Myxoinflammatory fibroblastic sarcoma with complex supernumerary ring chromosomes composed of chromosome 3 segments

Recent Advances in the Diagnosis, Pathogenesis, and Management of Myxoinflammatory Fibroblastic Sarcoma

Myxoinflammatory fibroblastic sarcoma (MIFS) is an infiltrative, locally aggressive fibroblastic neoplasm of intermediate malignancy that typically arises in the distal extremities of middle-aged adults. It can histologically be confused with a number of benign and malignant conditions. Recently, high-grade examples of MIFS have been described. Immunohistochemistry plays a very limited role in the diagnosis of MIFS. Several genetic alterations have been identified in MIFS, including a t(1;10)(p22;q24) translocation with TGFBR3 and/or OGA rearrangements, BRAF rearrangement, and VGLL3 amplification. Although it appears that VGLL3 amplification is the most consistent alteration, the molecular pathogenesis of MIFS remains poorly understood. A wide resection is considered the standard treatment for MIFS. Radiotherapy may be a viable option in cases with inadequate surgical margins or cases where surgery is likely to cause significant functional impairment. The systemic treatment options for advanced or metastatic disease are very limited. This review provides an updated overview of the clinicoradiological features, pathogenesis, histopathology, and treatment of MIFS.

Aggressive myxoinflammatory fibroblastic sarcoma with multiple site metastases

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare soft tissue sarcoma which was initially observed in acral sites and characterised by spindle cells, pleomorphic bizarre cells and distinctive large Reed-Sternberg-like cells admixed with an intense inflammatory cell infiltrates. MIFS manifests as a slow growing often superficial lesion which can be mistaken as infectious or chronic inflammatory process or benign tumours such as nodular fasciitis, giant cell tumour of tendon sheath or synovial pseudocyst. We report a rare presentation of a MIFS in a 38-year-old man with extensive local spread from subcutaneous tissue to the ankle joint and bones as well as multiple synchronous metastases to lung, sixth rib and vertebra. Our case is peculiar for its aggressive clinical behaviour with short duration, fast growth and extensive metastases, a feature infrequent in MIFS.

Recurrent BRAF Gene Rearrangements in Myxoinflammatory Fibroblastic Sarcomas, but Not Hemosiderotic Fibrolipomatous Tumors

Myxoinflammatory fibroblastic sarcoma (MIFS) is a low grade soft tissue sarcoma with a predilection for acral sites, being associated with a high rate of local recurrence but very infrequent distant metastases. Although a t(1;10) translocation resulting in TGFBR3-MGEA5 fusion has been reported as a recurrent genetic event in MIFS, this abnormality is seen only in a subset of cases. As no studies to date have investigated the spectrum of alternative genetic alterations in TGFBR3-MGEA5 fusion negative MIFS, we undertook a genetic analysis of this particular cohort for further molecular classification. Triggered by an index case occurring in the finger of a 37-year-old female and harboring a novel TOM1L2-BRAF fusion by targeted RNA sequencing we investigated potential recurrent BRAF abnormalities by screening a large group of 19 TGFBR3-MGEA5 fusion negative MIFS by fluorescence in situ hybridization. There were 6 (32%) additional MIFS with BRAF genetic abnormalities, including 5 gene rearrangements and one showing BRAF amplification. Interestingly, VGLL3 amplification, a recurrent genetic abnormality coexisting with t(1;10) in some MIFS, was also detected by fluorescence in situ hybridization in 4/6 (67%) BRAF-rearranged MIFS, but not in the BRAF-amplified case. Up-regulated VGLL3 mRNA expression was also demonstrated in the index case by RNA sequencing. The 7 BRAF-rearranged/amplified MIFS arose in the fingers (n=3), and 1 each in wrist, forearm, foot, and knee, of adult patients (36 to 74 y; M:F=4:3). The histologic spectrum ranged from predominantly solid growth of plump histiocytoid to epithelioid tumor cells with focal myxoid change to a predominantly myxoid background with scattered tumor cells. Varying degree of inflammatory infiltrates and large tumor cells with virocyte-like macronucleoli were observed in most cases. Immunohistochemical stains of phosphorylated ERK, a downstream effector of BRAF activation, were positive in all 4 cases tested (2 diffuse strong, 2 focal strong). Unlike t(1;10), BRAF rearrangements were only found in MIFS but not in 6 hemosiderotic fibrolipomatous tumor (HFLT) lacking TGFBR3-MGEA5 fusions (including 2 pure HFLT, 2 hybrid HFLT-MIFS, and 2 associated with pleomorphic hyalinizing angiectatic tumors).

