Low grade fibromyxoid sarcoma. a further low-grade soft tissue malignancy characterized by a ring chromosome

Bilateral Cleft Lip and Palate in Ring Chromosome 7 Syndrome: A Case Report and Review of Clinical Characteristics

This report presents a case of ring chromosome 7 syndrome with bilateral cleft lip and palate. A four-year-old boy presented with bilateral cleft lip and palate, microcephaly, clenched toes, cafe-au-lait spots, a history of epilepsy, and severe intellectual disability. Genetic karyotyping revealed 46 XY r(7) (p22q36). His cheiloplasty and delayed palatoplasty were successful. A review of 22 previous r(7) patients revealed that 22.7% had cleft lip and/or palate. This case demonstrates the importance of a multidisciplinary evaluation for cleft patients, particularly those with syndromic features and global developmental delay.

Primary lung low-grade fibromyxoid sarcoma: A rare case with A diagnostic dilemma

Low-grade fibromyxoid sarcoma (LGFMS) is a rare, low-grade malignant soft tissue tumor that is often mistaken for benign or more rarely malignant tumor types. Commonly, this tumor affects young adults and typically arises in the deep proximal extremities or trunk with frequent recurrences and can metastasize to the lungs many years late. Visceral LGFMS is extremely rare. Only a few cases of primary LGFMS of the lung have been reported. Here, we present the clinical, gross, microscopic, and immunohistochemical characteristics of Evans tumor occurring in the lung with a review of the literature and discuss the differential diagnosis in this exceptional localization.

A group of sclerosing epithelioid fibrosarcomas with low-level amplified EWSR1-CREB3L1 fusion gene in children

Sclerosing epithelioid fibrosarcoma (SEF), typically arising in middle-aged and older adults, is a rare malignant fibroblastic neoplasm characterized by epithelioid fibroblasts embedded in sclerotic hyalinized stroma. This tumor frequently harbors translocation between EWSR1 and CREB3 subfamily members. Here, we describe four cases of SEF with unique genetic characteristics in children. All tumors were located in the deep soft tissue of the trunk and celom. Histopathologically, the tumors were featured by prominent hyalinized sclerotic collagenous stroma within which relatively bland and monomorphic epithelioid cells were arranged in cords, nests, or sheets. Low-grade fibromyxoid sarcoma-like zones varied among cases. MUC4 was strong and diffuse. CD99 was positive. Transmission electron microscopy demonstrated spindle or polyhedral neoplastic cells with a collagen fiber-rich stroma. Interphase fluorescence in situ hybridization (FISH) revealed local amplification of the EWSR1 locus. Whole-genome sequencing indicated translocation between EWSR1 and CREB3L1 together with low-level amplification of the fusion parts. RT-PCR and Sanger sequencing confirmed the fusion transcript. Single nucleotide polymorphism and FISH analyses demonstrated co-deletion of 11p and 22q. The consistent genetic features indicated the presence of a unique molecular variant of SEF. DATA AVAILABILITY STATEMENT: The data used to support the findings of this study are available from the corresponding author upon request.

Rapidly enlarging low-grade fibromyxoid sarcoma with intracranial extension in a 5-year-old girl: case report

Low-grade fibromyxoid sarcoma (LGFMS) is a rare mesenchymal tumor that is characterized by a benign histology but potentially aggressive clinical behavior, with a high rate of recurrence and metastasis. It primarily occurs in young adults in the extremities, inguinal area, neck, or chest wall. There are rare reports of intracranial LGFMS in adults. In this report, the authors present the case of a 5-year-old girl who presented with a rapidly enlarging frontal scalp mass. Pathological examination of the resected mass demonstrated LGFMS. To the authors' knowledge, this is the only reported case of intracranial LGFMS in a child.

Low-Grade Fibromyxoid Sarcoma of the Head and Neck: A Clinicopathologic Series and Review of the Literature

