Involvement of 3q21 in nodular fasciitis

Ubiquitin-specific Peptidase 6 (USP6)-associated Fibroblastic/Myofibroblastic Tumors: Evolving Concepts

Ubiquitin-specific peptidase 6 (USP6) is a hominoid-specific gene residing on chromosome 17p13 and serves as a deubiquitinating enzyme with a diverse set of functions including intracellular trafficking, inflammatory signaling, cell transformation and protein turnover. USP6 rearrangements were first identified in aneurysmal bone cysts, resulting in promoter swapping and over-expression of wild type USP6. Several morphologically overlapping fibroblastic/myofibroblastic tumors are known to harbor USP6 rearrangements, including nodular fasciitis, cellular fibroma of tendon sheath, myositis ossificans and fibro-osseous pseudotumor of digits. Over the past few years, fusions involving the USP6 gene and various partner genes have been described in these neoplasms. The current World Health Organization Classification of Tumors of Soft Tissue suggests that USP6-rearranged lesions are typically benign and usually self-limited in their growth. This review provides an updated overview of the clinical, histological and molecular genetic features of USP6-associated fibroblastic/myofibroblastic tumors and discusses how these lesions should be best classified.

Polypoid Carcinoma of the Oropharynx with Stromal Ossifying Myofibroblastic Proliferation: A Case Report and Literature Review

A 76-year-old man reported a worsening difficulty in swallowing, leading to the inability to eat. Physical examination and CT scan revealed a polypoid mass on the posterior oropharynx and obstructing the oropharyngeal space. Histologically, the surface was ulcerated. In the underlying necrotic rim, there was active granulation tissue, and a proliferation of voluminous, globoid elements with hyperchromatic and irregular nucleus, sometimes arranged in a alveolar aggregate. The core of the lesion contained spindle-like myoid elements in interwoven bundles, with trabeculae of osteoid matrix maturing into calcified bone. Immunohistochemistry documented positivity for cytokeratins, epithelial membrane antigen, and P63 in the globoid elements beneath the necrotic rim; strong and diffuse expression of vimentin, smooth muscle actin, and CD99 and BCL2 in the spindle elements; and complete negativity for cytokeratin 5/6, high molecular weight cytokeratin (clone 34βE12), S100, muscle-specific actin, desmin, CD117, and anaplastic lymphoma kinase. The lesion was morphologically and immunophenotypically classified as a polypoid oropharyngeal carcinoma with ossifying myofibroblastic stromal proliferation.

Nodular fasciitis of the vulva: a challenging histopathologic diagnosis supported by the detection of USP6 gene rearrangement

Nodular fasciitis involving the vulva on physical examination can mimic a Bartholin gland lesion, and histologically can have overlapping features with more ominous mesenchymal pathologies. We describe a case in which a 52-year-old perimenopausal woman presents with a vulvar mass. After an initial biopsy and later excision, the myofibroblastic lesion was noted to have areas of differing cellularity, with compact nodule formations at the periphery. Immunohistochemical staining showed lesional cells to be positive for desmin, estrogen receptor, progesterone receptor, and smooth muscle actin, and negative for CD34, ALK-1, myogenin, caldesmon, S100, and wide spectrum (Oscar) cytokeratin. Desmin is generally negative in this lesion type, but the positivity in this case was considered to be secondary to the origin of the myofibroblastic cells of the vulva. The morphologic pattern and immunophenotype favored a diagnosis of nodular fasciitis, however, the degree of hypercellularity and desmin positivity warranted further analysis. The diagnosis was supported with fluorescence in situ hybridization that demonstrated USP6 gene rearrangement. This highlights the necessity in certain challenging cases for ancillary molecular and/or cytogenetic analysis.

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).

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Cranial fasciitis presenting as an intracranial mass in a 10-year-old girl

Cranial fasciitis is a mass-forming lesion of myofibroblastic proliferation of the skull and overlying soft tissue and occurs most frequently in pediatric patients. Cranial fasciitis has the same histological features as nodular fasciitis, which appears in the subcutaneous tissue in other parts of the body. Cranial fasciitis can involve the outer table of the skull, and it occasionally extends through the skull to form a mass involving both soft tissue and the epidural space. Intracranial cranial fasciitis without a soft tissue mass is extremely rare. Here, we report a case of a 10-year-old girl who presented with a massive intracranial mass that caused midline shift of the brain. The lesion showed focal areas of osseous metaplasia and a cytogenic abnormality of t(17;18)(q25∶q12.2) that have not yet been reported.

Nodular fasciitis: a novel model of transient neoplasia induced by MYH9-USP6 gene fusion

Nodular fasciitis (NF) is a relatively common mass-forming and self-limited subcutaneous pseudosarcomatous myofibroblastic proliferation of unknown pathogenesis. Due to its rapid growth and high mitotic activity, NF is often misdiagnosed as a sarcoma. While studying the USP6 biology in aneurysmal bone cyst and other mesenchymal tumors, we identified high expression levels of USP6 mRNA in two examples of NF. This finding led us to further examine the mechanisms underlying USP6 overexpression in these lesions. Upon subsequent investigation, genomic rearrangements of the USP6 locus were found in 92% (44 of 48) of NF. Rapid amplification of 5'-cDNA ends identified MYH9 as the translocation partner. RT-PCR and direct sequencing revealed the fusion of the MYH9 promoter region to the entire coding region of USP6. Control tumors and tissues were negative for this fusion. Xenografts of cells overexpressing USP6 in nude mice exhibited clinical and histological features similar to human NF. The identification of a sensitive and specific abnormality in NF holds the potential to be used diagnostically. Considering the self-limited nature of the lesion, NF may represent a model of 'transient neoplasia', as it is, to our knowledge, the first example of a self-limited human disease characterized by a recurrent somatic gene fusion event.