Hemosiderotic Fibrolipomatous Tumor, Pleomorphic Hyalinizing Angiectatic Tumor, and Myxoinflammatory Fibroblastic Sarcoma: Related or Not?

Hemosiderotic fibrolipomatous tumor is an unusual, distinctive soft tissue neoplasm with locally recurring potential, which most commonly occurs in the ankle and foot. Morphologic evidence strongly suggests that hemosiderotic fibrolipomatous tumor is related to another rare, locally aggressive tumor of the distal extremities, pleomorphic hyalinizing angiectatic tumor, with areas identical to hemosiderotic fibrolipomatous tumor seen at the periphery in most if not all pleomorphic hyalinizing angiectatic tumor. This morphologic evidence is further supported by molecular genetic data, showing recurrent TGFBR3 and/or MGEA5 rearrangements in both hemosiderotic fibrolipomatous tumor and pleomorphic hyalinizing angiectatic tumor. A possible link between hemosiderotic fibrolipomatous tumor and yet another low-grade sarcoma of the distal extremities, myxoinflammatory fibroblastic sarcoma, has also been suggested based on the occurrence of unusual examples of hemosiderotic fibrolipomatous tumor showing progression to myxoid sarcoma, demonstrating some but not all features of myxoinflammatory fibroblastic sarcoma. These "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" also commonly show TGFBR3 and/or MGEA5 rearrangements. However, classic myxoinflammatory fibroblastic sarcoma lacks areas resembling hemosiderotic fibrolipomatous tumor, and shows a very low frequency of TGFBR3 and/or MGEA5 rearrangements in prospectively diagnosed cases. This suggests that so-called "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" represents a form of malignant progression within hemosiderotic fibrolipomatous tumor, rather than a lesion strictly related to classic myxoinflammatory fibroblastic sarcoma. This article will review the morphologic features, genetic features, and differential diagnosis of these rare neoplasms, and discuss their interrelation, or lack thereof.

Myxoinflammatory Fibroblastic Sarcoma: A Radiographical, Pathological, and Immunohistochemical Report of Rare Malignancy

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, painless, and intermediate (rarely metastasizing) fibroblastic tumor, which commonly occurs in the extremities, with an equal sex predilection. This sarcoma is composed of a mixed inflammatory infiltrate along with spindled, epithelioid, and bizarre tumor cells in a background of hyaline and myxoid areas. In spite of such a distinctive morphology, the tumor can be a diagnostic challenge, simulating inflammatory conditions as well as neoplastic nature. For accurate diagnosis, the tumor requires extensive clinical, radiological, and pathological investigations. We present a case of MIFS in a 19-year-old female who presented with a mass in the left ankle. After appropriate excision and postoperative radiation therapy, she is free of disease, including recurrence and metastasis, at 12 years postoperatively.

Myxoinflammatory fibroblastic sarcoma: morphologic and genetic updates

Myxoinflammatory fibroblastic sarcoma (MIFS) is a malignant mesenchymal neoplasm most frequently arising in the distal extremities of adults, which usually behaves in a low-grade manner but is capable of metastasizing to local and distant sites, rarely leading to death. It is a rare tumor whose unusual morphology can lead to erroneous histologic diagnosis, either as a nonneoplastic (infectious or inflammatory) process or as a variety of neoplastic diseases. While its exact origin is uncertain, ultrastructural studies have shown at least some of the constituent cells to be modified fibroblasts. Distinct and reproducible genetic abnormalities identified in MIFS are translocation t(1;10)(p22:q24), with rearrangements of the TGFBR3 and MGEA5 genes associated with increased levels of FGF8, and formation of marker/ring chromosome 3, with amplification of the VGLL3 locus. Because these genetic abnormalities are shared by both MIFS and hemosiderotic fibrohistiocytic lipomatous tumor, it is thought that these 2 morphologically distinct neoplasms may comprise a spectrum of disease defined by these genetics. We review the literature on MIFS and discuss morphology (including that of MIFS/hemosiderotic fibrohistiocytic lipomatous tumor hybrid lesions), immunohistochemistry, the differential diagnosis, and recent molecular genetic developments.

