Histopathological re-classification of extremity pleomorphic soft tissue sarcoma has clinical relevance

Undifferentiated and dedifferentiated soft tissue neoplasms: Immunohistochemical surrogates for differential diagnosis

Undifferentiated soft tissue sarcomas (USTS) are described in the current World Health Organization Classification of Soft Tissue and Bone Tumours as those showing no identifiable line of differentiation when analyzed by presently available technologies. This is a markedly heterogeneous group, and the diagnosis of USTS remains one of exclusion. USTS can be divided into four morphologic subgroups: pleomorphic, spindle cell, round cell and epithelioid undifferentiated sarcomas, with this combined group accounting for up to 20% of all soft tissue sarcomas. As molecular advances enable the stratification of emerging genetic subsets within USTS, particularly within undifferentiated round cell sarcomas, other groups, particularly the category of undifferentiated pleomorphic sarcomas (UPS), still remain difficult to substratify and represent heterogeneous collections of neoplasms often representing the common morphologic endpoints of a variety of malignant tumors of various (mesenchymal and non-mesenchymal) lineages. However, recent molecular developments have also enabled the identification and correct classification of many tumors from various lines of differentiation that would previously have been bracketed under 'UPS'. This includes pleomorphic neoplasms and dedifferentiated neoplasms (the latter typically manifesting with an undifferentiated pleomorphic morphology) of mesenchymal (e.g. solitary fibrous tumor and gastrointestinal stromal tumor) and non-mesenchymal (e.g. melanoma and carcinoma) origin. The precise categorization of 'pleomorphic' or 'undifferentiated' neoplasms is critical for prognostication, as, for example, dedifferentiated liposarcoma typically behaves less aggressively than other pleomorphic sarcomas, and for management, including the potential for targeted therapies based on underlying recurrent molecular features. In this review we focus on undifferentiated and dedifferentiated pleomorphic and spindle cell neoplasms, summarizing their key genetic, morphologic and immunophenotypic features in the routine diagnostic setting, and the use of immunohistochemistry in their principal differential diagnosis, and highlight new developments and entities in the group of undifferentiated and dedifferentiated soft tissue sarcomas.

Prognostic Value of Myogenic Differentiation in Dedifferentiated Liposarcoma

Myogenic differentiation (MD) has been claimed to be a poor prognostic factor in dedifferentiated liposarcoma (DDLPS). To validate this, the prognostic significance of MD in a uniformly treated cohort of DDLPS was assessed. A cohort of patients that have been uniformly treated at one institution for DDLPS of the retroperitoneum and pelvis were stained with smooth muscle actin (SMA) and desmin and semiquantitatively scored for staining focality and strength. Clinical and survival data was collected, and the prognostic significance of MD was evaluated. A total of 50 patients with uniformly treated DDLPS were evaluated. SMA (P=0.052) and a combined score of MD (SMA+desmin) showed a statistically significant decrease in 5-year disease-free survival (P=0.002) in univariate analysis and in multivariate testing combined MD trended toward significance (P=0.052). Combined MD was associated with a decreased OS in multivariate analysis (P=0.004). In a uniformly treated cohort of DDLPS stained for myogenic markers, a combined myogenic score was associated with poor overall survival in multivariate analysis. However, the difference in groups was slight and the clinical application is limited.

Pleomorphic Sarcomas: The State of the Art

This article focuses on pleomorphic sarcomas, which are malignant mesenchymal tumors with complex genetic background at the root of their morphologic pleomorphism. They are poorly differentiated tumors that may retain different lines of differentiation, sometimes correlating with clinicopathological or prognostic features. Accurate diagnosis in this group of tumors relies on adequate sampling due to their heterogeneity and assessment with both microscopy and large panels of immunohistochemistry. Molecular analyses have a limited role in their diagnosis as opposed to translocation-related sarcomas but may provide theranostic and important prognostic information in the future.

Subclassification of pleomorphic sarcomas: How and why should we care?

