Osteoclastoma-like giant cell tumor of the liver

Undifferentiated carcinoma of the liver with osteoclast-like giant cells: a case report and literature review

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. Osteoclast-like giant cells (OGCs) are relatively more common in pancreatic cancer, but extremely rare in HCC. Currently, there have been only a few reported cases of OGCs in HCC, and their presence indicates an aggressive clinical course. Here, we present a case of primary undifferentiated carcinoma of the liver with OGCs in a 49-year-old male patient, and through a literature review, we summarize 20 similar cases to further understand the diagnosis, treatment, and clinical course of this disease entity.

A unique case of lymphoepithelioma-like HCC with osteoclast-like giant cells: CT imaging features with pathologic correlations

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver, with several histological variants being reported in literature. Hereby, we describe a case of a 77-year-old man with chronic liver disease referred to our department for performing a computed tomography (CT) due to a liver mass discovered at an abdominal ultrasound follow-up. At CT, a large, ill-defined lesion in the third hepatic segment was detected, characterized by progressive and delayed enhancement with minimal retraction of the hepatic capsule, associated with perihepatic adipose tissue inhomogeneity, mimicking a cholangiocarcinoma. At histopathological evaluation, the lesion turned out to be an HCC with lymphoepithelioma-like component and osteoclastic-like giant cells. This report focuses on the clinicopathological and radiological features of this unique case.

Osteoclast-like giant cells in hepatocellular carcinoma case description and review of the literature

BACKGROUND

The presence of osteoclast-like giant cells (OGC) in hepatocellular carcinoma (HCC) is rare and literature on this topic is scarce. In this article, we report on a case of a 77-year-old male patient with HCC with OGC and provide an overview of the current literature.

METHODS

We conducted a systematic search to find all available literature on OGC in HCC. The electronic databases PubMed, Web of Science, Embase and CENTRAL were searched from inception until October 2020.

RESULTS

Thirteen articles on this topic were identified and were included in this review. Data on 14 patients were available, described in twelve case reports, one patient in a patient series and the present case. Median age of included patients was 68 years. Two patients underwent neoadjuvant therapy prior to surgery. Of the 14 cases, eight tumours with OGC arose in a cirrhotic liver. Oncological outcome in this series was unfavourable, even after surgical resection, with a median disease-free survival of 75 d.

CONCLUSIONS

The presence of OGC in HCC is rare. Current literature is scarce, and suggests an unfavourable outcome in regard to overall survival of HCC.

Primary undifferentiated carcinoma with osteoclast-like giant cells in liver and rapidly developing multiple metastases after curative hepatectomy: a case report

A 64-year-old man was diagnosed with cholangiocellular carcinoma based on preoperative computed tomography and magnetic resonance imaging and underwent laparoscopic segmentectomy (Segment 8) of the liver for radical operation. Pathological examination revealed the presence of an undifferentiated carcinoma with osteoclast-like giant cells, which were categorized as T3N0M0 and Stage III based on the third English edition of the Japanese classification of liver cancer. The patient was treated with three courses of combination chemotherapy, which included gemcitabine (1000 mg/m²) and cisplatin (25 mg/m²), as well as S-1 (120 mg/day) for adjuvant chemotherapy. At two months after the operation, CT revealed multiple liver- and lung metastases. Thereafter, the patient was prescribed the molecularly targeted drug, lenvatinib (12 mg/day). However, lenvatinib was not effective, as evident by the extension of several metastases. Testing for microsatellite instability was negative. The patient died 5 months after the operation. We experienced a case of primary undifferentiated carcinoma with osteoclast-like giant cells in the liver showed rapidly developing multiple metastases after curative liver resection.

