Sclerosing epithelioid fibrosarcoma | |
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Specialty | Dermatology, Dermatopathology, Pathology, Surgical oncology, Oncology |
Causes | Unknown |
Treatment | Surgical removal of tumor |
Prognosis | Guarded |
Sclerosing epithelioid fibrosarcoma (SEF) is a very rare malignant tumor of soft tissues that on microscopic examination consists of small round or ovoid neoplastic epithelioid fibroblast-like cells, i.e. cells that have features resembling both epithelioid cells and fibroblasts. [1] In 2020, the World Health Organization classified SEF as a distinct tumor type in the category of malignant fibroblastic and myofibroblastic tumors. [2] However, current studies have reported that low-grade fibromyxoid sarcoma (LGFMS) has many clinically and pathologically important features characteristic of SEF; these studies suggest that LGSFMS may be an early form of, and over time progress to become, a SEF. [3] [4] [5] [6] Since the World Health Organization has classified LGFMS as one of the malignant fibroblastic and myofibroblastic tumors that is distinctly different than SEF, [2] SEF and LGFMS are here regarded as different tumor forms.
Sclerosing epithelioid fibrosarcomas are aggressive tumors that usually develop in adults and elderly individuals [7] or, in a small minority of cases, children. [1] SEF tumors often occur in a shoulder, hip, or lower areas of the legs and arms or, less commonly, in a vital organ or other tissue location that may be in virtually any part of the body. [7] SEF tumors tend to recur at the site where they are surgically removed, to metastasize to other tissues, and to have poor outcomes. [7]
Surgical resection of the primary or recurrent tumor with or without adjuvant radiation therapy has been the mainstay treatment for SEF. This treatment is often employed in order to achieve control of the tumor's local injurious effects. The sensitivity of SEF tumors to various chemotherapy regimens has been very limited. [6] The prognosis of SEF is guarded because surgery with or without radiation therapy and chemotherapy frequently does not stop, or only stops for a short time, the progression of this disease. [6] [8]
Individuals presenting with SEF tumors are 3 [1] to 87 years old [1] (median age 44.6 years [9] ) with most individuals aged 30-60 years. [7] These tumors involve the lower limb and shoulder areas (28.3% of cases), trunk (18.7%), head and neck areas (11.7%), lung and its pleura (10.0%), bone (including the spinal vertebrae [6] ) (10.0%), soft tissues (9.1%), upper limb and shoulder areas (7.5%), kidney (3.9%), pancreas (0.9%), liver (0.4%), and brain (0.4%). [1] Rare cases of SEF tumors have developed in the ovary and lower gastrointestinal tract. [10] In two separate studies, 17% [9] and 27% [11] of patients presented with metastases at the time of the initial diagnosis of their disease. While most individuals present with a painless mass, [5] about 33% report having a painful and enlarging mass. The tumor may have been noticed and even painful for a few months to years. [5] Tumors developing in the head, abdominal cavity, or other space-constrained sites often present with symptoms and signs related to their tumors' mass effects. [5] For example, 5 of 5 patients diagnosed with SEF tumors in the spinal vertebrae presented with pain that they had experienced for 3 to 6 months [6] and 2 of 2 patients with a SEF located in the buttock presented with highly painful sciatica. [10] SEF tumors have varied in size from 1 to 25 cm in diameter (average diameter, 8.3 cm). [11] In one small study, all individuals treated with surgical resection of their tumors, re-presented with recurrences of their tumors at the sites of their surgical removal and 91% re-presented with metastases (67% to the lung, 50% to bone, and 1 case each to the liver, brain and abdomen). [1]
As defined by microscopic histopathologic analyses of hematoxylin and eosin stained tissue samples, SEF tumors vary from lower to higher cellular lesions. These cells are small-to-moderate-sized epitheliod-like cells that on ultrastructural analyses have features of fibroblasts and myofibroblasts. The cells contain moderate numbers of mitochondria, abundant rough endoplasmic reticulum networks, large Golgi complexes, and cytoplasmic arrays of vimentin intermediate filaments. The cells tend to be grouped into nests, sheets, cords, and/or single files embedded in an eosinophilic (i.e. more blue or purple compared to normal connective tissue because of excessive uptake of the hematoxylin stain), sclerotic (i.e. hardened) connective tissue background. The connective tissue background contains irregular, thin-walled, distended blood vessels and may have foci of hyaline cartilage, bone formation, and necrosis (clumps of dead or dying cells). [5]