Low-grade fibromyxoid sarcoma (LGFMS) is a deceptively bland malignancy with potential for late recurrence and metastasis, which usually occurs in the deep soft tissues of the extremities and trunk. Most LGFMSs harbor a characteristic gene fusion of FUS-CREB3L2, and recently MUC4 immunostaining has been found to be highly sensitive and specific for the diagnosis. We present a dedicated series of head and neck LGFMS, including the first reported laryngeal case, as well as a review of reported head and neck cases. The surgical pathology archives of our three institutions were searched for cases of LGFMS arising within the head and neck, and four cases were identified. The H&E slides were reviewed, and immunohistochemistry were performed for pancytokeratin, p63, p40, EMA, S100 protein, β-catenin, actin, CD34, and MUC4. The patients were 6, 43, 45, and 73 years old (mean 41.8 years) and included three males and one female. The tumors were located in the posterior cervical spine, facial skin, mandible, and larynx. The tumors were treated with surgical excision, and all four had histologic features typical for LGFMS including alternating myxoid and fibrous areas with prominent curvilinear vasculature. All tumors were MUC4 positive (100%), 2/4 (50%) were p63 positive, 1/4 (25%) showed focal EMA positivity; all 4 were negative for pancytokeratin, p40, S100 protein, β-catenin, actin, and CD34. LGFMS is a low grade sarcoma that rarely develops in the head and neck. Due to its rarity, a pathologist may not consider LGFMS in the differential diagnosis of spindle cell neoplasms within the head and neck. Immunohistochemical staining is helpful, but stains should be selected carefully to avoid misdiagnosis.

Molecular diagnostics in soft tissue sarcomas and gastrointestinal stromal tumors

Soft tissue sarcomas are rare malignant heterogenous tumors of mesenchymal origin with over fifty subtypes. The use of hematoxylin and eosin stained sections (and immunohistochemistry) in the morphologic assessment of these tumors has been the bane of clinical diagnosis until recently. The last decade has witnessed considerable progress in the understanding and application of molecular techniques in refining the current understanding of soft tissue sarcomas and gastrointestinal stromal tumors beyond the limits of traditional approaches. Indeed, the identification of reciprocal chromosomal translocations and fusion genes in some subsets of sarcomas with potential implications in the pathogenesis, diagnosis and treatment has been revolutionary. The era of molecular targeted therapy presents a platform that continues to drive biomarker discovery and personalized medicine in soft tissue sarcomas and gastrointestinal stromal tumors. In this review, we highlight how the different molecular techniques have enhanced the diagnosis of these tumors with prognostic and therapeutic implications.

Fibrosarcoma: a review and update

Adult fibrosarcoma, defined by the World Health Organization as a 'malignant neoplasm composed of fibroblasts with variable collagen production and, in classical cases, a "herringbone" architecture', is a very rare soft tissue sarcoma. Once considered the most common adult sarcoma, the incidence of adult fibrosarcoma has declined dramatically over the past several decades. This is due to (i) evolution in the classification of soft tissue tumours (ii) recognition of clinically, morphologically and genetically distinctive subtypes of fibrosarcoma and (iii) increased understanding of the many other mesenchymal and non-mesenchymal tumours that may mimic fibrosarcoma. This review article will summarize the current state of our knowledge about strictly defined adult fibrosarcoma and discuss important entities in its differential diagnosis, including various fibrosarcoma variants, monophasic synovial sarcoma and other potential mesenchymal and non-mesenchymal mimics.

Molecular Pathology of Sarcoma

The rapid growth of tissue-based molecular pathology has changed the practice of the surgical pathologist signing out soft tissue tumors. This information is presented in a practical and succinct manner focusing on clinically validated findings that have diagnostic or therapeutic relevance. The approach is morphologically based and focuses on differential diagnoses and clinical scenarios. Molecular techniques can be an invaluable ancillary tool.

Cytogenetics and molecular genetics of myxoid soft-tissue sarcomas

Myxoid soft-tissue sarcomas represent a heterogeneous group of mesenchymal tumors characterized by a predominantly myxoid matrix, including myxoid liposarcoma (MLS), low-grade fibromyxoid sarcoma (LGFMS), extraskeletal myxoid chondrosarcoma (EMC), myxofibrosarcoma, myxoinflammatory fibroblastic sarcoma (MIFS), and myxoid dermatofibrosarcoma protuberans (DFSP). Cytogenetic and molecular genetic analyses have shown that many of these sarcomas are characterized by recurrent chromosomal translocations resulting in highly specific fusion genes (e.g., FUS-DDIT3 in MLS, FUS-CREB3L2 in LGFMS, EWSR1-NR4A3 in EMC, and COL1A1-PDGFB in myxoid DFSP). Moreover, recent molecular analysis has demonstrated a translocation t(1; 10)(p22; q24) resulting in transcriptional upregulation of FGF8 and NPM3 in MIFS. Most recently, the presence of TGFBR3 and MGEA5 rearrangements has been identified in a subset of MIFS. These genetic alterations can be utilized as an adjunct in diagnostically challenging cases. In contrast, most myxofibrosarcomas have complex karyotypes lacking specific genetic alterations. This paper focuses on the cytogenetic and molecular genetic findings of myxoid soft-tissue sarcomas as well as their clinicopathological characteristics.