An expanded immunohistochemical profile of osteoclast-rich undifferentiated carcinoma of the urinary tract

Osteoclast-rich undifferentiated carcinoma of the urinary tract (ORUCUT) is a rare tumor composed of ovoid to spindle-shaped mononuclear cells with intermixed or focally clustered osteoclast-like giant cells. Previous studies have demonstrated that the mononuclear cells are neoplastic cells, while the giant cells are reactive cells of histiocytic lineage. The association between these tumors and classic urothelial carcinomas suggest that the mononuclear cells are derived from urothelial cells; however, no studies have been conducted to assess the immunohistochemical profile of ORUCUT with more specific urothelial markers. This study identified 21 cases of ORUCUT and performed immunohistochemistry for GATA3, uroplakin II, and thrombomodulin along with pancytokeratin (AE1/3) on all cases. Mononuclear cells stained positive in 20 cases (95%) for GATA3 and 19 cases (90%) for thrombomodulin. None of the mononuclear cells were positive for uroplakin II and only three cases showed focal positivity for AE1/3. The osteoclast-like giant cells were negative for GATA3, uroplakin II, thrombomodulin, and AE1/3, providing additional support to a reactive origin for these cells. Additionally, 15 cases (71%) were associated with either in situ or invasive urothelial carcinoma. This study provides an expanded immunohistochemical profile for ORUCUT and more definitively supports a urothelial origin for this tumor.

Pleomorphic Carcinoma of the Gallbladder: Report of a Case

The authors report a rare case of primary pleomorphic carcinoma of the gallbladder in a 70-year-old woman. A polypoid tumor protruded into the lumen from the fundus of the gallbladder. Characteristic histologic findings Included a general lack of architectural cohesiveness, marked pleomorphism, presence of mononucleated and multinucleated giant cells, extensive necrosis, leukocyte-tumor cell phagocytosis or cannibalism. Immunoreactivity for cytokeratin, carclnoembryonic antigen and epithelial membrane antigen as well as histochemical positivity for mucins demonstrated the epithelial nature of the tumor. The neoplasm behaved aggressively; the patient died of metastases 9 months after the operation.

Pathologic Features of Primary and Metastatic Hepatic Malignancies

In the mammalian liver, 60 % of the cellular components are hepatocytes while the remainder (35 %) includes biliary epithelium, Kupffer cells, endothelial cells, fat storing cells and connective tissue cells. Although neoplasms of hepatocytes are the most common, a significant number of both benign and malignant primary liver neoplasms arising from other cell types can develop, such as tumors of bile duct epithelium (Table 1). In addition, the liver is one of the most susceptible sites for metastatic tumors arising from other organs of the body. Not too long ago, liver tumors were left untreated because the liver was considered a complex and mysterious organ inaccessible to surgery. Advances in imaging procedures and surgical techniques over the past 40 years have revolutionized the approaches to the treatment of benign and malignant liver tumors. Subsegmentectomy, segmentectomy, lobectomy, and transplantation are routinely performed for the treatment of primary and metastatic liver tumors with minimal morbidity and mortality. Since accurate diagnosis remains the key to clinical and surgical management, the emphasis of this chapter is on classification, morphological features and differential diagnosis of malignant neoplasms of the liver.

Immunohistochemical evaluation of a sarcomatoid hepatocellular carcinoma with osteoclastlike giant cells

Background

Malignant liver tumors with osteoclast-like giant cells are rare. A literature search showed 17 previously reported cases that included the following: (1) 8 undifferentiated hepatocellular carcinomas, (2) 5 sarcomatous tumors with osteoclast-like giant cells associated with intrahepatic cholangiocarcinoma or liver cystadenocarcinoma, and (3) 4 sarcomatoid tumors with osteoclast-like giant cells associated with areas of a conventional hepatocellular carcinoma.

Case presentation

A 68-year-old man presented with a tumor of the right lobe of the liver on ultrasonography and computed tomography. Laparoscopy showed a tumor (diameter, 4 cm) in segments 7 and 8 of the right liver lobe that adhered to the retroperitoneum. The tumor recurred 3 months after liver segmentectomy. Repeat laparoscopy showed diffuse and nodular metastases to the omentum and peritoneum.

Result

Light microscopy showed that part of the tumor had features of classic hepatocellular carcinoma. Another part of the tumor had a solid sarcomatous pattern with osteoclast-like giant cells that were irregularly distributed between the smaller undifferentiated tumor cells; cells of this part of the tumor were positive for heppar-1.

Conclusion

Light microscopic findings including osteoclast-like giant cells, and the strong reaction of heppar-1 antibody with cells of the sarcomatous part of the tumor, confirmed that this sarcomatous element was a metaplastic or transformed portion of hepatocellular carcinoma.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6000512901462616

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-015-0274-4) contains supplementary material, which is available to authorized users.