Immunohistochemical analyses find that the neoplastic cells in SEF tumors typically express MUC1, [12] vimentin, Bcl-2, CD99, and MUC4 marker proteins. [13] MUC1, vimentin, CD99, and Bcl-2 marker proteins are expressed in the neoplastic cells of various types of other tumors and therefore do not distinguish between these tumors and SEF. However the expression of MUC4 is found mainly in the neoplastic cells of SEF and low-grade fibroblastic tumors. Consequently, the expression of the MUC4 marker protein in tumor cells suggests that these tumors are either a SEF or low-grade fibromyxoid sarcoma rather than certain mimickers of SEF. [14] SEF tumors with MUC4-negative neoplastic cells may be more aggressive than SEF tumors with MUC4-positive neoplastic cells. [9]
Several genetic alterations in SEF neoplastic cells are fusion genes. A fusion gene is a hybrid gene formed from two previously independent genes due to a chromosome translocation, deletion in some of the genetic material in a chromosome, or chromosomal inversion. [12] For example, the EWSR1-CREB3L1 fusion gene expressed by SEF neoplastic cells is made by a chromosomal translocation which unites part of the EWSR1 gene normally located on band 12.2 of the long (or "q") arm of chromosome 22 [15] with part of the CREB3L1 gene normally located on band 11.2 of the short arm of chromosome 11. [16] This particular fusion gene is predicted to be functional, i.e. capable of forming an EWSR1-CREB3L1 chimeric protein product. [13] The largest study to date tested 26 SEF patients for certain types of gene rearrangements in their tumors' neoplastic cells. The study found that these tumor cells expressed: the EWSR1-CREB3L1 fusion gene in 7 cases, the EWSR1-CREB3L2 fusion gene in 1 case, the FUS-CREB3L2 fusion gene in 3 cases, the YAP1-KMT2A fusion gene in 2 cases, other types of rearrangements (e.g. deletions) in one or both of their EWSR1 genes in 12 cases, and inconclusive results in 1 case. [8] A smaller study found the EWSR1-CREB3L1 fusion gene in the neoplastic cells of 3 of 8 and EWSR1 gene rearrangements in 2 of 8 SEF cases. [17] The neoplastic cells in rare cases of SEF have been reported to express a PAX5-CREB3L1 , EWSR1-CREB3L3 , EWSR1-CREM , YAP1-KMT2A , or KMT2D-PRRX1 fusion gene. [7]
The products made by the CREB3L1, CREB3L2, and CREB3L3 genes are cAMP response element-binding protein transcription factors which regulate cell proliferation, survival, and the development of gene maturations. [9] The EWSR1 and FUS gene product proteins belong to the FET protein family of proteins which regulate gene expression as well as mRNA/micro-RNA processing and may contribute to the development of various cancers. [18] The YAP1 gene product, yes-associated protein, contributes to the regulation of cell proliferation and apoptosis, i.e. programmed cell death (see YAP1 ). {The YAP1 gene is an oncogene, i.e. a potential cancer-causing gene). The KMT2A and KMT2D gene product proteins regulate gene transcription and may contribute to the development of various cancers (see KMT2A and KMT2D ). And, the PRRX1 gene product protein regulates epithelial-mesenchymal transition and may be involved in the development of various cancers. [19]
Further studies are needed to determine if any of these fusion genes produce chimeric proteins that retain the cancer-promoting activity of their protein components and thereby contribute to the development and/or progression of SEF. However, the presence of these fusion genes in a tumor can be helpful in determining if a tumor is an SEF or some other neoplasia that can mimic SEF (see Diagnosis section). [1] [13] [17]
Based on their presentation and pathology, SEF tumors can be very difficult to differentiate from some cases of desmoid tumors, nodular fasciitis, and low-grade fibromyxoid sarcomas. Relative to the latter three tumor types, however, the presence of tumor neoplastic cells that: 1) express the MUC4 marker protein and a FUS-CREB3L2 fusion gene or an otherwise rearranged FUS gene strongly suggest that the tumor is a SEF; [9] 2) express the EWSR1-CREB3L1 fusion gene suggest that the tumor is a SEF [8] but in any case is unlikely to be a low-grade fibromyxoid sarcoma. [9] 3) express a FUS-CREB3L2 fusion gene is more likely to be a low-grade fibromyxoid sarcoma than a SEF (i.e. the FUS-CREB3L2 fusion gene is present in >90% of low-grade fibromyxoid sarcomas but only ~20% of SEF tumor cells [17] ); or 4) express an EWSR1-CREB3L1 or EWSR1-CREB3L2 fusion gene is likely to be a SEF tumor. [14] SEF tumors have also been mistaken for rare types of other sarcomas that sometimes have epithelioid features such as mesenchymal chondrosarcomas, Ewing sarcomas, osteosarcomas, sclerosing variants of rhabdomyosarcoma, or leiomyosarcomas. They also may be mistaken for certain metastatic carcinomas such as signet ring cell carcinoma and lobular forms of breast cancer. Extensive immunohistochemistry analyses can help to differentiate these tumors from SEF tumors. [5] [8]
