Cytokeratin subunits of inclusion bodies in rhabdoid cells: immunohistochemical and clinicopathological study of malignant rhabdoid tumor and epithelioid sarcoma

Epithelioid Sarcoma: Diagnostic Features and Genetics

Epithelioid sarcoma (ES) is a rare, aggressive soft-tissue neoplasm of uncertain differentiation, characterized by nodular aggregates of epithelioid cells, which are immunoreactive to cytokeratins (CKs) and epithelial membrane antigen, and often for CD34. It has a propensity for multifocal disease at presentation, local recurrence, and regional metastasis. These are aggressive neoplasms with particularly poor prognosis after regional or distant metastatic disease, for which surgical resection is still the mainstay of treatment, and options for patients with metastatic disease remain undefined. There are 2 distinct variants: classic ES, which typically presents as a subcutaneous or deep dermal mass in the distal extremities of young adults and comprises nodular distributions of relatively uniform epithelioid cells with central necrosis, and the proximal variant, which has a predilection for proximal limbs and limb girdles and the midline of the trunk, which is composed of sheets of larger, more atypical cells with variable rhabdoid morphology. Both classic and proximal-type ESs are associated with the loss of SMARCB1/INI1 protein expression, but appear otherwise molecularly relatively heterogeneous. We review classic and proximal-type ES, discussing morphology, immunohistochemical and genetic findings, the differential diagnosis, and the future potential for targeted therapies.

Vulvar sarcomas: Short guideline for histopathological recognition and clinical management. Part 1

Malignant tumors of the female reproductive system are a serious health and social problem, as they are the second most common cause of death among women, after breast cancer. Their incidence has increased dramatically during recent years, probably due to the different sexual habits and changes in the prevalence of HIV/ AIDS and HPV virus carriers, among other factors. Vulvar tumors represent only 4% of all gynecological neoplasms, and they are fourth in frequency after tumors of the cervix, uterus, and ovary. Ninety eight percent of all vulvar tumors are benign and only 2% are malignant. The overall incidence of tumors with vulvar location is between two and seven cases per 100,000 women, and it increases with age, while the death rate is estimated at 0.7 per 100,000 women. Sarcomas of the vulva comprise approximately 1-3% of all vulvar cancers, with leiomyosarcomas, epithelioid sarcomas, and rhabdomyosarcomas being the most common among them. They are characterized by rapid growth, high metastatic potential, frequent recurrences, aggressive behavior, and high mortality rate. In this paper, we present the most common forms of sarcomas of the vulva (leiomyosarcoma, epithelioid sarcoma, malignant rhabdoid tumor, rhabdomyosarcoma) in order to emphasize the broad differential diagnosis, rare appearance, non-specific clinical picture, aggressive course, and high mortality.

Cutaneous malignant rhabdoid tumor in the palm of an adult

Malignant rhabdoid tumor is a rare tumor occurring mostly in the neonatal kidneys and central nervous system. Cutaneous malignant rhabdoid tumors are extremely rare in adults. The aim of the study was to report on the clinical, histologic, and immunophenotypic characteristics of this cutaneous malignant rhabdoid tumor which developed in an adult. A 27-year-old male complained of a right palm neoplasm that had been present for 6 months, which was initially diagnosed as an epithelioid sarcoma by biopsy. However, detailed investigation with immunohistochemistry enabled us to make a diagnosis of a rhabdoid tumor. The patient underwent radical abrasion, chemotherapy, and irradiation, and has survived for 1 year without relapse. Only 20 adult cases have been reported thus far in the English literature. We are reporting the 21^st case, who remains disease-free at 12 months. Complete resection and local irradiation may increase survival, because there is no standard and reliable curative chemotherapeutic regimen.

A novel case of rhabdoid colon carcinoma associated with a positive CpG island methylator phenotype and BRAF mutation

Colon carcinoma with rhabdoid characteristics is a rare, malignant tumor whose molecular alterations have not been clarified yet. We report a novel case of a colon adenocarcinoma with rhabdoid features in a 71-year-old woman, localized to the right colon and associated with local lymph node and liver metastasis. The patient died within 8 months from surgery despite target chemotherapy. The tumor was enriched in cells with a typical rhabdoid-type morphology displaying a marked and diffuse vimentin staining. Cells were also positive for epidermal growth factor receptor (EGFR), p53, Ki67, and β-catenin and negative for cytokeratin 20/cytokeratin 7, E-cadherin, and CDX2. Remarkably, the promoter regions of 4 of 5 specific genes that define the so-called "CpG island methylator phenotype," including mutL homolog 1 (MLH1), were methylated. Consistently, microsatellite instability was detected. A BRAF V600E mutation and no KRAS mutations were identified. Finally, 4 tumor suppressor gene promoters CDH1, CDKN1B, CDKN1C, and MGMT were not methylated. This is the first case of a colorectal carcinoma with rhabdoid features, "CpG island methylator phenotype," high microsatellite instability associated with a BRAF mutation, and patient poorer outcome.