Hepatocellular carcinoma with osteoclast-like giant cells: report of the seventh case in the literature

Hepatocellular carcinoma with osteoclast-like giant cells is extremely rare, and only six cases have been previously reported. Its histogenesis is at the moment controversial. The authors report a case of hepatocellular carcinoma with osteoclast-like giant cells found in a 74-year-old woman. The patient came with a dull pain in the right upper abdominal quadrants due to a liver neoplasm described at CT scan. A wedge resection of the fifth hepatic segment with appendectomy, omentectomy, and debulking of the major peritoneal implants was performed. Histologically, the diagnosis of hepatocellular carcinoma with high grade differentiation associated with giant osteoclast-like cells was done without any evidence of hepatitis or cirrhosis in the surrounding hepatic parenchyma. Immunohistochemistry was positive for CD10 and CD68 and in situ hybridization revealed the expression of receptor activator of nuclear factor-kappa B (RANK) in the giant cells and receptor activator of nuclear factor-kappa B ligand (RANKL) in the tumor cells.

Osteoclast-like giant cell tumors of the pancreas and liver

Osteoclast-like giant cell tumors (OGCT) are rare abdominal tumors, which mainly occur in the pancreas. The neoplasms are composed of two distinct cell populations and frequently show an inhomogenous appearance with cystic structures. However, due to the rarity of these tumors, only very limited clinical data are available. Imaging features and sonographic appearance have hardly been characterized. Here we report on two cases of osteoclast-like giant cell tumors, one located within the pancreas, the other within the liver, in which OGCTs are extremely rare. Both patients were investigated by contrast sonography, which demonstrated a complex, partly cystic and strongly vascularized tumor within the head of the pancreas in the first patient and a large, hypervascularized neoplasm with calcifications within the liver in the second patient. The liver OGCT responded well to a combination of carboplatin, etoposide and paclitaxel. With a combination of surgical resection, radiofrequency ablation and chemotherapy, the patient’s survival is currently more than 15 mo, making him the longest survivor with an OGCT of the liver to date.

Osteoclast-rich undifferentiated carcinomas of the urinary tract

Osteoclast-like giant-cell neoplasms of the urinary tract are rare. They are composed of ovoid or spindle-shaped mononuclear cells with evenly spaced osteoclast-like giant cells. Terminology, histogenesis, and biologic behavior of these tumors remain controversial. Six cases of osteoclast-like giant-cell neoplasms of the urinary tract were identified from the consultation files of two of the authors. Patients were all male and elderly (range 65-82), with the exception of one 39-year-old male. In all, 3/6 tumors developed in the bladder and 3/6 in the renal pelvis. Size ranged from 5 to 11 cm. One bladder and three renal pelvis tumors were high stage (pT3) at time of presentation. Adjacent to the osteoclast-like giant-cell neoplasm in the same specimen, all patients had urothelial carcinoma in situ and/or high-grade papillary urothelial carcinoma. Multinucleated cells had identical morphological and immunohistochemical properties of osteoclasts; positive for CD-68, LCA, CD51 and CD54, and negative for cytokeratins and EMA. Varying percentages of mononuclear cells expressed alpha-smooth muscle actin (4/6), desmin (1/6), S-100 (4/6), LCA (2/6) and CD68 (6/6). However, mononuclear cells were also positive for epithelial markers in 4/6 tumors (cytokeratins AE-1/AE-3, Cam 5.2, CK7 and/or EMA). p53 stained mononuclear tumor cells in three cases, paralleling the staining on the accompanying urothelial carcinoma. Ki-67 stained mononuclear tumor cells, but not osteoclast-like giant cells. Follow-up data were available in five cases. One patient developed recurrence of noninvasive urothelial carcinoma and is still alive. Four patients were dead due to disease within 15 months, three with distant metastases. The intimate association of these tumors with urothelial carcinoma along with their immunohistochemical profile supports an epithelial origin for the mononuclear cells and non-neoplastic reactive histiocytic lineage for the osteoclast-like giant cells.