Pleomorphic sarcomas are a heterogeneous group of mesenchymal neoplasms with widely varied clinical behavior but overlapping histologic appearances. The following guidelines are helpful when approaching the diagnosis of a pleomorphic sarcoma. (1) Be aware of the relative incidence of the various sarcoma types: several pleomorphic sarcomas are relatively common (e.g., dedifferentiated liposarcoma and undifferentiated pleomorphic sarcoma), whereas others are exceptionally rare. (2) Pay attention to anatomic location: some pleomorphic sarcomas have a predilection for somatic soft tissues, especially the thigh (e.g., undifferentiated pleomorphic sarcoma, pleomorphic liposarcoma, pleomorphic rhabdomyosarcoma), whereas other pleomorphic sarcomas most often arise in the retroperitoneum (e.g., dedifferentiated liposarcoma). (3) Carefully sample the resection specimen, paying particular attention to areas with differences in gross appearances (e.g., fleshy, fibrous, mucoid, or gritty). (4) Search for histologic clues (i.e., myxoid stroma, lipoblasts, and osteoid matrix, in order to diagnose myxofibrosarcoma, pleomorphic liposarcoma, and extraskeletal osteosarcoma, respectively); these critical diagnostic features may be limited in extent. (5) Apply immunohistochemistry judiciously, after generating a differential diagnosis; always exclude metastatic sarcomatoid carcinoma and melanoma before diagnosing a pleomorphic sarcoma. This review will present an approach to the diagnosis of pleomorphic sarcomas, emphasizing differential diagnosis and the application of ancillary studies (immunohistochemistry and FISH), when relevant.

Optimal Percent Myxoid Component to Predict Outcome in High-Grade Myxofibrosarcoma and Undifferentiated Pleomorphic Sarcoma

BACKGROUND

Myxofibrosarcoma and undifferentiated pleomorphic sarcoma (UPS) are aggressive, genetically complex sarcomas. The minimum myxoid component used as a criterion for myxofibrosarcoma varies widely, so we determined the optimal myxoid component cutpoints for stratifying outcomes of UPS and myxofibrosarcoma. We also analyzed clinicopathologic factors associated with outcome.

METHODS

Review of a prospective, single-institution database identified 197 patients with primary, high-grade extremity/truncal myxofibrosarcoma or UPS resected during 1992-2013. Histology was reviewed and percent myxoid component determined for each tumor. Disease-specific survival (DSS) and distant recurrence-free survival (DRFS) were analyzed using the Kaplan-Meier method, log-rank test, and Cox regression.

RESULTS

Median follow-up for survivors was 6.4 years. In minimum p value analysis of myxoid component, the best cutpoint for both DSS and DRFS was 5% (adjusted p ≤ 0.001), followed by 70%. Therefore, sarcomas with <5% myxoid component (n = 69) were classified as UPS and those with ≥5% myxoid component (n = 128) as myxofibrosarcoma. Five-year DRFS was 24% for UPS, 51% for 5-69% myxoid component myxofibrosarcoma, and 65% for ≥70% myxoid component myxofibrosarcoma. Myxoid component, tumor size, and age were independently associated with DSS; myxoid component and tumor size were associated with DRFS. Only tumor site was associated with local recurrence.

CONCLUSIONS

Percent myxoid component and tumor size are the two most important predictors of DSS and DRFS in high-grade myxofibrosarcoma and UPS. A 5% myxoid component cutpoint is an improved criterion for classifying myxofibrosarcoma. Myxoid component-based classification improves stratification of patient outcome and will aid in selection of patients for systemic therapy and clinical trials.

Evaluation of prognostic factors in localized high-grade undifferentiated pleomorphic sarcoma: report of a multi-institutional experience of Anatolian Society of Medical Oncology

Most data on prognostic factors for patients with high-grade undifferentiated pleomorphic sarcoma (HGUPS) is obtained from analyses of soft tissue sarcomas. The purpose of this study was to evaluate the clinicopathologic features and their impact on outcomes specifically in patients diagnosed with HGUPS. In this multicenter trial, we retrospectively analyzed 112 patients who were diagnosed and treated at 12 different institutions in Turkey. We collected data concerning the patients, tumor characteristics, and treatment modalities. There were 69 males (61.6 %) and 43 females (38.4 %). Median age was 56 years (19-90). The most common anatomic site of tumor origin was the upper extremity. Pleomorphic variant was the predominant histological subtype. Median tumor size was 8.2 cm (0.6-30 cm). Tumors were mainly deeply seated (57.1 %). Fifty-seven patients (50.9 %) were stage II and the remainder were stage III at the time of diagnosis. Median follow-up was 30 months (2-160). The primary site of distant metastasis was the lung (73.5 %) and the second most common site was the liver (11.7 %). The 5-year overall survival, distant metastasis-free survival, and local recurrence-free survival rates were 56.3, 53.4, and 67.2 %, respectively. Multivariate analysis showed that Eastern Cooperative Oncology Group (ECOG) performance score of II (p = 0.033), deep tumor location (p = 0.000), and development of distant metastasis (p = 0.004) were negatively correlated with overall survival, and perioperative radiotherapy and negative microscopic margins were significant factors for local control rates (p = 0.000 for each). Deep tumor location (p = 0.003) was the only adverse factor related to distant metastasis-free survival. Deep tumor location, ECOG performance score of II, and development of distant metastasis carry a poor prognostic implication on overall survival. These will aid clinicians in predicting survival and treatment decision.