Epithelioid sarcoma of the neck: case report

Epithelioid sarcoma is an aggressive, malignant tumour of the soft tissue which tends to arise in proximity to large tendons and aponeuroses. We report the case of a patient presenting with an epithelioid sarcoma arising in the neck. A 56-year-old man was referred with a three-year history of a sensory disorder as well as a slowly growing mass in his right neck. The patient underwent resection of the tumour by means of a conservative neck dissection. The final diagnosis, based on the histological and immunohistochemical findings, was epithelioid sarcoma. Radiotherapy was performed after the operation. The post-operative course was uneventful, and there was no local recurrence or distant metastasis.

Primary rhabdoid cancer of the ileum: a case report and review of the literature

Since the first publication of a rhabdoid cancer, described as an infrequent variant of Wilms' tumor, several cases of extrarenal rhabdoid tumor have been reported in the literature. Here, we report on a primary rhabdoid cancer of the small intestine, and give a review of the data available in the literature. An 81-year-old male patient was admitted to the Department of Internal Medicine with subileus and bloody stools. While gastroscopy and colonoscopy failed to identify a neoplastic disease, abdominal US and CT raised the suspicion of a malignancy involving the descending colon. Ileus-mandated laparotomy disclosed an obstructive tumor of the ileum. This segment was resected, followed by several relapses, and the patient died after a 7-month-period of non-relenting deterioration. Histological work-up of the numerous biopsies disclosed a cellular, solid, necrotic, hemorrhagic, and invasive tumor. The cancer cells were round-to-polygonal, and scattered bizarre pleomorphic cells with prominent nucleoli were common. The overall appearance of the neoplasm was highly similar in every specimen. The immunohistochemical phenotype of the malignant cells indicated rhabdoid characteristics. A thorough search of the literature revealed additional 22 cases of primary rhabdoid GI cancers. This report aims to call the pathologist's attention to the differential diagnostic importance of this entity.

Extrarenal rhabdoid tumors of soft tissue: Clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features

Malignant rhabdoid tumor (MRT) of the soft tissue is a rare and highly aggressive tumor that occurs in infancy or childhood. It predominantly involves a deep axial location such as the neck or paraspinal region. Microscopically, the tumor is composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies, arranged in sheets and nests. These characteristic 'rhabdoid cells' are also present in certain soft-tissue sarcomas such as synovial sarcoma, extraskeletal myxoid chondrosarcoma and leiomyosarcoma. The existence of rhabdoid cells in these other sarcomas is correlated with a worse prognosis for the patients. Cytogenetic and molecular analyses have shown abnormalities in the long arm of chromosome 22 and alteration of the hSNF5/INI1 (SMARCB1) gene in renal, extrarenal and intracranial MRT. This gene alteration has been considered to be a specific molecular event in MRT, but a recent study has also demonstrated frequent alteration of this gene in proximal-type epithelioid sarcoma (ES). Both MRT of soft tissue and proximal-type ES show immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. The tumor cells of proximal-type ES are also occasionally positive for CD34 and beta-catenin, whereas MRT of soft tissue has no immunoreaction for these markers. Detailed clinicopathological and immunohistochemical evaluations are necessary to distinguish MRT of soft tissue from proximal-type ES, because these tumors demonstrated a similar morphology and the same gene alteration.