Myxoinflammatory fibroblastic sarcoma: a clinicopathologic analysis of 104 cases, with emphasis on predictors of outcome

In this study, we examine the clinicopathologic features of 104 cases of myxoinflammatory fibroblastic sarcoma (MIFS), a low-grade, inflammatory fibromyxoid tumor with a predilection to distal extremity soft tissue, and attempt to identify factors predictive of aggressive behavior. The study cohort consisted of 49 male and 55 female patients ranging in age from 17 to 83 (mean, 42; median, 39) years. The tumor arose primarily on the dorsal aspect of the distal extremities as a solitary and usually painless mass. Tumors ranged in size from 0.5 to 15 (mean, 3.2; median; 2.4) cm. Microscopically, tumors consisted of variably cellular and inflamed fibromyxoid tissue growing as a lobulated mass or as multiple nodules within subcutaneous tissue or along tendinofascial planes. Tumor cells ranged from plump spindled to more epithelioid cells with enlarged, vesicular nuclei. Characteristic of the process was a strikingly bizarre cell with an inclusion body-like nucleolus (85% of cases) and/or a smudgy hyperchromatic nucleus (51%) present in all but 7 cases. The mitotic rate per 50 high-power field ranged from 0 to 13 (mean, 2,9; median, 2) mitoses. Twenty-two tumors demonstrated 1 or more of the following atypical features: (1) foci with complex sarcoma-like vasculature; (2) hypercellular areas; and (3) increased mitotic activity or atypical mitotic figures. Immunohistochemically, tumor cells demonstrated immunoreactivity for vimentin (100%), D2-40 (86%), CD34 (50%), keratin(s) (33%), CD68 (27%), actin(s) (26%), desmin (9%), S-100 protein (7%), and epithelial membrane antigen (6%). Thirty of 59 patients (51%) with follow-up data suffered (at least) 1 local recurrence, and 1 patient developed metastatic disease after multiple local recurrences. Completeness of initial surgical excision was the only clinicopathologic parameter that statistically correlated with a lower incidence of recurrence (P=0.004). Histologically atypical MIFS recurred more often than conventional tumors (67% vs. 47%), but the difference was not statistically significant (P=0.35). Our study shows that histologic features often associated with more aggressive sarcomas do not substantially impact the morbidity of MIFS, and complete surgical excision provides the best chance for disease-free survival.

Myxoinflammatory fibroblastic sarcoma in children and adolescents: clinicopathologic aspects of a rare neoplasm

Myxoinflammatory fibroblastic sarcoma (MIFS), originally described as a low-grade malignant soft-tissue tumor in adults, has recently been reported in children and in non-acral sites. This report describes the clinicopathologic features of a series of 5 MIFS in children and adolescents (3 males, 2 females), ranging in age from 5 to 17 years (mean, 13 years). These tumors presented as small, superficial, slowly growing soft-tissues masses of the scalp, neck, middle finger, forearm, and thigh. Histologically, the tumors were composed of spindled and plump polygonal cells with prominent nuclear pleomorphism, nuclear pseudoinclusions; large eosinophilic nucleoli; myxoid foci intermingled with spindled foci; and an accompanying inflammatory infiltrate of lymphocytes, plasma cells, and variable neutrophils. Immunohistochemical analysis revealed variable reactivity for CD34 and smooth muscle actin in the tumor cells. Genetic analysis in 3 cases showed no rearrangements of TGFBR3 or MGEA5. Follow up in 4 cases revealed no recurrence or metastasis. These 5 cases of childhood and adolescent MIFS demonstrate an expanded age range and topographic distribution and a favorable outcome. The differential diagnosis and importance of recognizing this rare neoplasm in young patients are discussed.

A case of lung metastasis in myxoinflammatory fibroblastic sarcoma: analytical review of one hundred and thirty eight cases

PURPOSE

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare soft tissue tumour first identified at the end of the 1990s. This study presents our experience and literature reviews focusing on risk of recurrence.

METHODS

Rizzoli Orthopaedic Institute database and literature were searched for patients with MIFS observed from 1997 to 2012. Data were analysed in a new database.