Leiomyosarcoma with alternative lengthening of telomeres is associated with aggressive histologic features, loss of ATRX expression, and poor clinical outcome

Leiomyosarcoma is an aggressive soft tissue sarcoma with poor patient survival. Recently, it was shown that 53% to 62% of leiomyosarcomas use the alternative lengthening of telomeres (ALT) as their telomere maintenance mechanism. The molecular basis of this mechanism has not been elucidated. Studies of pancreatic neuroendocrine tumor have suggested that the inactivation of either α-thalassemia/mental retardation syndrome X-linked (ATRX) or death domain-associated (DAXX) protein is associated with the ALT phenotype. In this study, we sought to determine the clinicopathologic features of leiomyosarcoma with the ALT phenotype and the possible relationship between this phenotype and ATRX/DAXX expression. Telomerase reverse transcriptase gene (TERT) promoter mutation analysis was also performed. Ninety-two leiomyosarcomas derived from the uterus, retroperitoneum/intra-abdomen, and various other sites were analyzed. Telomere-specific fluorescence in situ hybridization revealed that 59% (51/86) of leiomyosarcomas had the ALT phenotype. Loss of ATRX expression was observed in 33% of the tumors (30/92), and all but 2 ATRX-deficient tumors were ALT positive. Both the ALT phenotype and loss of ATRX expression were associated with epithelioid/pleomorphic cell morphology, tumor necrosis, and poor differentiation. None of the 92 cases lost DAXX expression. No TERT promoter mutation was detected (n=39). For survival analysis, poor differentiation, high FNCLCC grade, tumor size, and ALT phenotype were correlated with poor overall survival in univariate analysis. Tumor size and ALT phenotype remained independent prognostic factors in multivariate analysis. We concluded that the ALT phenotype in the leiomyosarcoma is associated with aggressive histologic features, loss of ATRX expression, and poor clinical outcome.

Progressive loss of myogenic differentiation in leiomyosarcoma has prognostic value

AIMS

Well-differentiated leiomyosarcomas show morphologically recognizable smooth muscle differentiation, whereas poorly differentiated tumours may form a spectrum with a subset of undifferentiated pleomorphic sarcomas. The expression of certain muscle markers has been reported to have prognostic impact. We investigated the correlation between the morphological spectrum and the muscle marker expression profile of leiomyosarcoma, and the impact of these factors on patient outcomes.

METHODS AND RESULTS

Tissue microarrays including 202 non-uterine and 181 uterine leiomyosarcomas with a spectrum of tumour morphologies were evaluated for expression of immunohistochemical markers of muscle differentiation. Poorly differentiated tumours frequently lost one or more conventional smooth muscle markers [smooth muscle actin, desmin, h-caldesmon, and smooth muscle myosin (P < 0.0001)], as well as the more recently described markers SLMAP, MYLK, and ACTG2 (P < 0.0001). In primary tumours, both desmin and CFL2 expression predicted improved overall survival in multivariate analyses (P = 0.0111 and P = 0.043, respectively). Patients with muscle marker-enriched tumours (expressing all four conventional markers or any three of ACTG2, CFL2, CASQ2, MYLK, and SLMAP) had improved overall survival (P < 0.05) in univariate analyses.

CONCLUSIONS

Morphologically and immunohistochemically, poorly differentiated leiomyosarcomas can masquerade as undifferentiated pleomorphic sarcomas with progressive loss of muscle markers. The expression of muscle markers has prognostic significance in primary leiomyosarcomas independently of tumour morphology.