Fusion of the FUS and CREB3L2 genes in a supernumerary ring chromosome in low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma (LGFMS) is a rare, low-grade malignant soft tissue tumor that is often mistaken for either benign or more malignant tumor types. Commonly, this tumor affects young adults and typically arises in the deep proximal extremities or trunk with frequent recurrences and can metastasize to the lungs many years later. Most cases have a recurrent balanced translocation involving chromosomes 7 and 16, t(7;16)(q32-34;p11), which leads to the fusion of the FUS and CREB3L2 genes. However, supernumerary ring chromosomes have been identified in a subset of FUS/CREB3L2-positive LGFMS, but it has not yet been formally demonstrated that such ring chromosomes harbor the FUS/CREB3L2 fusion gene. Here, we report the genetic findings of a supernumerary ring chromosome from an LGFMS from a 77-year-old man. Chromosome banding analysis revealed a supernumerary ring chromosome, and further studies with fluorescence in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR) showed that the ring contained material from chromosomes 7 and 16, that the FUS gene was present in two rearranged copies, and that it expressed the FUS/CREB3L2 fusion gene. Moreover, an assessment of previously reported cases showed that tumors with ring chromosomes relapsed more often than tumors with a balanced t(7;16), suggesting that ring formation in LGFMS is correlated with tumor progression.

Low-grade fibromyxoid sarcoma of the medial vastus: a case report

Low-grade fibromyxoid sarcoma (LGFMS) was first described by Evans in 1987, and since then, just over 150 cases have been reported, showing the rarity of this tumor. We report the clinical case of a 56-year-old man with a swelling on the distal third of the left thigh. The mass had grown in the course of 1 year and was surgically excised, obtaining complete resolution. Immuno-histological examination demonstrated the lesion to be a LGFMS, defined as a benign tumor but with a high incidence of local and distant recurrence (5-10%). At 2-year follow-up the patient was disease-free, confirming the efficacy of the surgical excision. In literature, the frequency of incomplete excision of LGFMS due to inappropriate diagnosis is stressed. It is this element that contributes most to the high rate of recurrence. We recommend that the eventuality of observing this rare tumor be borne in mind, and that care be taken to perform a complete, ample excision.

Orbital hyalinizing spindle cell tumor with giant rosettes

PURPOSE

To evaluate the clinical and histopathologic characteristics of orbital hyalinizing spindle cell tumor with giant rosettes (HSCTGR).

METHODS

Interventional case series of 2 patients, aged 4 and 9 years referred to the Ocular Oncology Unit. Both patients presented with slowly progressive proptosis with dimness of vision in the second patient. CT was performed for both patients followed by excision of the masses. Histology was performed on tissue sections.

RESULTS

CT revealed a localized tumor in the first case and extensive mass extending to the optic canal in the second patient. Histologic analysis revealed features of HSCTGR with characteristic spindle-shaped cells with giant rosettes with hyalinized foci. Tumor cells were positive for vimentin in both cases and focal S100 positivity in first case. However, the second case showed a higher Ki-67 index compared to the first case, suggestive of moderately high proliferative activity. After excision, neither of the tumors demonstrated local recurrence, and both patients were without regional or distant metastases. Mean clinical follow-up was 12 months.

CONCLUSIONS

HSCTGR involving the orbit has not been previously reported in the literature. We report 2 cases of orbital presentation at a much younger age than has been shown in patients with this type of tumor in other areas of the body. Complete excision of this tumor with close follow-up is the preferred treatment. HSCTGR should be considered in the differential diagnosis of orbital fibrous tumor presenting as painless progressive proptosis.

GNAS1 mutations occur more commonly than previously thought in intramuscular myxoma

Mutation detection plays an important role in diagnostic pathology, not only in providing a tissue diagnosis, but also in predicting response to antitumourigenic agents. However, mutation detection strategies are often hampered by masking of mutant alleles by wild-type sequences. Coamplification at lower denaturation temperature PCR (COLD-PCR) reportedly increases the proportion of rare variant sequences in a wild-type background by using PCR cycles in which the denaturation temperature is reduced to favour product formation with lower melt temperatures and heteroduplexes arising from minor variants. Intramuscular myxoma is a rare benign soft tissue neoplasm that occurs sporadically and less commonly in association with fibrous dysplasia (Mazabraud's syndrome). Fibrous dysplasia results from activating GNAS1 mutations, and the same mutations have been identified in small numbers of intramuscular myxoma. The aim of the study was primarily to establish whether COLD-PCR is more sensitive than conventional PCR; this was achieved by testing for GNAS1 mutations in intramuscular myxomas using the two methodologies. Mutations were detected in 8 of 28 (29%) cases of intramuscular myxomas using conventional PCR followed by mutation-specific restriction enzyme digestion (PCR-MSRED) whereas 17 of 28 (61%) mutations were detected using COLD-PCR/MSRED. Mutations were detected in two cases where a diagnosis of low-grade myxofibrosarcoma had been favoured over intramuscular myxoma. No mutations were detected in an additional 9 low-grade and 19 high-grade myxofibrosarcomas, and another 40 control samples. This study shows the power of COLD-PCR compared with conventional PCR in mutation detection, and shows that GNAS1 mutation detection increases diagnostic accuracy when distinguishing between intramuscular myxoma and low-grade myxofibrosarcoma.