RESULTS

Five patients underwent surgery at our institute, and 133 cases were retrieved from the literature. Not all clinicopathological data were available: 76/138 were men (55%), median age was 45 [interquartile range (IQR) 34-56] years, median tumour size was three (IQR two to five) centimetres. Common sites of occurrence were hand (24%), fingers (23%) and foot (20%). Pain was present at diagnosis in 14/82 patients (17%), with a median duration of seven (IQR three to 12) months. Surgery was performed for a suspected benign tumour in 88 patients (74%). Resection was incomplete in 45/71 cases (63%); re-excision was performed in 32/45 (71%). At a median follow-up of 26 months, 26/118 patients (22%) developed recurrent disease; median time to recurrence was 15 months (IQR seven to 26). Actuarial relapse-free survival (RFS) at one, three and five years was 93%, 72% and 67%, respectively. At univariate analysis, only symptom duration of six months or less was significantly associated with a worse RFS (p = 0.046). Metastatic disease to lymph nodes and/or lungs was observed in four patients (3%).

CONCLUSIONS

Clinicopathological findings confirm the low-grade nature of MIFS. However, local recurrence occurs, and patients may be affected by aggressive forms with a potential for distant metastases. Follow-up is strongly advised.

Updates on the cytogenetics and molecular cytogenetics of benign and intermediate soft tissue tumors

SOFT TISSUE TUMORS ARE CLASSIFIED ACCORDING TO THEIR HISTOLOGICAL RESEMBLANCE TO NORMAL ADULT TISSUES AND CAN BE GROUPED INTO THE FOLLOWING CATEGORIES BASED ON METASTATIC POTENTIAL: benign, intermediate (locally aggressive), intermediate (rarely metastasizing) and malignant. Over the past two decades, considerable progress has been made in our understanding of the genetic background of soft tissue tumors. Traditional laboratory techniques, such as cytogenetic analysis and fluorescence in situ hybridization (FISH), can be used for diagnostic purposes in soft tissue pathology practice. Moreover, cytogenetic and molecular studies are often necessary for prognostics and follow-up of soft tissue sarcoma patients. This review provides updated information on the applicability of laboratory genetic testing in the diagnosis of benign and intermediate soft tissue tumors. These tumors include nodular fasciitis, chondroid lipoma, collagenous fibroma (desmoplastic fibroblastoma), giant cell tumor of tendon sheath (GCTTS)/pigmented villonodular synovitis (PVNS), angiofibroma of soft tissue, myxoinflammatory fibroblastic sarcoma (MIFS) and ossifying fibromyxoid tumor (OFMT).

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.

Consistent t(1;10) with rearrangements of TGFBR3 and MGEA5 in both myxoinflammatory fibroblastic sarcoma and hemosiderotic fibrolipomatous tumor

Despite their shared predilection for superficial soft tissue of distal extremities and frequent local recurrences, myxoinflammatory fibroblastic sarcoma (MIFS) and hemosiderotic fibrolipomatous tumor (HFLT) have distinct morphologic appearances. Recent studies have identified an identical t(1;10)(p22;q24) in five cases of MIFS and two of HFLT, as well as common amplifications on 3p11-12. To investigate further their potential relationship and to determine the incidence of t(1;10) in a larger cohort, we subjected seven MIFS, 14 HFLT, and three cases with mixed morphology, to molecular and cytogenetic analysis. Fluorescence in situ hybridization (FISH) analysis for rearrangements of TGFBR3 on 1p22 and of MGEA5 on 10q24 was performed in all cases, whereas the status of VGLL3 gene amplification on 3p12.1 was investigated in 12 cases. Conventional karyotyping was performed in one HFLT and two cases with mixed MIFS/HFLT histology. Overall 83% of cases showed rearrangements in both TGFBR3 and MGEA5. All three cases with mixed features of MIFS and HFLT were positive. Cytogenetic analysis performed in three cases confirmed an unbalanced der(10)t(1;10)(p22;q24). VGLL3 gene amplification was noted in 10/12 cases of both histologies. The high incidence of t(1;10) in MIFS and HFLT reinforces a shared pathogenetic relationship. Furthermore, the co-existence of both components either synchronously or metachronously in a primary or subsequent recurrence, suggest either different morphologic variants or different levels of tumor progression of a single biologic entity. FISH analysis for TGFBR3 and MGEA5 rearrangements can be applied as a reliable diagnostic molecular test when confronted with limited material or a challenging diagnosis.