An approach to pleomorphic sarcomas: can we subclassify, and does it matter?

The term malignant fibrous histiocytoma (MFH) has been supplanted by undifferentiated pleomorphic sarcoma (UPS). Even now, however, a number of pleomorphic neoplasms are classified as UPSs when in fact at least a subgroup of these can be more precisely classified as a pleomorphic sarcoma with a specific line of differentiation. Still others are pseudosarcomas, most commonly sarcomatoid carcinomas. This review will discuss historical aspects of MFH/UPS as well as provide an approach to the pleomorphic malignant neoplasm with a discussion of useful ancillary techniques in the evaluation of such cases.

Amplification of FRS2 and activation of FGFR/FRS2 signaling pathway in high-grade liposarcoma

Fibroblast growth factor (FGF) receptor (FGFR) substrate 2 (FRS2) is an adaptor protein that plays a critical role in FGFR signaling. FRS2 is located on chromosome 12q13-15 that is frequently amplified in liposarcomas. The significance of FRS2 and FGFR signaling in high-grade liposarcomas is unknown. Herein, we first comparatively examined the amplification and expression of FRS2 with CDK4 and MDM2 in dedifferentiated liposarcoma (DDLS) and undifferentiated high-grade pleomorphic sarcoma (UHGPS). Amplification and expression of the three genes were identified in 90% to 100% (9-11 of 11) of DDLS, whereas that of FRS2, CDK4, and MDM2 were observed in 55% (41 of 75), 48% (36 of 75), and 44% (33/75) of clinically diagnosed UHGPS, suggesting that these "UHGPS" may represent DDLS despite lacking histologic evidence of lipoblasts. Immunohistochemical analysis of phosphorylated FRS2 protein indicated that the FGFR/FRS2 signaling axis was generally activated in about 75% of FRS2-positive high-grade liposarcomas. Moreover, we found that FRS2 and FGFRs proteins are highly expressed and functional in three high-grade liposarcoma cell lines: FU-DDLS-1, LiSa-2, and SW872. Importantly, the FGFR selective inhibitor NVP-BGJ-398 significantly inhibited the growth of FU-DDLS-1 and LiSa-2 cells with a concomitant suppression of FGFR signal transduction. Attenuation of FRS2 protein in FU-DDLS-1 and LiSa-2 cell lines decreased the phosphorylated extracellular signal-regulated kinase 1/2 and AKT and repressed cell proliferation. These findings indicate that analysis of FRS2 in combination with CDK4 and MDM2 will more accurately characterize pathologic features of high-grade liposarcomas. Activated FGFR/FRS2 signaling may play a functional role in the development of high-grade liposarcomas, therefore, serve as a potential therapeutic target.

Immunohistochemistry in diagnosis of soft tissue tumours

Immunohistochemistry in soft tissue tumours, and especially sarcomas, is used to identify differentiation in the neoplastic cells. In some cases, specific antigens are expressed; however, an initial panel of antibodies is often required in order to establish the broad lineage, with a subsequent, more focused, panel to allow classification. Immunohistochemical evaluation must be employed with the clinical picture, the morphology, and, when necessary, other ancillary techniques such as molecular genetics and cytogenetics. Whereas some diagnoses are evident on morphology, many soft tissue neoplasms are seen microscopically as spindle cell, epithelioid cell, small round cell or pleomorphic tumours that need to be further characterized. This article reviews selected applications of immunohistochemistry in the diagnosis of each of the principal morphological groups, concentrating on areas of most use in daily practice.

The impact of re-excision of inadequately resected soft tissue sarcomas on surgical therapy, results, and prognosis: A single institution experience with 682 patients

BACKGROUND AND OBJECTIVES

Due to their rare incidence soft tissue sarcomas (STS) are often resected without clear margins. The aim of this study was to investigate the impact of re-excision of STS on survival.

METHODS

Out of 752 patients with STS (406 men and 346 women, average age 51 years), 310 patients were referred after an inadequate resection, 442 patients presented for primary treatment. Six hundred eighty-two patients were compared over a mean period of 65 months (median, 36 months) according to the treatment groups regarding their survival, clinical, surgical, and pathological data.