Osteoclast-like giant cell tumor of the liver: a rare neoplasm with an aggressive clinical course

Osteoclast-like giant cell tumors (OCGTs) usually involve the bone and rarely affect the alimentary tract. Within the gastrointestinal tract the liver has been one of the most infrequently reported locations for this neoplasm to occur. In this article we report the occurrence of an OCGT arising in the liver of a 61-year-old woman. The patient presented with abdominal pain and a rapidly enlarging hepatic mass. Magnetic resonance imaging (MRI) indicated a multilocular solid lesion in the right lobe of the liver. A small extrahepatic lobulation at the lateral aspect of the lesion with penetration of the capsule was visible. Local extension into adjacent organs was not evident. Positron emission tomography (PET) did not indicate a tumor in the pancreas or elsewhere in the body. The tumor was removed by performing a formal right hepatic lobectomy. Histologic and immunohistochemical examinations revealed an OCGT. Within 3 months of the hemihepatectomy, widespread intraabdominal and pulmonary metastasis developed and the patient succumbed to her illness shortly thereafter. This report contributes further evidence to the aggressive biological behavior with regard to this rare neoplasm. The absence of metastatic disease indicated when using magnetic resonance imaging and positron emission tomography does not seem to change the overall dismal prognosis of this tumor.

Osteoclast-type Giant Cell Neoplasm of Salivary Gland. A Microdissection-based Comparative Genotyping Assay and Literature Review

Primary salivary gland tumors resembling giant cell tumor of bone are very rare and have unsettled histogenesis. Both mesenchymal and epithelial origins have been suggested. We review 14 cases in the English-language literature and report another case, the first of which to be studied by microdissection-based microsatellite analysis. One-half of the tumors have been associated with a carcinoma, usually salivary duct carcinoma and carcinoma ex pleomorphic adenoma. Significant differences between this tumor and giant cell tumor of bone were observed. Unlike giant cell tumor of bone, in which the nuclei of the mononuclear and giant cells are similar, those of salivary gland show obvious differences between the nuclei of mononuclear cells and osteoclastic giant cells. In addition and in contrast to giant cell tumor of bone, the mononuclear cells of giant cell tumor of salivary gland express epithelial markers (epithelial membrane antigen, EMA; carcinoembryonic antigen, CEA) and androgen receptor. Genotypically, the microsatellite pattern of the giant cell component is more akin to the carcinomatous component and does not resemble giant cell tumor of bone. Biologically, giant cell tumor of salivary gland tends to be more aggressive than giant cell tumor of bone. We conclude that giant cell tumor of salivary gland is an unusual carcinoma that is not related to giant cell tumor of bone.

Hepatocellular carcinoma with osteoclast-like giant cells: possibility of osteoclastogenesis by hepatocyte-derived cells

Giant cell tumor (GCT) of bone is a primary osteolytic tumor that is characterized by the formation of osteoclast-like giant cells. In addition to GCT of bone, extraskeletal GCT are known to be formed in several soft tissues. Giant cells in GCT of bone were suggested to be identical to osteoclasts, but the characterization of giant cells in extraskeletal GCT remains incomplete. In this study, a case of sarcomatoid hepatocellular carcinoma with osteoclast-like giant cells was analyzed. Immunohistochemistry revealed the expression of almost all markers of osteoclasts: tartrate-resistant acid phosphatase, CD68, CD51, CD54 and matrix metalloprotease-9, in osteoclast-like giant cells in the tumor. In situ hybridization revealed the expression of receptor activator of nuclear factor-kappa B (RANK) in the giant cells and receptor activator of nuclear factor-kappa B ligand (RANKL) in the tumor cells. The hepatic origin of the sarcomatoid hepatocellular carcinoma cells was confirmed by the expression of albumin. This is the first report suggesting that hepatocyte-derived cells possess the potential for osteoclastogenesis. In addition, these findings suggest that osteoclast-like cells in the hepatocellular carcinoma were formed by the same mechanism as osteoclastogenesis in bone.

Immature hepatic tumor of bimodal differentiation in a young adult patient: a novel lesion expressing beta-catenin and mimicking a distinct phase of hepatogenesis

PATIENT AND METHODS

A large right-sided liver tumor was incidentally discovered and totally resected in a 21-year-old female patient without chronic liver disease. Histopathologic examination revealed that this malignant tumor does not fit any of the known types of primary liver tumors reported thus far.

