Mesenchymal hamartoma of the liver: report of a case in a 28-year-old

A case of adult undifferentiated embryonal sarcoma of the liver successfully treated with right trisectionectomy: a case report

Background

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare malignant mesenchymal tumor that usually occurs in children and is rarely diagnosed in adults.

Case presentation

Here, we describe the case of a 65-year-old woman who presented with a huge cystic lesion in the liver. Laboratory studies performed on admission showed modest inflammation, poor nutrition, and elevated levels of total bilirubin, alkaline phosphatase, and γ-glutamyl transferase. Computed tomography showed a well-defined, heterogeneous tumor with multiple cysts involving the right lobe and the medial segment of the liver, with a maximum diameter of 16 cm. Positron emission tomography/computed tomographic scans showed the uptake of 2-(fluorine-18)-fluoro-2-deoxy-d-glucose in a part of the cyst. The patient was diagnosed with mucinous cystadenocarcinoma or sarcoma of the liver and underwent right trisectionectomy. Histopathological studies revealed that the tumor was composed of pleomorphic and polynuclear dyskaryotic cells with eosinophilic globules in the cytoplasm. Mesenchymal hamartoma-like tissue was observed in the peripheral part of the tumor. Immunohistochemical analyses showed the tumor stained with vimentin, α-smooth muscle actin, desmin, α1-antitrypsin, and α1-antichymotripsin. Therefore, a histological diagnosis of UESL was made. Eighteen months following treatment, two recurrent tumors in the remnant liver were detected and resection of the recurrent tumors was performed.

Conclusions

A UESL should be considered in the differential diagnosis of large cystic hepatic lesions. Although the prognosis of UESL is extremely unfavorable, aggressive surgical resection should be the most important factor for ensuring long-term survival.

Mesenchymal Hamartoma of the Liver in Older Children: An Adult Variant or a Different Entity? Report of a Case With Review of the Literature

Mesenchymal hamartoma of the liver (MHL) is an uncommon benign hepatic tumor typically affecting children under 2 years of age. Only 5% of MHL occur after 5 years and are very rarely observed in adults. According to age, MHL may differ in their morphologic features. We report a case of an 11-year-old boy with MHL, resembling a malignant lesion from a clinical point of view, characterized by unusual histologic features: a prominent myxoid stroma, with a minimal ductular component, and absent cystic spaces. The present case and others reported in older children or adults demonstrate that these lesions may represent a potential diagnostic pitfall when occurring outside their classic clinical context especially because of their peculiar histologic findings. Moreover, it may be hypothesized that variation in morphology might be related to different evolutive stages of the cell of origin. To support this hypothesis, we therefore studied the presence of components of the Notch pathway inside and outside the lesion. Their absence inside the tumor and, in contrast, the expression of Notch2 and HES1 evident in overrepresented bile ducts present at the periphery might explain not only the lack of bile ducts, but also indicate a more adult phenotype compared with classic pediatric MHL, which show more bile ducts and liver trabeculae embedded in the mesenchymal matrix.

Adult Mesenchymal Hamartoma of the Liver: Case Report and Literature Review

Mesenchymal hamartoma of the liver (MHL) is a rare benign lesion occurring primarily in the pediatric population. While the precise pathogenesis of the tumor is not certain, the most common theory relates to aberrant mesenchyme development in the portal tract likely related to the bile ducts. A 53-year-old female was evaluated for an incidental liver mass. Initial CT scan showed a cystic lesion in the right lobe of the liver and follow-up imaging revealed an increase in size and the percent solid component within the mass. In view of these changes, a nondiagnostic biopsy was obtained followed by extirpation of the lesion. Gross pathological review of the lesion identified a 9 × 9 × 7.5 cm, pink-yellow-tan, gelatinous mass, with a >1 cm clear surgical margin. Histologically, the mass consisted of benign dilated bile ducts, as well as myxoid stroma with spindle cells showing smooth muscle differentiation. The patient was discharged home on postoperative day five. A review of the literature for MHL in adults reports 30 previous cases, predominantly published as individual case reports describing the size, lobe(s) of the liver affected, and the cystic/solid nature of the tumor. MHL in adults may represent a potentially premalignant lesion, as the emerging literature supports a potential relationship between MHL and malignant undifferentiated embryonal sarcoma in regards to cytogenetic analysis. Aggressive surgical management of MHL in adults is mandated when feasible.

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 in adulthood: immunohistochemical profiles, clinical and histopathological features in two patients