Surgical resection has been the mainstay treatment for sclerosing epithelioid fibrosarcoma tumors. However, these tumors are often located where complete surgical removal is not feasible, where the tumor is too large or tissue-infiltrating for complete surgical removal, [7] and/or where the tumor is associated with distant metastases. [11] Consequently, SEF tumors have commonly been treated with wide local excision, amputation of an involved extremity, radiotherapy, and/or chemotherapy, depending on the tumors surgical accessibility and spread to other tissues. [5] Often, however, the goal of these treatment regimens is to obtain control of the tumor's local harmful effects. [6] In one study, among 45 patients presenting with SEF tumors, 38 underwent surgical resection with 3 having a second resection because tumor tissue had been left behind; 2 underwent debulking without removal of all the tumor tissue; 2 had supportive care for unresectionable disease; 6 had resection of local recurrences; 6 underwent surgical resections of metastatic tumors; 25 underwent radiation therapy aimed at treating both the primary and associated metastatic tumors; and 26 received chemotherapy for primary, recurrent, and, in particular, metastatic disease. The chemotherapy regimens included one or more of the following drugs, doxorubicin, ifosfamide, docetaxel, gemcitabine, pazopanib, vincristine, cisplatin, cyclophosphamide, etoposide, and/or dacarbazine. [8] Nonetheless, studies suggest that radiotherapy should only be administered in cases where surgery is impossible and/or has the potential to slow the progression of the disease [7] and all currently used chemotherapeutic regimens have generally been ineffective in controlling these tumors. [5] [6] [8]
In a study of 45 patients with SEF, 19 were alive with disease after a median time of 41 months (range: 6 to 264 months), 19 died of the disease at a median of 49 months (range: 5 to 216 months), and 5 had no evidence of disease at a median of 63 months (range: 18 to 120 months) after being diagnosed with and then treated for their disease. [8] In another study of 13 patients who were followed long-term, 12 patients developed metastatic disease of which 10 died; the overall survival median time after diagnosis was 47.3 months and after metastasis was 16.3 months. However, there was a wide range in the survival of these patients: while 4 died within the first year of diagnosis, 7 reached the 3-year survival mark, some survived for >10 years, and several continued to be clinically well for a number of years after developing metastatic disease. [9]
A sarcoma is a malignant tumor, a type of cancer that arises from cells of mesenchymal origin. Connective tissue is a broad term that includes bone, cartilage, muscle, fat, vascular, or other structural tissues, and sarcomas can arise in any of these types of tissues. As a result, there are many subtypes of sarcoma, which are classified based on the specific tissue and type of cell from which the tumor originates.
Dermatofibrosarcoma protuberans (DFSP) is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis). Estimates of the overall occurrence of DFSP in the United States are 0.8 to 4.5 cases per million persons per year. In the United States, DFSP accounts for between 1 and 6 percent of all soft-tissue sarcomas and 18 percent of all cutaneous soft-tissue sarcomas. In the Surveillance, Epidemiology and End Results (SEER) tumor registry from 1992 through 2004, DFSP was second only to Kaposi sarcoma.
Liposarcomas are the most common subtype of soft tissue sarcomas, accounting for at least 20% of all sarcomas in adults. Soft tissue sarcomas are rare neoplasms with over 150 different histological subtypes or forms. Liposarcomas arise from the precursor lipoblasts of the adipocytes in adipose tissues. Adipose tissues are distributed throughout the body, including such sites as the deep and more superficial layers of subcutaneous tissues as well as in less surgically accessible sites like the retroperitoneum and visceral fat inside the abdominal cavity.
Undifferentiated pleomorphic sarcoma (UPS), also termed pleomorphic myofibrosarcoma, high-grade myofibroblastic sarcoma, and high-grade myofibrosarcoma, is characterized by the World Health Organization (WHO) as a rare, poorly differentiated neoplasm. WHO classified it as one of the undifferentiated/unclassified sarcomas in the category of tumors of uncertain differentiation. Sarcomas are cancers derived mesenchymal stem cells that typically develop in bone, muscle, fat, blood vessels, lymphatic vessels, tendons, and ligaments. More than 70 sarcoma subtypes have been described. The UPS subtype of these sarcomas consists of tumor cells that are poorly differentiated and may appear as spindle-shaped cells, histiocytes, and giant cells. UPS is considered a diagnosis that defies formal sub-classification after thorough histologic, immunohistochemical, and ultrastructural examinations fail to identify the type of cells involved.