RESULTS

The lesion chiefly consisted of numerous solid nests composed of immature epithelial cells disclosing a marker profile typical for hepatocytes and strongly expressing beta-catenin. These nests were tightly associated with abnormal duct-like profiles exhibiting features of bile duct cells.

CONCLUSIONS

The finding of numerous neoplastic hepatobiliary units ('liverlets') suggests that this tumor may mimic a distinct developmental phase of hepatogenesis close to ductal plate formation.

Osteoclastoma-like Giant Cell Tumor of the Lung

The main components of an unusual form of lung tumor were osteoclast-like multinucleated giant cells and mononuclear stromal cells. Besides, scattered islands of moderately differentiated squamous cells also appeared. Both the mononuclear and the osteoclast-like giant cells reacted with antibodies against CD68 and vimentin, but did not react with antibodies against cytokeratin, EMA and CEA, or lysozyme and a-1-antitrypsin. The p53 and PCNA antigens were positive only in mononuclear cells and not the osteoclast-like giant cells, suggesting that mononuclear cells represent proliferating elements with histiocytic differentiation while osteoclast-like giant cells are stromal, presumably reactive components of the tumor.

K-ras oncogene mutations in osteoclast-like giant cell tumors of the pancreas and liver: genetic evidence to support origin from the duct epithelium

Osteoclast-like giant cell tumors (OCGTs) of the pancreas and liver are enigmatic tumors. Despite their striking morphologic resemblance to certain mesenchymal tumors of bone and tendon sheath, it has been suggested that these tumors may, in fact, arise from epithelial precursors. It is also unclear whether the osteoclast-like giant cells in OCGTs are neoplastic or nonneoplastic. We identified OCGTs of the pancreas and liver that were associated with atypical intraductal epithelial proliferations or mucinous cystic neoplasms. To determine the relationship between the noninvasive epithelial proliferations and the infiltrating OCGTs, each individual component was analyzed for mutations at codon 12 of the K-ras oncogene. Four of the five-duct epithelial lesions harbored activating mutations of the K-ras oncogene. In each case, the same K-ras mutation was also present in the mononuclear cells from the paired OCGT. Moreover, these same mutations were detected when the osteoclast-like giant cells were individually microdissected and analyzed. A panel of immunohistochemical stains was performed, and the osteoclast-like giant cells demonstrated macrophage differentiation. These cells were consistently reactive for the monocyte/macrophage marker KP1, but showed absent staining for a panel of epithelial markers. The infiltrating mononuclear cells lacked strong staining for epithelial markers and monocyte/macrophage markers. These findings suggest that OCGTs of the pancreas and liver are undifferentiated carcinomas that arise directly from intraductal epithelial precursors. The finding of K-ras mutations in the osteoclast-like giant cells may reflect their propensity to phagocytize tumor cells.

Sarcomatoid hepatocellular carcinoma with osteoclast-like giant cells: case report and immunohistochemical observations

Hepatocellular carcinoma (HCC) with osteoclast-like giant cells (OGC) developed in the cirrhotic liver of a 42-year-old male. Serum protein induced by vitamin K absence or antagonist II was elevated preoperatively. The patient died of the disease on the 28th postoperative day. Histologically, the tumor consisted of OGC and mononuclear cells (MC). The OGC were characterized by benign-appearing nuclei, whereas the MC had atypical nuclei with a considerable number of mitoses. A vaguely trabecular pattern was observed in the focal area of the tumor, but no evidence of overt HCC was found. Immunohistochemical analysis revealed that both OGC and MC were diffusely positive for histiocytic and mesenchymal markers. Some MC were focally positive for cytokeratins 7, 8 and 19, and for albumin. Our clinical, histological and immunohistochemical findings suggest that the MC were derived from hepatocytes, with some mesenchymal features, but the OGC were non-neoplastic and reactive histiocytes.