RESULTS

The 5-year survival rate of 621 surgically treated patients was 53.9%. There was a continuous improvement in survival during the whole treatment period in the respective decades. The overall survival rate in both groups was not significantly different regardless of low- or high-grade malignancies. Patients with a re-resection did not have a higher rate of local recurrences; patients with a primary resection had a worse prognosis regarding metastases. A re-resection within 12 weeks indicated a better prognosis.

CONCLUSIONS

An inadequate excision of a STS does not cogently mean deterioration of overall survival but necessitates an ample and quick re-resection.

Undifferentiated high-grade pleomorphic sarcoma in a California sea lion (Zalophus californianus)

A tumour located in the pectoral region and the left front flipper was observed in a 29-year-old female California sea lion (Zalophus californianus) that died following signs of respiratory disease and inappetence. Metastases were present in the lung and adrenal gland. The histological pattern of the tumour was variable. In some areas the tumour consisted of pleomorphic fibroblast-like cells arranged in a storiform pattern, while in other areas it comprised oval or polygonal cells with round to oval nuclei and some bizarre cells arranged in an alveolar pattern. Occasionally, multinucleated giant cells were observed. Immunohistochemically, the neoplastic cells only expressed vimentin. On the basis of the microscopical and immunohistochemical features the tumour was diagnosed as an undifferentiated high-grade pleomorphic sarcoma. This type of neoplasm with disseminated involvement of other organs is rare in all species and has never been reported in California sea lions.

Added Value of Molecular Biological Analysis in Diagnosis and Clinical Management of Liposarcoma: A 30-Year Single-Institution Experience

Background

Treatment decisions and prognosis assessment for liposarcoma is based on a classification that depends on morphological and genetic features. Revisions by experienced referral pathologists are often advocated.

Methods

The process of histopathological classification in referring hospitals and subsequently in a referral center in relation to molecular biological information is evaluated. A total of 331 consecutive liposarcoma patients were evaluated for the added value of histological review at time of referral. Subsequently, cases were reclassified with implementation of present-day molecular information. For all patients, complete data on staging, treatment, and follow-up were available.

Results

Upon histological revision, 15/54 (28%) diagnoses were reclassified in the first decade, 14/65 (22%) in the second, and 14/53 (26%) in the last decade. Molecular biological analysis enabled well-differentiated liposarcoma with or without dedifferentiated component to be better recognized as such and distinguished from myxoid liposarcoma and pleomorphic liposarcoma. Inclusion of cytogenetic information resulted in reclassification after revision in 4/18 (22%) cases in the first decade, 10/38 (26%) cases in the second decade, and 19/75 (25%) cases in the last decade.

Conclusions

This study indicates that liposarcomas are heterogeneous tumors. Expert assessment and implementation of molecular biological analysis are valuable for adequate classification as a basis for treatment decisions.

Malignant fibrous histiocytoma--pleomorphic sarcoma, NOS gene expression, histology, and clinical course. A pilot study

PURPOSE

The new classification of malignant fibrous histiocytoma leaves only a small group of tumors without further line of differentiation, so-called pleomorphic sarcomas, not otherwise specified (NOS) as a pseudo-entity. This study focused on these tumors and analyzed the association of gene expression profiles to clinical outcome.

MATERIALS AND METHODS

Ten fresh samples of pleomorphic NOS sarcomas were evaluated histopathologically and by means of microarray analysis. Analysis of expression profiles was performed by clustering methods as well as by statistical analysis of primary vs recurrent tumors, irradiated vs nonirradiated tumors, tumors of patients above and below 60 years of age, male and female, and of tumors that developed metastatic or recurrent disease during the clinical course and those that did not.