Mesenchymal hamartoma is an uncommon cystic mass of the liver which occurs primarily in children. There are a few reports of its occurrence in adulthood. Here, we present two cases in female patients, 54 and 51 years old. Radiological examinations in both patients showed multiple cystic lesions in the liver. Surgically, total cystectomy was performed in the first patient, while an unroofing procedure was done in the second patient (due to misdiagnosis of the lesion as a simple cyst of the liver). On microscopic examinations of the lesion in each patient, a multilocular cyst was observed, lined by flattened epithelium and surrounded by a mesenchymal component composed of mature connective tissue, arterial and venous vascular structures, peripheral nerve bundles, and ductal structures. An immunohistochemical panel consisting of desmin, smooth-muscle actin, S-100, vimentin, CD34, carcinoembryonic antigen, pancytokeratin, cytokeratin 7, cytokeratin 8, cytokeratin 17, cytokeratin 18, cytokeratin 19, and cytokeratin 20 was applied to paraffin sections. Immunoreactivity for cytokeratin 7 and cytokeratin 19 was observed in cystic epithelium and ductal structures. Focal and patchy desmin immunoreactivity was observed in connective tissue. S-100 was positive only in peripheral nerve bundles. In conclusion, mesenchymal hamartoma of the liver in adulthood is a localized tumoral abnormality that precedes birth, and which has delayed clinical presentation. These lesions seems to be related to a maturation process. During this period of maturation, immature edematous stroma rich in mucopolysaccharides may convert to mature paucicellular hyalinized connective tissue. This maturation process may be also related to loss of premalignant potential of these tumors.

Mesenchymal hamartoma of the liver in the adult: association with distinct clinical features and histological changes

Mesenchymal hamartoma of the liver (MHL) is an uncommon mass lesion composed of architecturally abnormal bile ducts in an uncommitted myxoid stroma. Most MHL are diagnosed in childhood. More than 50% of cases are seen in the first year of life, although a few cases have been previously reported in adults. The spectrum of pathological findings in the cases presenting in adults, including differences in comparison with MHL in children, has not been fully characterized. In this report, we describe 3 cases of MHL in patients 46, 63, and 66 years of age. Each of the patients was a woman who had a solid or multicystic hepatic mass ranging from 5 to 24 cm in maximum dimension. In contrast to the childhood cases, the stromal component was fibrotic with areas of dense hyalinization and only focal myxoid areas. In 1 case, the mesenchymal component was the predominant feature of the lesion, with only occasional ductal elements identified with thorough tissue sampling. Immunohistochemical analysis with a panel of antibodies showed that, as in normal bile ducts, the ductal structures within the lesion were immunoreactive for cytokeratin 7 and negative for cytokeratin 20. The stroma was composed of a prominent population of fibroblasts and myofibroblasts that were positive for smooth muscle actin and vimentin. Analysis of the current findings, together with the previous case reports, shows that in contrast to MHL in children, this lesion in adults is found more commonly in women who present with abdominal pain. Recognition of the clinicopathologic differences between adult and pediatric cases will facilitate accurate diagnosis of this uncommon lesion.

Benign liver tumors

Benign liver tumors are becoming a subject of great interest because increased access to medical care has allowed discovery of many incidental focal lesions. These tumors may be hepatocellular, biliary, or stromal in nature. Several new lesions have been described in recent years causing a need to reassess the pathogenesis and classification of hepatic tumors. Hepatocellular nodules may be neoplastic or a regenerative response to injury. The size and structure of regenerative nodules varies with the distribution and severity of the hepatic injury, leading to a complex classification. Variation in fat content is easily detected on ultrasonography as focal fatty change and focal fatty sparing. Biliary and stromal cells also produce neoplastic or regenerative lesions. Biliary lesions are often cystic in nature. Stromal lesions are varied because of the many nonparenchymal cell types in the liver.

Hepatic undifferentiated (embryonal) sarcoma arising in a mesenchymal hamartoma

We report the case of a hepatic undifferentiated (embryonal) sarcoma (UES) arising within a mesenchymal hamartoma (MH) in a 15-year-old girl. Mapping of the tumor demonstrated a typical MH transforming gradually into a UES composed of anaplastic stromal cells. When evaluated by flow cytometry, the MH was diploid and the UES showed a prominent aneuploid peak. Karyotypic analysis of the UES showed structural alterations of chromosome 19, which have been implicated as a potential genetic marker of MH. The histogenesis of MH and UES is still debated, and reports of a relationship between them, although suggested on the basis of histomorphologic similarities, have never been convincing. The histologic, flow cytometric, and cytogenetic evidence reported herein suggests a link between these two hepatic tumors of the pediatric population.

Mesenchymal hamartoma of liver in a man: comparison with cases in infants

A 53 year old man with a large mesenchymal hamartoma is reported. Only a few bile ducts could be found in the periphery of the lesion and no hepatocytes were identified within the lesion. As far as is known, this is the only adult male patient reported to date. On the basis of the reported findings of mesenchymal hamartoma in other adults, it is suggested that there could be changes in the morphology of this lesion with age: progressive loss of hepatocytes; degeneration of bile duct epithelium; and cystic change of the mesenchymal component. The haematopoietic element is considered to be part of the fetal hepatic haematopoiesis that occurs in the hamartoma.

Adult mesenchymal hamartoma of the liver mimicking bile duct cystadenoma

We report a rare case of mesenchymal hamartoma in the cirrhotic liver of a 52-year-old Japanese male. The tumor, 3.5 cm in diameter, contained a cystic lesion and was located in the lateral segment. Bile duct cystadenoma was considered most likely preoperatively because of the patient's age and the normal levels of tumor markers. However, since malignancy of the lesion could not be ruled out by preoperative imaging diagnosis, lateral segmentectomy was performed. Histological examination led to a diagnosis of mesenchymal hamartoma, since the lesion consisted of a multilocular abnormal bile duct accompanied by abundant myxomatous or loose collagen.

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.