Epithelioid sarcoma of Enzinger

Epithelioid sarcoma was named in 1970 in a classic paper by Enzinger, who expanded the observations in a larger series in 1985. He defined a sarcoma with a peak incidence in young adult males and a predilection for extremities, involving subcutis or deeper tissue and extending along tendon sheaths or aponeuroses. The tumor forms nodules with central necrosis surrounded by bland polygonal cells with eosinophilic cytoplasm and peripheral spindling. Fibromalike, angiomatoid, and proximal aggressive variants (with larger cells, prominent nuceloi, and rhabdoid change) have since been described. Epithelioid sarcomas regularly express vimentin, cytokeratins, and epithelial membrane antigen, and about half are positive for CD34, but a wide range of other antigens can be expressed. S100 protein, desmin, and FLI-1 are usually negative. The ultrastructure displays epithelial and mesenchymal features including myofibroblastic differentiation. There are no specific genetic findings but several cases display chromosomal abnormalities in the 22q region. The tumor has no normal cellular counterpart and differs from both synovial sarcoma and carcinoma. There is a wide differential diagnosis from numerous benign and malignant conditions, including granuloma annulare, melanoma, and epithelioid vascular neoplasms. Epithelioid sarcoma has a high recurrence rate, which can be reduced by adequate surgery, and up to 40% metastasize, to regional lymph nodes, to lung, and other locations including scalp. Adverse prognostic factors include large size, male sex, older age, necrosis, vascular invasion, rhabdoid cytomorphology, and inadequate excision. Thirty-six years after Enzinger's original account, epithelioid sarcoma remains a clinically and pathologically distinct, indolent but aggressive sarcoma of indeterminate lineage.

Malignant rhabdoid tumor in a pregnant adult female: literature review of central nervous system rhabdoid tumors

Rhabdoid tumors of the central nervous system are uncommon, aggressive childhood malignancies. The 13 described adult cases comprise both primary CNS tumors and malignant transformation of previously existing gliomas, meningiomas, and astrocytomas. Central nervous system rhabdoid lesions of adults have been diagnosed as primary malignant rhabdoid tumors, atypical teratoid/rhabdoid tumors, and more recently, rhabdoid glioblastomas. We report a case of a 20-year-old woman in her 30th week of pregnancy who presented with headache, nausea and blurry vision. MRI revealed a large rim-enhancing mass of the right occipital lobe. Gross total resection was achieved via a right parietal-occipital craniotomy. Pathologic evaluation revealed histology, electron microscopy and immunohistochemistry consistent with the diagnosis of malignant rhabdoid tumor. FISH studies were negative for the INI-1 genetic mutations and chromosome 22q deletion associated with childhood atypical rhabdoid/rhabdoid tumor in 75% of cases. The patient delivered her infant via caesarian section prior to initiating further therapy. We briefly describe the characteristics and current understanding of rhabdoid tumors, and review the literature comparing the 12 other cases of central nervous system rhabdoid tumors in adults. Furthermore, we consider and discuss the implications of this case being the second presentation of MRT during pregnancy in only six adult female patients.

Malignant rhabdoid tumor of the liver: case report and literature review

A case of malignant rhabdoid tumor (MRT) occurring as a primary hepatic neoplasm in a 12-month-old Japanese female infant is presented. The patient had a slight fever for 2 weeks and presented with a palpable mass in her left hypochondrial region. After admission, the hepatic artery was embolized due to intra-abdominal hemorrhage arising from the tumor. The patient received chemotherapy with cisplatin, cyclophosphamide and adriacin. Despite treatment, the patient developed dyspnea, pancytopenia and disseminated intravascular coagulation. Rupture of the tumor resulted in death within 3 weeks. A limited abdominal autopsy revealed that the liver weighed 1240 g and was occupied by multiple hemorrhagic and/or necrotic tumor nodules. Histologically, neoplastic cells had an abundant eosinophilic cytoplasm containing paranuclear inclusions, and vesicular nuclei with a centrally located prominent nucleolus. Ultrastructurally, the cytoplasmic inclusions were composed of whorled filaments measuring 10 nm. Immunohistochemically, almost all of the neoplastic cells were positive for vimentin and cytokeratins (CK) 8 and 18, some were positive for CK 7 and 19, while none were positive for CK 1, 10, 13-17 and 20. The tumor cells did not express desmin, myoglobin, and alpha-fetoprotein. We found 18 cases of MRT of the liver published in English language literature and then, adding the present case, we summarized the 19 cases. Hepatic MRT is an uncommon neoplasm. However, it should be considered in the differential diagnosis of an aggressive liver neoplasm in childhood.

"Proximal-type" epithelioid sarcoma in a young girl

Epithelioid sarcoma is a rare, malignant soft-tissue neoplasm occurring on the distal extremities of young adults. Its histologic features consist of a proliferation of rounded to plump, spindle-shaped cells with abundant eosinophilic cytoplasm around areas of necrosis, simulating a granulomatous process. Recently a different type of epithelioid sarcoma has been described and named "proximal-type" epithelioid sarcoma. It is found mostly in the pelvic and perineal areas of young to middle-aged adults. On microscopic examination, the tumor is characterized by a proliferation of epithelioid-like cells with rhabdoid features in the absence of a granuloma-like pattern, and immunohistochemically it coexpresses vimentin, cytokeratin, epithelial membrane antigen, and CD34. As we found no report of proximal epithelioid sarcoma in the dermatologic literature, we describe an additional case in a 12-year-old girl. This type of tumor appears to be somewhat more aggressive than the classical, distal type and it should be considered in the differential diagnosis of tumors showing rhabdoid features, in particular extrarenal malignant rhabdoid tumor.