RESULTS

Tumor clustering did not correlate to any histopathological or clinical finding. Detailed gene expression analysis showed a variety of genes whose upregulation (platelet-derived growth factor receptor alpha polypeptide, solute carrier family 39 member 14, solute carrier family 2 member 3, pleiotrophin, trophinin, pleckstrin and Sec7 domain containing 3, enolase 2, biglycan, SH3 and cysteine-rich domain, matrix metalloproteinases 16) and whose downregulation (tissue inhibitor of metalloproteinase 4, hairy/enhancer of split related with YRPW motif 2, protein tyrosine phosphatase receptor-type Z polypeptide 1, SH3 domain GRB2-like 2, microtubule-associated protein 7, potassium voltage-gated channel shaker-related subfamily member 1, RUN and FYVE domain containing 3, Sin3A-associated protein 18 kDa, proline-rich 4, calcium/calmodulin-dependent protein kinase ID, myeloid/lymphoid or mixed-lineage leukemia translocated to 3, insulin-like growth factor binding protein 5, nucleoside diphosphate-linked moiety X-type motif 9, NudC domain containing 3, imprinted in Prader-Willi syndrome, TAF6-like RNA polymerase II p300/CBP-associated factor 65 kDa, WD repeat and SOCS box-containing 2, adenosine diphosphate ribosylation factor 3, KRR1, proliferation-associated 2G4; CD36, complement component (3b/4b) receptor 1, solute carrier family 4 sodium bicarbonate cotransporter member 4, lipoprotein lipase (LPL), GATA binding protein 3, LPL, glutathione peroxidase 3, D: -aspartate oxidase, apolipoprotein E, sphingomyelin phosphodiesterase acid-like 3A) were associated with poor clinical outcome in terms of development of metastatic or recurrent disease.

CONCLUSIONS

The classification of these tumors may undergo further changes in the future. Gene expression profiling can provide additional information to categorize pleomorphic sarcoma (NOS) and reveal potential prognostic factors in this "entity."

Molecular classification of rhabdomyosarcoma--genotypic and phenotypic determinants of diagnosis: a report from the Children's Oncology Group

Rhabdomyosarcoma (RMS) in children occurs as two major histological subtypes, embryonal (ERMS) and alveolar (ARMS). ERMS is associated with an 11p15.5 loss of heterozygosity (LOH) and may be confused with nonmyogenic, non-RMS soft tissue sarcomas. ARMS expresses the product of a genomic translocation that fuses FOXO1 (FKHR) with either PAX3 or PAX7 (P-F); however, at least 25% of cases lack these translocations. Here, we describe a genomic-based classification scheme that is derived from the combined gene expression profiling and LOH analysis of 160 cases of RMS and non-RMS soft tissue sarcomas that is at variance with conventional histopathological schemes. We found that gene expression profiles and patterns of LOH of ARMS cases lacking P-F translocations are indistinguishable from conventional ERMS cases. A subset of tumors that has been histologically classified as RMS lack myogenic gene expression. However, classification based on gene expression is possible using as few as five genes with an estimated error rate of less than 5%. Using immunohistochemistry, we characterized two markers, HMGA2 and TFAP2ss, which facilitate the differential diagnoses of ERMS and P-F RMS, respectively, using clinical material. These objectively derived molecular classes are based solely on genomic analysis at the time of diagnosis and are highly reproducible. Adoption of these molecular criteria may offer a more clinically relevant diagnostic scheme, thus potentially improving patient management and therapeutic RMS outcomes.

Application of immunohistochemistry to soft tissue neoplasms

CONTEXT

Soft tissue tumors are composed of numerous and complex diagnostic entities. Because of this complexity and the recognition of an intermediate malignancy category including some tumors with a deceptively bland histologic appearance, soft tissue tumors may represent a major diagnostic challenge to the general practicing pathologist.

OBJECTIVE

To correctly diagnose soft tissue tumors with the ancillary use of immunohistochemistry.

DATA SOURCES

Review of the current literature with emphasis on those tumors for which immunohistochemistry has proven to be particularly useful.

CONCLUSIONS

Immunohistochemistry plays an important role in the diagnosis of soft tissue tumors. One of its major utilities is to correctly identify a tumor as being of mesenchymal or nonmesenchymal origin. Once mesenchymal origin has been established, histologic subtyping according to specific cell lineage may be achieved with the use of lineage-specific markers. Tumors of uncertain cell lineage and tumors with primitive small round cell morphology are often characterized by a unique immunohistochemical phenotype. In this group of tumors, immunohistochemistry is most widely applied and is of greatest value. Despite the rapid development of molecular genetic techniques, immunohistochemistry still remains the most important diagnostic tool in the diagnosis of soft tissue tumors aside from recognition of morphologic features and clinical correlation.

