that was detected neonatally and successfully treated by laparoscopic fenestration. A baby girl was referred to our hospital 9 days after birth with a cystic lesion in her liver. Screening abdominal ultrasonography revealed a sonolucent lesion measuring 65x43x40 mm in the right lobe of the liver with a small solid area. Magnetic resonance imaging depicted the lesion as hyperintense on both T1- and T2-weighted images with no enhancement. A laparoscopic biopsy and fenestration of the lesion was performed. Histologic examination of the cyst wall led to a diagnosis of hepatic mesenchymal hamartoma. The postoperative course was uneventful and the patient is doing well at 4 years' follow-up, with no recurrence.

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.

Congenital hepatic mesenchymal hamartoma associated with mesenchymal stem villous hyperplasia of the placenta: case report

A newborn with an unusual association of hepatic mesenchymal hamartoma and mesenchymal stem villous hyperplasia of the placenta is presented. At birth, the large hepatic mass caused severe respiratory distress necessitating early surgical intervention. This report on the association of hepatic mesenchymal hamartoma and mesenchymal stem villous hyperplasia of the placenta strongly suggests a common pathogenetic origin of the 2 lesions.

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.

Neonatal liver tumours

Primary liver tumours are very rare during the neonatal period, but increasing numbers of them are now diagnosed prenatally by routine ultrasound scan. A precise diagnosis is sometimes problematic because of non-specific clinical symptoms, misleading imaging and difficulties with histological interpretation. Benign infantile haemangioendothelioma usually undergoes spontaneous regression, but may be life-threatening due to congestive heart failure and/or consumptive coagulopathy when treatment with resection, embolization or arterial ligation is necessary. Malignant hepatoblastoma may occur in the newborn, and often has to be treated with chemotherapy to achieve resectability. Symptoms are less specific and the prognosis is worse than in older children. Mesenchymal hamartoma is a benign cystic lesion that should be resected whenever possible. Rarely, germ cell tumours occur in the neonatal liver. Benign teratomas have to be resected, while malignant choriocarcinomas may respond to chemotherapy and can be cured in some cases.

Hepatic mesenchymal hamartoma

Hepatic mesenchymal hamartoma (HMH) is a rare liver tumour in childhood. It is believed to be a benign tumour with a good prognosis if the tumour is excised. Only a few cases with local relapse or metastasis have been reported. We reviewed 134 patients with space-occupying liver lesions, from January 1990 to December 1999, and four patients with HMH were found. Abdominal mass and/or distension were the common initial presentations. Three of our four cases were diagnosed in the first year of life. The liver function tests and tumour markers were non-specific. Case 1 underwent tumour enucleation and another three cases underwent tumour excision. One patient died. No tumour recurrence was noted in the surviving patients.

Chromosomal translocation in mesenchymal hamartoma of liver: what is its significance?

Mesenchymal hamartoma of the liver is generally considered to be benign in nature, and surgical excision has been the treatment of choice. There have been 3 reports on the association of cytogenetic abnormalities with this tumor, and the possibility of malignant potential has been raised. The authors report a fourth case with a previously unreported complex chromosomal translocation between chromosomes 11, 17, and 19 at bands q12, p11, and q13.3, respectively in all cells examined and discuss the significance of this finding.

Fetal mesenchymal hamartoma of the liver: report of a case

The authors report a case of hepatic mesenchymal hamartoma diagnosed prenatally with ultrasound scan and magnetic resonance imaging (MRI) and confirmed histologically postdelivery. The fetus had a multicystic mass in the left upper abdomen, which showed a rapid enlargement accompanying maternal hypertension and preterm labor. The patient was delivered by cesarian section at 30 weeks and 5 days weighing 1,190 g, and, at birth, a large abdominal mass and severe anemia were noted. Surgical resection and neonatal management were successful, and the patient is alive in a good condition after 3 years follow-up. Although histologically benign, because this lesion frequently results in perinatal complications such as fetal hydrops, maternal toxemia, and preterm labor, early careful fetal ultrasonography should improve the prognosis of this lesion.

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.

Hepatic tumors in children

Although they account for only 1% to 4% of solid tumors in children, hepatic tumors and pseudotumors offer a diagnostic challenge to the clinician seeing only an occasional case. Metastatic lesions such as neuroblastoma, Wilms' tumor, and lymphoma are the most common neoplasm seen in the liver, but 10 distinct primary tumors and pseudotumors of the liver occur with some regularity, and a few others may be seen rarely, including leiomyosarcoma, rhabdoid tumor, and endodermal sinus tumor. Five of these neoplasms--hepatoblastoma, infantile hemangio-endothelioma, mesenchymal hamartoma, undifferentiated embryonal sarcoma, and embryonal rhabdomyosarcoma of the biliary tree--occur only in children and are the major focus of the article.