Congenital mesoblastic nephroma, while rare, is the most common kidney neoplasm diagnosed in the first three months of life and accounts for 3-5% of all childhood renal neoplasms. It is generally non-aggressive and amenable to surgical removal, though there is a subtype that is more aggressive and tends to spread to other organs. Congenital mesoblastic nephroma was first named as such in 1967 but was recognized decades before this as fetal renal hamartoma or leiomyomatous renal hamartoma. It is embryologically derived from the metanephrogenic blastema, the same tissue that gives rise to nephroblastomatosis and Wilms tumor.
The Ewing family of tumors (EFTs) is a group of small cell sarcomas including Ewing sarcoma of the bone, extra osseous Ewing tumors, and primitive neuroectodermal tumors. They are rare cancers, usually diagnosed in peoples' twenties. The sarcoma of bone is the most common of the variants. All forms are predisposed to metastasis and have had historically high rates of mortality. The family of tumors shares a common translocation mutation of the EWS gene on chromosome 22 to an ETS-type gene, most commonly the FLI1 gene. EFTs are highly malignant, with 5-year survival for patients with metastatic disease at 20%. The current standard of care includes resection, radiation, and chemotherapy.
Clear cell sarcoma is a sub-type of a rare form of cancer called a sarcoma. It is known to occur mainly in the soft tissues and dermis. Rare forms were thought to occur in the gastrointestinal tract before they were discovered to be different and redesignated as gastrointestinal neuroectodermal tumors.
Extraskeletal myxoid chondrosarcoma (EMC) is a rare low-grade malignant mesenchymal neoplasm of the soft tissues, that differs from other sarcomas by unique histology and characteristic chromosomal translocations. There is an uncertain differentiation and neuroendocrine differentiation is even possible.
Porocarcinoma (PCA) is a rare form of skin cancer that develops in eccrine sweat glands, i.e. the body's widely distributed major type of sweat glands, as opposed to the apocrine sweat glands which are located primarily in the armpits and perineal area. This cancer typically develops in individuals as a single cutaneous tumor in the intraepidermal spiral part of these sweat glands' ducts at or near to where they open on the skin's surface. PCA tumors are classified as one form of the cutaneous adnexal tumors; in a study of 2,205 cases, PCA was the most common (11.8%) form of these tumors.
Low-grade fibromyxoid sarcoma (LGFMS) is a rare type of low-grade sarcoma first described by H. L. Evans in 1987. LGFMS are soft tissue tumors of the mesenchyme-derived connective tissues; on microscopic examination, they are found to be composed of spindle-shaped cells that resemble fibroblasts. These fibroblastic, spindle-shaped cells are neoplastic cells that in most cases of LGFMS express fusion genes, i.e. genes composed of parts of two different genes that form as a result of mutations. The World Health Organization (2020) classified LGFMS as a specific type of tumor in the category of malignant fibroblastic and myofibroblastic tumors.
Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm of the mesodermal cells that form the connective tissues which support virtually all of the organs and tissues of the body. IMT was formerly termed inflammatory pseudotumor. Currently, however, inflammatory pseudotumor designates a large and heterogeneous group of soft tissue tumors that includes inflammatory myofibroblastic tumor, plasma cell granuloma, xanthomatous pseudotumor, solitary mast cell granuloma, inflammatory fibrosarcoma, pseudosarcomatous myofibroblastic proliferation, myofibroblastoma, inflammatory myofibrohistiocytic proliferation, and other tumors that develop from connective tissue cells. Inflammatory pseudotumour is a generic term applied to various neoplastic and non-neoplastic tissue lesions which share a common microscopic appearance consisting of spindle cells and a prominent presence of the white blood cells that populate chronic or, less commonly, acute inflamed tissues.
CAMP responsive element binding protein 3 like 1, also known as OASIS, is a responsive element binding protein that in humans is encoded by the CREB3L1 gene.
Tazemetostat, sold under the brand name Tazverik, is a medication used for the treatment of adults and adolescents aged 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete resection.
Acral myxoinflammatory fibroblastic sarcoma (AMSF), also termed myxoinflammatory fibroblastic sarcoma (MSF), is a rare, low-grade, soft tissue tumor that the World Health Organization (2020) classified as in the category of rarely metastasizing fibroblastic and myofibroblastic tumors. It is a locally aggressive neoplasm that often recurs at the site of its surgical removal. However, it usually grows slowly and in only 1–2% of cases spreads to distant tissues.