Uterine leiomyosarcoma with osteoclast-like giant cells: histopathological and cytological observations

A 56 year old woman presented with abnormal uterine bleeding. Except for a myomatous uterus, no other abnormalities were noted on physical examination and in radiographic and serologic studies. The hysterectomy specimen revealed an 8 cm uterine fundic tumor composed of two histologically different patterns that merged with one another; one was a well differentiated leiomyosarcoma and the other a mixture of osteoclast-like giant cells (OGC) and plump spindle cells whose cell borders blended, resembling the histology of giant cell tumor of bone. Immunohistochemical studies showed positive staining for muscle actin, alpha-smooth muscle actin, and KP-1 (CD68) in both the spindle cells and OGC. The latter also stained for alpha-1-antitrypsin and alpha-1-antichymotrypsin. These findings suggested that OGC may be formed by the fusion of spindle cells of leiomyosarcoma and also express histiocytic markers.

Proliferation of osteoclast-like giant cells in a metastatic bone tumor from stomach cancer: report of a case and analysis of the autopsy findings

A 70-year-old man who had undergone esophagectomy with reconstructive surgery using a portion of the stomach 5 years earlier for esophageal cancer was admitted to our hospital after a routine endoscopy and histological examination of a biopsy specimen revealed poorly differentiated adenocarcinoma in the stomach. A gastrectomy and intrathoracic esophagojejunostomy was performed on January 20, 1993; however, the patient suffered a cerebral infarction and died of septic shock on April 9, 1993. At autopsy, metastatic tumors were macroscopically observed in various organs, including a bone tumor measuring 1.0 cm in diameter in the L4 vertebra. To clarify the origin of the bone tumor, we conducted histological and immunohistochemical examinations. Histological examination revealed a mixture of osteoclast-like giant cells (OGCs) and poorly differentiated adenocarcinoma cells, although no histologic features of OGCs were observed either in a primary site or in any of the multiple metastatic lesions. On immunohistochemistry, adenocarcinoma cells in the bone stained positively for the carcinoembryonic antigen (CEA), whereas no staining for CEA was observed in the OGCs which demonstrated negative staining for all the antigens of epithelial markers. These findings led us to conclude that this bone tumor had metastasized from the stomach cancer and that the OGCs may have originated from mesenchymal cells reacting to the adenocarcinoma cells.

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.

Giant cell tumor of the lung: an autopsy case report with immunohistochemical observations

Tumors resembling giant cell tumor (GCT) of bone are well known to occur in other organs and many cases have been reported to date. While GCT occurring as primary lesions in the lung are extremely rare, the authors experienced such a tumor at an autopsy of a 77 year old woman and subsequently performed histological and immunohistochemical examinations. The clinical and morphologic characteristics of this case are documented, and the literature concerning this type of tumor is reviewed. The present tumor of the lung was histologically characterized by proliferation of benign-looking osteoclast-like giant cells in association with slightly atypical mononuclear cells. The tumor cells were immunohistochemically positive for histiocytic markers but negative for epithelial markers. This case appears to be the first reported benign giant cell tumor of the lung in which histiocytic differentiation of mononuclear cells was suggested by immunohistochemistry.

Renal cell carcinoma with osteoclast-like giant cells

Primary extraskeletal epithelial neoplasms with osteoclast-like giant cells are rare. We describe a case of renal cell carcinoma with a sarcomatoid component and non-neoplastic osteoclast-like giant cells. The giant cells were noted in both the conventional and the sarcomatoid components of the neoplasm. Immunohistochemical studies indicate that these cells are monocyte/histiocyte in origin and most probably a host stromal reaction to the neoplasm.

Osteoclast-like giant cell tumour of the gallbladder

We describe a rare carcinoma of the gallbladder containing osteoclast-like giant cells. Well-differentiated adenocarcinoma was found in the mucosa of the fundus, and osteoclast-like giant cells were present mainly in a haemorrhagic mass protruding from the mucosal surface. The metastatic hepatic tumour was composed chiefly, if not exclusively, of osteoclastoma-like cells, but minute carcinomatous elements were also present. There was an apparent transition between the giant cells and tubular structures in both the gallbladder tumour and hepatic tumour. However, ultrastructural study did not reveal any evidence of epithelial differentiation in the giant cells. Immunohistochemical studies suggested that the mononuclear and giant cells were mesenchymal and histiocytic in nature (vimentin and factor XIIIa positive). A few exceptional giant cells transforming from the fine tubular structure were positive for epithelial membrane antigen. In conclusion, the osteoclast-like giant cell tumour component was thought to represent mesenchymal metaplasia in pre-existent adenocarcinoma.