Benign liver and biliary tract masses in infants and toddlers

There is a remarkable diversity of conditions encompassed by benign liver masses in infants and toddlers. The most common benign hepatic tumor in this age group is infantile hepatic hemangioendothelioma. Other commonly seen benign tumors are mesenchymal hamartoma and focal nodular hyperplasia. Hepatic adenoma is almost exclusively a disease of older children; primary hepatic teratoma is exceedingly rare. There are several distinguishing characteristics of these benign tumors on radiographic evaluation; however, imaging techniques such as ultrasound scan, computed tomography, and angiography are not always reliable in differentiating benign from malignant tumors. The differential diagnosis of benign hepatic tumors includes nonneoplastic cystic masses including biliary and simple hepatic cysts, hematoma, parasitic cysts, and pyogenic and amebic liver abscess. Choledochal cyst presents with a classic triad of abdominal pain, cholestatic jaundice, and a palpable abdominal mass. They are classified anatomically into 5 subtypes with the most popular types being type I and type IV. Treatment is with complete cyst excision with hepaticojejunostomy reconstruction.

Fine-needle aspiration cytology of mesenchymal hamartoma of the liver

The cytologic appearance of mesenchymal hepatic hamartoma in a 2-yr-old boy is described. Smears disclosed small groups and isolated, benign-appearing spindle cells admixed with scarce amounts of myxoid stroma and normal ductal cells and hepatocytes. Although the findings were nonspecific, cytology may rule out many other diagnostic possibilities and increases the preoperative capacity of clinical and image studies, leading to a more rational therapeutic decision.

Undifferentiated embryonal sarcoma of the liver: results of clinical management in one center

PURPOSE

This study was undertaken to review the authors' clinical experience with undifferentiated embryonal sarcoma of the liver (UES) in children, focusing on the clinical presentation and results of treatment.

METHODS

A retrospective analysis of all children who have undergone treatment for UES during the 15-year period from 1984 through 1998 was performed.

RESULTS

Seven patients (4 boys and 3 girls) ranging in age from 20 months to 12 years at the time of diagnosis were identified. All presented with large abdominal masses and normal liver function test results. All underwent complete tumor resection; trisegmentectomy was required in 4 of these cases. All patients received postoperative chemotherapy. Two patients suffered tumor recurrence at 12 and 29 months; both of these patients died of their disease. Another patient died of complications related to chemotherapy. The other 4 patients are alive with no evidence of disease after 19 to 150 months' follow-up.

CONCLUSIONS

Undifferentiated embryonal sarcoma of the liver presents as a large hepatic tumor. Operative resection is difficult, but combined with adjuvant chemotherapy offers the best hope for cure.

Mesenchymal hamartoma of the liver--new insight into histogenesis

BACKGROUND/PURPOSE

Mesenchymal hamartoma (MH) of the liver is thought to develop from the ductal plates of the prenatal liver. This immunohistochemical study was performed to gain insight into the pathophysiology of its development.

METHODS

Specimens from four MHs with adjacent liver, in one case from a biopsy and from the resected lesion after 6 years follow-up, were investigated with immunostaining on cryostatsectionswith antibodies against cytokeratins, vimentin, desmin and alpha-actin, as well as von Willebrand factor (factor VIII), fibroblast growth factor (FGF) receptors, FGF-1 (acidic FGF), FGF-2 (basic FGF), and the proliferation-associated Ki67 antigen.

RESULTS

Fibrous tissue of MH stained positive not only for vimentin, but also for desmin and alpha-actin, whereas cytokeratins and factor VIII showed specific staining in biliary cysts and endothelial cells, respectively. All mesenchymal cells expressed proteins of the FGF receptor family. Although FGF-1 was only scarcely detectable, there was an accumulation of FGF-2 in borderline areas of liver to MH. Multiple Ki67-positive mesenchymal cells could be identified in these regions in all three MHs. However, we could not detect any proliferative activity in the MHs after follow-up.

CONCLUSIONS

The proliferative process in MH is still active during early childhood. FGF-2 may have a role in promoting this process. The positivity for desmin and alpha-actin of the lesions suggests that fat-storing (Ito) cells of the immature liver may be involved in the development of MH.

Pediatric liver tumors

An infant or child who presents with a large intrahepatic mass will most likely have a malignant tumor. In children, benign tumors constitute only 30% of liver tumors and most are vascular in origin. Treatment of benign vascular tumors is conservative and seldom surgical. Hepatoblastoma is the most common malignant tumor followed by hepatocellular carcinoma. Treatment of malignant tumors is based on a combination of surgery and chemotherapy. Children with hepatic malignancies that can be resected have an excellent prognosis. Other rare benign and malignant tumors of the liver do occur and surgery plays a critical role in management.

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.