Translocation-positive Low-grade Fibromyxoid Sarcoma: Clinicopathologic and Molecular Analysis of a Series Expanding the Morphologic Spectrum and Suggesting Potential Relationship to Sclerosing Epithelioid Fibrosarcoma

Low-grade fibromyxoid sarcomas (LGFMS) bear either the t(7,16) (q32-34;p11) or t(11,16) (p11;p11) translocations, resulting in FUS-CREB3L2 or FUS-CREB3L1 fusions, respectively. Heretofore, fusion transcripts were mainly detected in frozen tissues, using reverse transcription-polymerase chain reaction. In this study, we aimed to develop a reliable method to detect these in paraffin-embedded tissues, and to examine the clinicopathologic characteristics of a series of translocation-positive LGFMS. Sixty-three neoplasms with typical morphologic features of LGFMS and 66 non-LGFMS tumors selected for their resemblance to LGFMS (LGFMS-like tumors) were examined. RNA of sufficient quality could be extracted from 111/129 (86%) cases (59 LGFMS, 52 non-LGFMS). Of all, 48/59 (sensitivity, 81%) LGFMS contained detectable transcripts (45 FUS-CREB3L2, 3 FUS-CREB3L1). Most relevant clinicopathologic features of fusion-positive LGFMS included predominance in lower extremities (22/48; thigh: 13/48), deep situation (46/48), and occasional presence of unusual histologic features, for example, hypercellular areas (16/48), foci of epithelioid cells (13/48), and giant rosettes (6/48). Most tumors expressed EMA (41/45), at least focally, CD99 (38/41) and bcl-2 (36/41) while being essentially negative for CD34 (2/45), mdm2 (1/41), smooth muscle actin (1/45), S100 protein (0/46), desmin (0/44), h-caldesmon (0/42), keratins (0/44), and CD117 (0/40). Eleven presumed LGFMS were fusion negative. Of all, 7/52 non-LGMFS neoplasms contained FUS-CREB3L2 transcripts, of which 4 had been diagnosed as sclerosing epithelioid fibrosarcoma. In conclusion, FUS-CREB3L1/L2 fusion transcripts can be detected in paraffin-embedded LGFMS in a sensitive manner, using reverse transcription-polymerase chain reaction. Most fusion-positive LGFMS are EMA-positive and CD34/S100/smooth muscle actin negative. The presence of epithelioid cells and fusion transcripts in both LGFMS and a subset of sclerosing epithelioid fibrosarcoma suggest that these neoplasms might be related.

Low-grade fibromyxoid sarcoma: a brief review

Low-grade fibromyxoid sarcomas are uncommon deep soft tissue neoplasms first described by Evans in 1987. They exhibit a deceptively benign appearance, with a whorled or linear arrangement of spindle-shaped cells showing few to absent mitoses. A characteristic, but not specific, feature is the presence of areas of myxoid stroma. Recurrences are common, and late metastases have been recorded. A closely related but morphologically distinct tumor, the so-called hyalinizing spindle cell tumor with giant rosettes, has also been described; both neoplasms share the same cytogenetic abnormality, a balanced translocation resulting in a FUS/CREB3L2 fusion gene. Because of similar clinical behavior and the common cytogenetic abnormality, some authors prefer to consider both lesions as a single entity within the spectrum of low-grade sarcomas.