Giant cell tumor-like cholangiocarcinoma associated with systemic cholelithiasis

A cholangiocarcinoma of the hepatic hilus with an element of giant cell tumor that occurred in a 59-year-old man is reported. His medical history included systemic cholelithiasis and repeated operations on the biliary passages. Four years after the last operation, which was a hepatic segmentectomy, he was readmitted because of persistent fever. A computed tomography scan showed a low-density area and stones in the hepatic hilus. He died of hepatic failure approximately 1 month later. At autopsy, a fist-sized tumor and gallstones were found at the hepatic hilus. Histologically, the tumor mainly showed sarcomatoid features and some tubular adenocarcinoma. An element of giant cell tumor consisting of many osteoclast-type giant cells also was noted. The results of immunohistochemical studies showed a positive reaction to cytokeratin and vimentin in some of the spindle-shaped sarcomatoid cells. Sarcomatoid bile duct carcinomas are rare, as are those with osteoclast-type giant cells. The authors also discuss the histogenesis of these giant cells.

Osteoclasts: structure and function

Osteoclasts are multinucleated giant cells showing specialized membrane structures, clear zones and ruffled borders, which are responsible for the process of bone resorption. These cells arrive at the resorption site via the bloodstream as mononuclear cells, derived from haemopoietic precursors in the spleen or bone marrow, which fuse prior to resorption. The osteoclast may share an early progenitor cell, the granulocyte macrophage colony-forming unit (GM-CFU) with monocytes, macrophages and granulocytes, implying that osteoclasts share the pluripotent haemopoietic stem cell with all other haemopoietic cells. In the past, elucidation of the structure of these cells relied upon traditional ultrastructural techniques. Transmission electron microscopic studies revealed details of the unique ultrastructure of these cells and, in combination with stereological techniques, showed the response of cells to various hormonal stimuli. Scanning electron microscopy not only demonstrated the surface appearance of osteoclasts, and their predilection for spreading on various substratum components, but has also been used as an adjunct in resorption assays in which areas of resorption lacunae are measured as indicators of cell activity. Recent advances in fields such as immunocytochemistry and freeze fracture techniques have contributed towards a more detailed delineation of antigenic profile, cytoskeletal structure and localization of enzymatic pathways. The osteoclast is subject to extensive regulatory mechanisms and it has been established that the osteoblast plays a major rôle in mediating the effects of osteotropic hormones and local mediators on these cells. Hence, research aimed at elucidating the coupling mechanisms between these two cells may result in new therapies for bone disease.

Osteoclast-like giant cell tumour of the urinary bladder

We report two cases of osteoclast-like giant cell tumour of urinary bladder associated with papillary transitional cell tumours. Both cases were morphologically identical to giant cell tumour of bone. The giant cells stained strongly for acid phosphatase which was resistant to tartrate digestion, a staining reaction typical of osteoclasts. In view of the ability of urinary bladder to induce metaplastic and neoplastic bone, we believe that these tumours may represent extraosseous giant cell tumours of bone.

Osteoclast-like giant cell tumor of the liver

A 66-year-old male with osteoclast-like giant cell tumor of the liver that arose in the non-cirrhotic liver is presented. The liver tests were almost normal, and plasma levels of alpha-fetoprotein and carcinoembryonic antigen were within normal limits. The findings of liver scan by 99mTc phytate, celiac angiography, and CT scans are described for the first time for this rare neoplasm, showing a large, unresectable liver tumor. Histologically, the tumor mainly consisted of osteoclast-like giant cells and mononuclear cells, which were focally arranged in a vaguely trabecular pattern and sarcomatous pattern. By an electromicroscopic study, however, no definitive evidence was obtained whether it arose from epithelial cells or nonepithelial cells. Various clinicopathological features were described and compared with previously reported cases including two cases arising in the liver.