Oral undifferentiated high-grade pleomorphic sarcoma: report of a case

The current World Health Organization classification considers the existence of an undifferentiated unclassifiable category of pleomorphic sarcomas, defined as a group of pleomorphic high-grade sarcomas. Undifferentiated high-grade pleomorphic sarcoma represents about 5% of all soft tissue sarcomas in adults and occurs more commonly in the extremities. In the oral cavity, undifferentiated pleomorphic sarcoma is extremely rare. We report a case of undifferentiated high-grade pleomorphic sarcoma located in the floor of the mouth in a man 56 years old. Microscopically, spindle-shaped cells with accented pleomorphism arranged in a storiform pattern, several bizarre giant cells, and frequent atypical mitoses were observed. The tumor cells were positive only for vimentin, with focal positivity for CD68. The patient was treated by surgery and postoperative radiation therapy, and after 25 months, no recurrence was observed.

Primary and metastatic high-grade pleomorphic sarcoma/malignant fibrous histiocytoma of the gastrointestinal tract: an approach to the differential diagnosis in a series of five cases with emphasis on myofibroblastic differentiation

Primary and metastatic so-called malignant fibrous histiocytoma/undifferentiated high-grade pleomorphic sarcoma (MFH) is rare in the gastrointestinal (GI) tract with approximately 50 primary and five metastatic cases reported so far. We evaluated two primary gastric and three metastatic intestinal high-grade pleomorphic sarcomas with features of storiform-pleomorphic MFH. Gastric tumours occurred in a 79-year-old man and a 68-year-old woman. One patient died post-operatively, and the other was disease-free at 6 months. Three patients presented with GI metastasis 24, 60 and 0 months after diagnosis of MFH of the heart (n = 1) and the thigh (n = 2). Metastases were located in the small (n = 1) and large bowel (n = 2) and were characteristically pedunculated and polypoid with oedematous haemorrhagic stroma. Concurrent metastases (brain, lung, bone) were present in all three cases. Tumours expressed alpha-smooth muscle actin (four of five), platelet-derived growth factor receptor (PDGFR) alpha (three of three) and PDGFRbeta (two of three) but were negative for CD117, CD34 and other lineage-specific markers. Ultrastructural examination revealed myo/fibroblastic features. Both gastric MFH were wild type for KIT and PDGFRalpha. In conclusion, primary and metastatic MFH of the GI tract commonly express PDGFRalpha and show a myo/fibroblastic phenotype. They should be distinguished from a variety of primary and metastatic pleomorphic neoplasms, in particular high-grade sarcomatous GI stromal tumours (GIST), pleomorphic leiomyosarcoma, sarcomatoid carcinoma and other mimics.

Outcomes for Soft-Tissue Sarcoma in 8249 Cases from a Large State Cancer Registry

BACKGROUND AND OBJECTIVES

To date, outcome reports for soft-tissue sarcoma (STS) have largely been limited to single or paired institutional series. To more accurately elucidate population-based outcomes and prognostic factors associated with STS, a large cancer registry was examined.

METHODS

STS arising in the Florida Cancer Data System were examined (1981-2004).

RESULTS

A total of 8249 patients were identified, the calculated annual incidence of sarcoma being approximately 38 cases per million in 2003. The tumor histologies among these patients were leiomyosarcoma and gastrointestinal stromal tumor (LMS/GIST) (43.5%), malignant fibrous histiocytoma (MFH) (31.5%), liposarcoma (19.0%), and fibrosarcoma (6.0%). Tumors were situated in the extremities (30.7%), truncal or visceral locations (50.4%), retroperitoneum (11.7%), and head or neck (7.2%). Thirty-three percent of lesions were over 10 cm in greatest dimension, while 50.2% were classified as high grade. Median overall survival was 25 months. Superior survival was observed for liposarcomas and fibrosarcomas as compared to MFH and LMS/GIST (P < 0.001). Retroperitoneal and truncal sarcomas had a more ominous prognosis than did other sites (P < 0.001). Multivariate analysis of pretreatment variables demonstrated that increasing age, male gender, non-Caucasian race, advanced stage, and a truncal or retroperitoneal location were each independently associated with lower survival. Histological subtype was also an independent predictor of outcome. Surgical resection and radiation therapy were the only treatment variables shown to improve survival.

CONCLUSIONS

Histological subtype, tumor site, and stage are independent prognostic factors in STS. Surgical resection and radiotherapy are unique among treatment modalities in association with a significant survival benefit.