Characterization of large chromosome markers in a malignant fibrous histiocytoma by spectral karyotyping, comparative genomic hybridization (CGH), and array CGH

In this study, we characterized the chromosomal composition of an intra-abdominal soft tissue sarcoma diagnosed as a malignant fibrous histiocytoma (MFH). By applying a combination of spectral karyotyping, G-banding, and comparative genomic hybridization (CGH), this case was shown to carry large chromosome markers with material mainly from chromosomes 6 and 8. Further characterization of this unique tumor revealed high-level amplifications at the 6q21 approximately q23, 8p21 approximately pter, 8q24 approximately qter, and 12q13 approximately q21 regions. Using array CGH, these amplified regions were found to include MASL1 in 8p, as well s MDM2 and CDK4 in 12q, which have been shown to be amplified in MFH. Similarly, gains of 6q and 8q have also been seen in MFH. In conclusion, our study demonstrates the occurrence of large chromosome markers in MFH and suggests that the regions 6q21 approximately q23, 8p21 approximately pter, 8q24 approximately qter, and 12q13 approximately q21 might harbor oncogenes that could play a role in MFH's tumorigenesis. In addition, gain of 12q13 approximately q21, which is typical of well-differentiated liposarcoma, may also occur in MFH, supporting the previously suggested overlap in genetic etiologies between these two tumor types.

The chimericFUS/CREB3l2gene is specific for low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma (LGFMS) is a variant of fibrosarcoma that was recognized as a distinct tumor entity only quite recently. We previously described a translocation, t(7;16)(q33;p11), that resulted in a fusion of the FUS and CREB3L2 (also known as BBF2H7) genes in two soft tissue tumors that fulfilled morphologic criteria for LGFMS. To delineate the spectrum of tumors that may harbor the FUS/CREB3L2 gene, we selected 45 low-grade spindle cell sarcomas for reverse transcriptase polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH) analyses; none of these tumors had originally been diagnosed as LGFMS. Furthermore, also included were two benign soft tissue tumors and nine high-grade sarcomas with supernumerary ring chromosomes or 7q3 rearrangement and three tumors diagnosed as LGFMS prior to the genetic analysis. Of the 59 tumors analyzed, 12 were FUS/CREB3L2-positive, all of which were diagnosed at histopathologic re-examination as being LGFMS, of both the classical subtype and the subtype with giant collagen rosettes. The breakpoints in the fusion transcripts were always in exons 6 or 7 of FUS and exon 5 of CREB3L2. The results indicated that FUS/CREB3L2 is specifically associated with LGFMS and that RT-PCR or FISH analysis may be useful for the differential diagnosis.

Hyalinizing Spindle Cell Tumor with Giant Rosettes: A Case Report

Hyalinizing spindle cell tumor with giant rosettes (HSCTGR) is characterized by both giant rosette-like structures with collagen cores sparsely distributed throughout the tumor and fibromyxoid stroma. It is a rare low-grade sarcoma with indolent behavior, and wide excision with long-term follow-up is the best treatment. Although originally considered a distinct entity, it is now regarded as a variant of low-grade fibromyxoid sarcoma. We present a case of HSCTGR arising in the deep soft tissue of the left knee in a 50-year-old woman and provide a brief review of the literature for comparison.

Low grade fibromyxoid sarcoma of the falciform ligament: a case report

Background

Low grade fibromyxoid sarcomas (LGFMS) are very rarely seen. They commonly arise from deep soft tissues of the lower extremities. Very few cases of intra-abdominal location have been reported.

Case presentation

We report a 37 year old man who presented with an abdominal mass and dragging pain. Pre-operative imaging suggested the possibility of a subcapsular hemangioma of liver.

Conclusions

Laparoscopy was useful to locate the tumor as arising from falciform ligament and made the subsequent surgery simpler. This is one of the large fibromyxoid sarcomas to be reported.

Low-grade fibromyxoid sarcoma and hyalinizing spindle cell tumor with giant rosettes share a common t(7;16)(q34;p11) translocation

Low-grade fibromyxoid sarcoma (LGFMS) is a rare metastasizing soft tissue tumor with deceptively bland histologic features. The hyalinizing spindle cell tumor with giant rosettes (HSCT) is thought to be a closely related tumor differing only by the presence of collagen rosettes. We report the occurrence of a common t(7;16)(q34;p11) translocation in 2 cases of HSCT and 2 cases of LGFMS, thereby providing the first cytogenetic proof that LGFMS and HSCT are variants of the same entity. The tumors occurred in the thighs of 2 females and in the buttock and supraclavicular fossa of 2 males. One HSCT had a spectrum of unusual histologic features, including the presence of plump epithelioid cells with abundant cytoplasm and strands and nests of clear epithelioid cells separated by eosinophilic hyalinized stroma. Two cases showed a hitherto unreported, focal staining with epithelial membrane antigen, thus adding to the immunohistochemical profile of these tumors. LGFMS and HSCT probably have a wider spectrum of morphologic features than previously thought, the awareness of which will help pathologists to avoid diagnostic pitfalls. Demonstration of the t(7;16)(q34;p11) translocation will help to diagnose difficult cases with unusual histologic features.