Epithelioid sarcoma: new insights based on an extended immunohistochemical analysis

CONTEXT

Epithelioid sarcoma has a distinctive epithelioid phenotype and characteristically exhibits immunohistochemical reactivity for epithelial markers (keratins and epithelial membrane antigen) and mesenchymal markers (most notably vimentin and CD34). Antibodies to certain keratin subunits and other novel antigens now available to surgical pathologists have not been tested on a large number of cases.

OBJECTIVE

To assist in the differential diagnosis of epithelioid sarcoma and to help elucidate its histogenesis through an expanded immunohistochemical profile.

DESIGN

Immunohistochemical testing with diverse antibodies was performed on 95 archived epithelioid sarcomas including 73 classic and 22 histologically variant subtypes retrieved from the files of the Armed Forces Institute of Pathology.

RESULTS

Immunohistochemical reactivity (number positive/number of cases tested [percent positive], frequency of staining) included keratin 14 (31/64 [48%], variable), gamma-catenin (35/74 [47%], variable), keratin 5/6 (10/33 [30%], focal), calretinin (8/40 [20%], focal), keratin 20 (11/71 [15%], focal), p63 (3/20 [15%], focal), whereas 9 invasive cutaneous squamous cell carcinomas showed strong p63 positivity, epithelial-specific antigen (10/74 [14%], variable), CD117/Kit (5/37 [14%], focal), keratin 15 (3/23 [13%], rare cell), mesothelin (2/64 [3%], rare cell), and CD10 (1/41 [2%], rare cell). No reactivity was observed for keratins 2, 5, and 10.

CONCLUSIONS

Diagnostically, p63 and keratin 5/6 distinguish cutaneous squamous cell carcinoma (positive) from epithelioid sarcoma (usually negative). No single immunomarker was able to distinguish the main 4 histologic subtypes of epithelioid sarcoma, indicating that they are all histogenetically related lesions. The limited expression of specific keratin subtypes used in our study supports the notion that epithelioid sarcoma is a mesenchymal neoplasm capable of partial epithelial transformation.

Cytokeratin 7 and 20 expression in epithelioid sarcoma

BACKGROUND

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor of uncertain histogenesis that arises predominantly in the extremities of young adults. Immunohistochemically, the neoplastic cells are typically positive for vimentin, low molecular weight cytokeratin (CAM5.2) and epithelial membrane antigen (EMA).

METHOD

We examined eight cases of ES from seven different patients. All cases were studied with immunohistochemistry for EMA, CAM5.2 (keratin 8 and 18), 34BE12 (keratins 1, 5, 10 and 14/15), cytokeratins 7 and 20 (CK7, CK20), and CD34.

RESULTS

The average patient age was 53 (range 43-76) and the male:female ratio was 5:2. The location was the upper extremity in five tumors, the lower extremity, the perineum, and the paraspinal soft tissue in one tumor each. All cases contained predominantly epithelioid cells, but spindle cells were also present in three cases. All cases contained areas of geographic necrosis. CAM5.2 was strongly positive in seven tumors and focally positive in one (8/8). EMA was diffusely positive in two cases and focally positive in five cases (7/8). CD34 was diffusely positive in 3/8 cases. 34BE12 was diffusely positive in one case and focally positive in two others (3/8). CK7 was diffusely positive in one case and focally positive in another (2/8). CK20 was negative in all cases (0/8). All cases tested were positive for vimentin (6/6), 2 cases were focally positive for HHF35 (2/5), and all cases tested were negative for S-100 protein (0/7).

CONCLUSIONS

In addition to the known immunoreactivity for CAM5.2 and EMA, there is positivity for CK7 and 34BE12 in a small proportion of cases. None of the cases expressed CK20. This immunophenotypic profile suggests that ES is more similar to carcinoma and synovial sarcoma than to other soft tissue tumors, and may be of diagnostic utility.

Matrix metalloproteinase-2 expression correlates with morphological and immunohistochemical epithelial characteristics in synovial sarcoma

AIMS

Synovial sarcoma is a unique mesenchymal tumour characterized by the presence of epithelial differentiation, although the mechanism involved in the epithelial morphology is still unclear. The aim of this study was to evaluate the function of matrix metalloproteinase-2 (MMP-2) in synovial sarcoma, in order to assess whether MMP-2 expression plays an important role in epithelial differentiation, or whether it contributes to a poor clinical outcome.