Fibroblastic and myofibroblastic tumors (FMTs) are tumors which develop from the mesenchymal stem cells which differentiate into fibroblasts and/or the myocytes/myoblasts that differentiate into muscle cells. FMTs are a heterogeneous group of soft tissue neoplasms. The World Health Organization (2020) defined tumors as being FMTs based on their morphology and, more importantly, newly discovered abnormalities in the expression levels of key gene products made by these tumors' neoplastic cells. Histopathologically, FMTs consist of neoplastic connective tissue cells which have differented into cells that have microscopic appearances resembling fibroblasts and/or myofibroblasts. The fibroblastic cells are characterized as spindle-shaped cells with inconspicuous nucleoli that express vimentin, an intracellular protein typically found in mesenchymal cells, and CD34, a cell surface membrane glycoprotein. Myofibroblastic cells are plumper with more abundant cytoplasm and more prominent nucleoli; they express smooth muscle marker proteins such as smooth muscle actins, desmin, and caldesmon. The World Health Organization further classified FMTs into four tumor forms based on their varying levels of aggressiveness: benign, intermediate, intermediate, and malignant.
Myxofibrosarcoma (MFS), although a rare type of tumor, is one of the most common soft tissue sarcomas, i.e. cancerous tumors, that develop in the soft tissues of elderly individuals. Initially considered to be a type of histiocytoma termed fibrous histiocytoma or myxoid variant of malignant fibrous histiocytoma, Angervall et al. termed this tumor myxofibrosarcoma in 1977. In 2020, the World Health Organization reclassified MFS as a separate and distinct tumor in the category of malignant fibroblastic and myofibroblastic tumors.
The FET protein family consists of three similarly structured and functioning proteins. They and the genes in the FET gene family which encode them are: 1) the EWSR1 protein encoded by the EWSR1 gene located at band 12.2 of the long arm of chromosome 22; 2) the FUS protein encoded by the FUS gene located at band 16 on the short arm of chromosome 16; and 3) the TAF15 protein encoded by the TAF15 gene located at band 12 on the long arm of chromosome 7 The FET in this protein family's name derives from the first letters of FUS, EWSR1, and TAF15.
Angiofibroma of soft tissue (AFST), also termed angiofibroma, not otherwise specified, is a recently recognized and rare disorder that was classified in the category of benign fibroblastic and myofibroblastic tumors by the World Health Organization in 2020. An AFST tumor is a neoplasm that was first described by A. Mariño-Enríquez and C.D. Fletcher in 2012.
Dermatofibrosarcoma protuberans, fibrosarcomatous (DFSP-FS), also termed fibrosarcomatous dermatofibrosarcoma protuberans, is a rare type of tumor located in the dermis. DFSP-FS tumors have been viewed as: 1) a more aggressive form of the dermatofibrosarcoma protuberans (DFSP) tumors because they have areas that resemble and tend to behave like malignant fibrosarcomas or 2) as a distinctly different tumor than DFSP. DFSP-FS tumors are related to DFSP. For example, surgically removed DFSP tumors often recur with newly developed fibrobosarcoma-like areas. Nonetheless, the World Health Organization (WHO), 2020, classified DFSP and DFSP-FS as different tumors with DFSP being in the category of benign and DFSP-FS in the category of rarely metastasizing fibroblastic and myofibroblastic tumors. This article follows the WHO classification: the 5-15% of DFSP tumors that have any areas of fibrosarcomatous microscopic histopathology are here considered DFSP-FS rather than DFSP tumors.
Low-grade myofibroblastic sarcoma (LGMS) is a subtype of the malignant sarcomas. As it is currently recognized, LGMS was first described as a rare, atypical myofibroblastic tumor by Mentzel et al. in 1998. Myofibroblastic sarcomas had been divided into low-grade myofibroblastic sarcomas, intermediate‐grade myofibroblasic sarcomas, i.e. IGMS, and high‐grade myofibroblasic sarcomas, i.e. HGMS based on their microscopic morphological, immunophenotypic, and malignancy features. LGMS and IGMS are now classified together by the World Health Organization (WHO), 2020, in the category of intermediate fibroblastic and myofibroblastic tumors. WHO, 2020, classifies HGMS as a soft tissue tumor in the category of tumors of uncertain differentiation. This article follows the WHO classification: here, LGMS includes IGMS but not HGMS which is a more aggressive and metastasizing tumor than LGMS and consists of cells of uncertain origin.