[Inflammatory myxohyaline tumor of the distal extremities]

Inflammatory myxohyaline tumor of the distal extremities is an extremely rare low-grade sarcoma with a tendency to produce local recurrence after surgical excision, but with a low metastatic potential. We present the case of a 49-year-old woman with a slow-growing asymptomatic tumor on the right pretibial region that was initially considered to be a lipoma. Histopathology revealed the presence of a polymorphic inflammatory infiltrate within a myxoid and hyaline matrix. Interspersed between the inflammatory cells were 3 different populations of neoplastic cells: atypical spindle-shaped cells; bizarre epithelioid cells, some of which were multinucleated and resembled the virocytes or Reed-Sternberg cells; and cells with abundant, vacuolated cytoplasm, similar to lipoblasts. These clinical-pathologic findings led to a diagnosis of inflammatory myxohyaline tumor of the distal extremities. Although the tumor was excised with wide surgical margins, local recurrence developed after 3 months and was treated with re-excision and radiotherapy.

Hybrid myxoinflammatory fibroblastic sarcoma/hemosiderotic fibrolipomatous tumor: report of a case providing further evidence for a pathogenetic link

Myxoinflammatory fibroblastic sarcoma and hemosiderotic fibrolipomatous tumor are rare, slow-growing soft tissue tumors of the distal extremities with recurrent potential. Recent cytogenetic studies have shown a t(1;10)(p22;q24) or der(10)t(1;10) in combination with aberrations of chromosome 3 in a limited number of cases of both entities. Here we report a case of a 42-year-old female with a soft tissue tumor of the ankle showing hybrid morphologic features of myxoinflammatory fibroblastic sarcoma and hemosiderotic fibrolipomatous tumor, a der(10)t(1;10), and abnormalities of chromosome 3. This hybrid lesion provides further evidence for a close relationship between these 2 tumor types.

Soft tissue sarcomas with complex genomic profiles

Soft tissue sarcomas (STS) with complex genomic profiles (50% of all STS) are predominantly composed of spindle cell/pleomorphic sarcomas, including leiomyosarcoma, myxofibrosarcoma, pleomorphic liposarcoma, pleomorphic rhabdomyosarcoma, malignant peripheral nerve sheath tumor, angiosarcoma, extraskeletal osteosarcoma, and spindle cell/pleomorphic unclassified sarcoma (previously called spindle cell/pleomorphic malignant fibrous histiocytoma). These neoplasms show, characteristically, gains and losses of numerous chromosomes or chromosome regions, as well as amplifications. Many of them share recurrent aberrations (e.g., gain of 5p13-p15) that seem to play a significant role in tumor progression and/or metastatic dissemination. In this paper, we review the cytogenetic, molecular genetic, and clinicopathologic characteristics of the most common STS displaying complex genomic profiles. Features of diagnostic or prognostic relevance will be discussed when needed.

A rare case of acral myxoinflammatory fibroblastic sarcoma at the hand

One case of acral myxoinflammatory fibroblastic sarcoma is presented. Most of the soft tissue tumefactions of the distal extremities are benign. Sarcomas are rare and usually high grade. Acral myxoinflammatory fibroblastic sarcoma is a unique low-grade tumor described by Kindblom in 1998. This neoplasm has a propensity for digits, presents a low rate of metastasis and is characterized by a high rate of local multiple and aggressive recurrence. The clinical presentation, the frequent association with tenosynovitis and the extensive inflammatory infiltrate can lead to misdiagnosis by both the surgeon and the pathologist. Correct and early diagnosis depends on a good knowledge of histological and immunohistochemical findings. It is important to avoid recurrences recurring to an immediate wide excision of the tumor.

Myxoinflammatory fibroblastic sarcoma showing t(2;6)(q31;p21.3) as a sole cytogenetic abnormality

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade sarcoma characterized by distinctive, large, and bizarre Reed--Sternberg--like cells associated with an intense inflammatory infiltrate. The biology of MIFS is still poorly understood, and only two previous cases had been studied cytogenetically. In the present case, analysis of MIFS in the foot of a 53-year-old man revealed the chromosome translocation t(2;6)(q31;p21.3) as the only cytogenetic abnormality. This finding is distinct from the two cases previously reported. Additional studies are needed to verify whether any of these chromosome rearrangements are involved recurrently in MIFS.