[Diagnosis and treatment of soft-tissue tumors]

The diagnostic and therapeutic management of patients with soft-tissue tumors would be similar to the approach used for bone tumors if it were not for one crucial factor: the absolute necessity to recognize a sarcoma. The predominant features are the size of the tumor and its superficial or deep localization. If the tumor is small and superficial, biopsy can be associated with immediate resection without risk of dissemination to the deep tissues: this is the biopsy-resection approach. If the tumor is deep or superficial but large sized, search for locoregional spread with MRI is necessary before undertaking any surgical procedure. MRI can help guide the biopsy and plan resection if the tumor is a sarcoma. A first biopsy is necessary to establish the histological diagnosis and elaborate the therapeutic strategy. Samples should be sent immediately to the pathology lab which should examine sterile fresh tissue. Experience has demonstrated that proper rules for diagnosis and treatment are not necessarily applied initially in approximately one-fourth of all subjects with a malignant soft-tissue tumor. Besides the medical problems caused by this situation, the patient loses a chance for cure. When the tumor is a sarcoma, surgery is the basis of treatment. Complementary radiation therapy may be necessary, particularly for high-grade tumors or if the surgical margin was insufficient. Systemic or locoregional chemotherapy can also be used for high-grade or non-resectable tumors.

Retroperitoneal and Truncal Sarcomas: Prognosis Depends Upon Type Not Location

BACKGROUND

Prognostication of truncal and retroperitoneal soft tissue sarcomas has traditionally been predicated on tumor location and grade.

OBJECTIVE

To compare outcomes for patients with retroperitoneal or truncal sarcomas.

METHODS

Retrospective analysis of a prospective cancer data registry from 1977 to 2004 was performed and outcomes were determined.

RESULTS

The study group numbered 312 patients (median age 58 years, 54% male, 56% Caucasian, 14% black, 29% Hispanic). The most common tumor types were liposarcoma (35.9%), leiomyosarcoma (30.1%), and malignant fibrous histiocytoma (MFH) (19.5%). Tumor distributions were retroperitoneal (38.9%), pelvic (24.7%), abdominal (18.6%) and thoracic (17.9%). Median overall survival was 74 months. Operative resection was undertaken in 89.4% of cases and multiple surgeries (range 2-5) in 42.2%. Negative resection margins were obtained in 72.7% of patients. Univariate analysis comparing retroperitoneal versus truncal location demonstrated no significant differences in survival. Survival was improved in lower grade tumors (P < 0.02). Liposarcoma and fibrosarcoma were associated with improved survival (P < 0.0001). Multivariate analysis of pre-treatment variables showed increasing age, grade, histopathology (leiomyosarcoma and MFH) and metastasis to be associated with worse outcomes. Multivariate analysis of the treatment variables showed that surgery and negative resection margins were associated with improved survival (P < 0.001). No advantage for chemoradiotherapy could be demonstrated.

CONCLUSIONS

Successful operative resection can confer prolonged disease-free survival and cure for truncal and retroperitoneal sarcomas. Histological subtype, not location, is predictive of long-term survival. Future studies should focus on histological subtype rather than tumor location for truncal and retroperitoneal sarcomas.

Classification of pleomorphic sarcomas: where are we now?

Until a decade ago, so-called pleomorphic and storiform malignant fibrous histiocytoma (MFH) represented the most frequently diagnosed sarcoma, accounting for approximately 40% of adult mesenchymal malignancies. However, the latest World Health Organization classification of soft tissue tumours considers MFH a synonym for undifferentiated pleomorphic sarcoma. Historically, the term MFH was introduced in the medical literature in 1963 by Ozzello, O'Brien and Stout, on the basis of the acquisition of phagocytic properties observed in cultured fibroblasts. The existence of MFH as a well-defined clinicopathological entity became rapidly very popular and by the mid 1980s MFH represented the most common sarcoma in adults. With the advent of electron microscopy, immunohistochemistry and molecular genetics, it became clear that the so-called "facultative fibroblast" theory had no scientific grounds and, in 1992, a milestone paper eventually brought attention to the concept that MFH merely represented a morphological pattern shared by a wide variety of poorly differentiated malignant neoplasms, which include specific subtypes of pleomorphic sarcomas. Currently, accurate subclassification of pleomorphic sarcomas is mandatory as it enables recognition of non-sarcomatous lesions as well as pleomorphic neoplasms not associated with aggressive behaviour. Furthermore, as myogenic differentiation predicts aggressive clinical behaviour among pleomorphic sarcomas, precise histotyping allows prognostic stratification of patients.