Undifferentiated carcinoma of the lung with osteoclast-like giant cells

We treated a patient with undifferentiated carcinoma of the lung, with osteoclast-like giant cells resembling those of the giant cell tumor of bone. The clinical and morphologic characteristics of this case are documented, and the literature concerning this type of tumor is reviewed. The tumor differed histologically from the pleomorphic carcinoma, which occurs most commonly in the lung, and showed diverse pleomorphic manifestation with benign looking osteoclast-like multinucleated cells and bizarre giant cells. In addition, and undifferentiated carcinoma with a sarcoma-like appearance containing small areas of papillary adenocarcinoma was evident in the tumor.

Malignant osteoclastoma-like giant cell tumour of the renal pelvis

We report the fourth case of an osteoclastoma-like giant cell tumour of the renal pelvis. A special feature was that although thorough sampling of the tumour showed an osteoclastoma-like pattern throughout, it was intimately associated with carcinoma in situ change of the adjacent transitional epithelium and this provides further support for the view that these tumours are of epithelial derivation. However, immunohistological and ultrastructural studies failed to reveal epithelial features within the tumour cells and the possible significance of this finding is discussed.

Squamous cell carcinoma of the larynx with osteoclast-like giant cells

An unusual squamous cell carcinoma of the larynx containing numerous multinucleated osteoclast-like giant cells in described. These cells occurred in areas of vigorous angiogenesis and haemorrhage. To our knowledge, this is the first case of laryngeal squamous cell carcinoma with osteoclast-like giant cells reported in the literature. The patient has remained alive and free of clinical disease 5 years and 4 months after the original diagnosis.

Malignant osteoclast-like giant cell tumor associated with a uterine leiomyosarcoma

An unusual case of osteoclast-like giant cell tumor associated with a leiomyosarcoma of the uterus is described. The mononuclear cell component of the giant cell tumor was cytologically malignant and the giant cell tumor was present in a biopsy of vaginal recurrence. The patient expired 17 months after diagnosis with extensive tumor despite surgical and radiation treatment. This is the first report of malignant osteoclast-like giant cell tumor associated with a uterine leiomyosarcoma and only the third report of osteoclast-like giant cell tumor in the uterus.

Giant cell tumor of the bladder associated with transitional cell carcinoma

We report in detail the first giant cell tumor associated with transitional cell carcinoma of the bladder. The giant cell tumor was composed of multinucleated giant and mononuclear stromal cells, and was morphologically indistinguishable from giant cell tumor of the bone. The giant and transitional cell carcinomas showed no evidence of recurrence or metastasis 8 months after transurethral resection. No histogenetic correlation between the cancers was found.

Hepatocellular carcinoma with osteoclast-like giant cells

A case of dedifferentiated hepatocellular carcinoma with osteoclast-like giant cells resembling those of giant cell tumor of bone is presented. The clinicopathologic findings are described, and the literature concerning this type tumor is reviewed. The tumor differed histologically from a pleomorphic variant of hepatocellular carcinoma in that there were numerous osteoclast-like giant cells with numerous, small, uniform, benign-appearing nuclei. To the knowledge of the authors, there has been only one report of this type of tumor arising in the liver. The tumor contained a separate area of a histologically conventional hepatocellular carcinoma, in addition to the above giant cell areas.

Bronchogenic sarcomatoid squamous cell carcinoma with osteoclast-like giant cells

A 60-year-old man developed a widely metastatic spindle cell neoplasm with admixed osteoclast-like giant cells indistinguishable from malignant giant cell tumor of soft parts. Autopsy revealed a bronchogenic sarcomatoid squamous cell carcinoma that was the primary source of the sarcomatoid metastases. The osteoclast-like giant cells in the metastatic lesions were negative for lysozyme on immunoperoxidase staining. This finding suggested that the multinucleated giant cells were not formed as a cellular response to hemorrhage or to cellular debris induced by the tumor. Extraosseous neoplasms with osteoclast-like giant cells are rare neoplasms that may occur in a variety of organs. This case is the second reported case of a primary neoplasm in the lung that contained these osteoclast-like giant cells. These tumors may cause considerable diagnostic confusion.

Giant cell tumor of the kidney

A multinucleated giant cell tumor developed in the left renal pelvis of a 60-year-old man. The tumor was morphologically indistinguishable from giant cell tumor of bone and considered to be both primary and benign, with a follow-up period of one year and no evidence of either recurrence or metastasis.