Myxoinflammatory fibroblastic sarcoma: investigations by comparative genomic hybridization of two cases and review of the literature

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare low-grade sarcoma of the distal extremities characterized by a myxohyaline stroma, a dense inflammatory infiltrate and virocyte- and lipoblast-like giant cells. Up to now, only two cases have been investigated cytogenetically, showing complex and heterogeneous karyotypes, in part with supernumerary ring chromosomes. We characterized two further cases of MIFS immunohistochemically and performed comparative genomic hybridization as well as DNA image cytometry analyses. Both tumors showed the characteristic histomorphological pattern of MIFS and were positive for Vimentin and CD68. Moreover, both cases presented aberrant karyotypes including distinct DNA copy number changes involving chromosome 7 and disclosed DNA aneuploidy.

Myxoinflammatory fibroblastic sarcoma in an unreported area (groin)

BACKGROUND

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare tumor presenting as a painless subcutaneous mass in the extremities first reported in 1998. We report the first case of a MIFS tumor in the groin.

METHODS

We have performed seven immunohistochemical stains that were not applied before on MIFS.

RESULTS

The first case of a MIFS tumor in the groin.

CONCLUSIONS

MIFS must be considered in the differential diagnosis of a painless mass not only in the distal extremities but also in the groin. The diagnosis of this tumor is difficult and can be missed if not considered because of the unusual location. Due to high recurrence rates and one case of documented metastases, the recommended treatment is wide excision.

Genomic profiling of bone and soft tissue tumors with supernumerary ring chromosomes using tiling resolution bacterial artificial chromosome microarrays

Ring chromosomes and/or giant marker chromosomes have been observed in a variety of human tumor types, but they are particularly common in a subgroup of mesenchymal tumors of low-grade or borderline malignancy. These rings and markers have been shown to contain amplified material predominantly from 12q13-15, but also sequences from other chromosomes. Such amplified sequences were mapped in detail by genome-wide array comparative genomic hybridization in ring-containing tumor samples from soft tissue (n = 15) and bone (n = 6), using tiling resolution microarrays, encompassing 32 433 bacterial artificial chromosome clones. The DNA copy number profiles revealed multiple amplification targets, in many cases highly discontinuous, leading to delineation of large numbers of very small amplicons. A total number of 356 (median size: 0.64 Mb) amplicons were seen in the soft tissue tumors and 90 (median size: 1.19 Mb) in the bone tumors. Notably, more than 40% of all amplicons in both soft tissue and bone tumors were mapped to chromosome 12, and at least one of the previously reported recurrent amplifications in 12q13.3-14.1 and 12q15.1, including SAS and CDK4, and MDM2, respectively, were present in 85% of the soft tissue tumors and in all of the bone tumors. Although chromosome 12 was the only chromosome displaying recurrent amplification in the bone tumors, the soft tissue tumors frequently showed recurrent amplicons mapping to other chromosomes, that is, 1p32, 1q23-24, 3p11-12, 6q24-25 and 20q11-12. Of particular interest, amplicons containing genes involved in the c-jun NH2-terminal kinase/mitogen-activated protein kinase pathway, that is, JUN in 1p32 and MAP3K7IP2 (TAB2) in 6q24-25, were found to be independently amplified in eight of 11 cases with 12q amplification, providing strong support for the notion that aberrant expression of this pathway is an important step in the dedifferentiation of liposarcomas.

Myxoinflammatory fibroblastic sarcoma of the neck

BACKGROUND

Myxoinflammatory fibroblastic sarcoma (MIFS), also named inflammatory myxohyaline tumor of distal extremities with virocyte or Reed-Sternberg cells, is a rare tumor typically presenting as a painless mass in the extremities.

PATIENTS

We present an unusual case of MIFS presenting as a subcutaneous neck mass. This is the first reported case of MIFS presenting in the neck.

RESULTS

Therefore, this lesion must be considered in the differential diagnosis for painless subcutaneous masses presenting not only in the distal extremities, but also in the neck.

CONCLUSION

MIFS has only recently been recognized. The differential diagnosis for MIFS is broad, and it can often be mistaken for several different inflammatory and neoplastic processes, which may require different treatment.