METHODS AND RESULTS

Immunohistochemical stainings for MMP-2, cytokeratins (CKs) 7, 8, 18 and 19, and E-cadherin were performed for 58 (44 monophasic and 14 biphasic) cases of synovial sarcoma, and we compared the expression of these proteins with the histological and clinical findings. MMP-2 and E-cadherin expression was observed in 43 cases (74.1%) and in 18 cases (31.0%), respectively. Expression of these proteins was preferentially observed in the glandular components of biphasic tumours or the epithelioid areas of monophasic tumours. Statistically significant correlations were recognized between MMP-2 expression and E-cadherin expression of biphasic subtype. Moreover, there were statistically significant correlations between monophasic tumours with epithelioid areas and MMP-2 expression or E-cadherin expression. MMP-2 expression was correlated with epithelial differentiation as assessed by CK immunoreactivity. The expression of MMP-2 did not affect the overall survival rate in synovial sarcoma.

CONCLUSIONS

MMP-2 expression seemed to have an important role to play in the epithelial differentiation of tumour cells in synovial sarcoma, through remodelling of the extracellular matrix and by changing the cytoskeletal interaction between the extracellular matrix and tumour cells.

Mutation analysis of human cytokeratin 8 gene in malignant rhabdoid tumor: a possible association with intracytoplasmic inclusion body formation

The rhabdoid cell, which is typically observed in malignant rhabdoid tumor (MRT) and other malignant neoplasms, has an eosinophilic cytoplasm containing a spheroid perinuclear inclusion body. This distinct cell is known to act as a highly aggressive indicator in many types of malignant tumors and is characterized by aggregates of intermediate filaments, comprising both vimentin and cytokeratin (CK) 8, which is mainly expressed in simple-type epithelium such as liver and intestine. To clarify the cause of the inclusion body formation, we analyzed the alteration of the complete human CK8 gene (KRT 8: 1724 base pairs) in seven samples of MRT (three from frozen materials and four from cultured cell lines) by reverse-transcriptase polymerase chain reaction, followed by direct sequencing. In addition, the two cell lines, Huh7 and HeLa, which lacked rhabdoid feature, six pediatric malignant tumors, including three cases of primitive neuroectodermal tumor (PNET) and three of Wilms' tumor; and 15 normal liver tissue (as a control) were also analyzed. All MRT samples had missense mutations in the human KRT 8 gene, i.e., Arg89 --> Cys (5/7); Arg --> Cys251 (3/7); Glu267 --> Lys (6/7); Ser290 --> Ile, Met; (7/7) and Arg301 --> His(4/7), none of which was detected in any control samples. Among these mutations, the most noteworthy findings were that Arg89 belongs to the H1 subdomain of the head domain and that Arg251 belongs to the short nonhelical linker segment, or L1-2. Both these mutations are noted for their relationships to lateral protofilament-protofilament interactions. In addition, Ser290 has been previously reported to be a phosphorylation site, which has been recognized to play an important role in filament organization, leading to conformational change of the CK8 filaments. In conclusion, mutated codons of CK8 gene in MRT were located in the important region involved in the conformational change of intermediate filament.

Subcellular distribution of cytokeratin and vimentin in malignant rhabdoid tumor: three-dimensional imaging with confocal laser scanning microscopy and double immunofluorescence

Malignant rhabdoid tumor (MRT) is a highly aggressive neoplasm that mostly occurs in childhood, characterized histologically by rhabdoid cells as shown by eosinophilic intracytoplasmic inclusions. Although it is known that rhabdoid cells co-express cytokeratin (CK) and vimentin, the distribution patterns of these two kinds of intermediate filaments and structural relationship between them are still not known. We investigated the subcellular distribution of CKs 8 and 18 and vimentin in MRT cell lines (Tm87-16, STM91-01, TTC549, and TC289) using confocal laser scanning microscopy and double immunofluorescence, in addition to ultrastructural examination. Vimentin was diffusely expressed in the cytoplasm of MRT cells, focally forming a filamentous network. In contrast, CKs 8 and 18 were partially expressed in the cytoplasm of MRT cells, forming globules or a few vague agglomerates. Three-dimensional images in TC289 cells revealed distinct distribution patterns of cytokeratin and vimentin, showing agglomerates of cytokeratins within the vimentin filament network. We conclude that these globules and agglomerates of CKs 8 and 18 correspond with the characteristic ultrastructural finding, showing cytoplasmic bundles of intermediate filaments concentrated in whorled arrays.