Pseudosarcomatous Soft Tissue Lesions: A Review

Pseudosarcomatous soft tissue lesions are potential pitfalls to both clinicians and pathologists due to their clinical presentation, resemblances to malignant lesions and their rarity. They also have a wide range of differential diagnosis histologically due to their relatively non-specific morphology and natural history of evolving features. The difficulty can be exacerbated by samples obtained from curettings or small biopsies as the architecture of the lesion is very helpful in pointing to the correct diagnosis. Familiarity with these entities is needed to avoid misdiagnosis and unnecessarily radical surgery. Despite recent advances in immunohistochemistry and genetic studies, their diagnosis still rest primarily on a combination of clinical history, radiological findings and histologic morphology.

Myofibroblastic sarcoma vs nodular fasciitis: a comparative study of chromosomal imbalances

We investigated the molecular cytogenetic features in myofibroblastic sarcoma (MS) to gain insight into the nature of the controversial entity. DNA copy number changes were analyzed by comparative genomic hybridization in 29 cases of MS and 5 cases of nodular fasciitis. The characteristic chromosomal imbalances in MS were gains at 1p11 --> p36.3 (19/29 [66%]), 12p12.2 --> p13.2 (13/29 [45%]), 5p13.2 --> p15.3 (9/29 [31%]), and chromosome 22 (8/29 [28%]) and loss at 15q25 --> q26.2 (7/29 [24%]). In contrast, only 1 of 5 cases of nodular fasciitis showed genetic aberrations. The average number of aberrations in nodular fasciitis (0.4) was significantly lower than that in MS (5.4). Thus, MS displayed complex DNA copy number changes and shared no range of common chromosomal abnormality with nodular fasciitis, indicating that distinct genetic pathways may be involved in the development of these entities.

Classification and pathology

Soft tissue tumors are a heterogeneous group of benign and malignant processes. Some are assumed to be reactive; others are clearly neoplastic. Because of their rarity, they frequently pose diagnostic problems for surgical pathologists. Accurate diagnosis of these tumors is enhanced by knowledge of the clinical features of the given lesions and, at times, by application of immunohistochemical and molecular techniques. In this article the lesions are described essentially in accordance with the World Health Organization classification.

Novel karyotypes in giant cell-rich lesions of bone

Giant cell-rich lesions of bone, including giant cell tumor of bone, giant cell reparative granuloma (GCRG), and aneurysmal bone cyst (ABC), may have overlapping clinical, radiologic, and histopathologic features. In fact, GCRG and solid ABC are currently differentiated solely based on skeletal location. Prior cytogenetic studies have reported that telomeric associations are present in the majority of giant cell tumors of bone, whereas translocations involving 16q22 and/or 17p13 are characteristic of ABCs. There is only one previously published karyotype of a GCRG, which revealed a reciprocal translocation, t(X;4)(q22;q31.3). We report 3 cases of giant cell-rich bone lesions with novel karyotypes: one lesion located in the first metacarpal, a typical location for GCRG, was histologically consistent with a giant cell tumor and showed the following karyotype [46,XX,inv(2)(p13q21),t(inv2;11)(q21;q13)]; the second lesion, also a giant cell tumor of bone, in the sacrum showed the following karyotype [46,XX,r(9)(p24q34)[cp7]/46,idem,?r(16)(p13.3q24)[cp10]/46,XX]. The third lesion, a hard palate mass, had the histopathologic features of a GCRG and a karyotype showing a reciprocal translocation, 46,XY,t(2;10)(q23;q24). These findings suggest that at least a subset of GCRGs may be neoplastic and that these lesions differ cytogenetically from classic giant cell tumors of bone or solid ABC, although the latter entity is otherwise indistinguishable from reparative granuloma. Further cytogenetic characterization of giant cell-rich bone lesions may improve the utility of karyotyping as a tool in their differential diagnosis and may shed light on the pathogenetic relationship between these lesions.

A gene expression signature that distinguishes desmoid tumours from nodular fasciitis

Nodular fasciitis (NF) is a rapidly growing cellular mass composed of fibroblasts/myofibroblasts, usually localized in subcutaneous tissues, that typically undergoes fibrosis and almost never recurs. Desmoid tumours (DTs) are rare forms of fibroblastic/myofibroblastic growth that arise in deep soft tissues, display a propensity for local infiltration and recurrence, but fail to metastasize. Given that both entities are primarily fibroblastic/myofibroblastic lesions with overlapping histological features, their gene expression profiles were compared to identify differentially expressed genes that may provide not only potential diagnostic markers, but also clues as to the pathogenesis of each disorder. Differentially expressed transcripts (89 clones displaying increased expression in DTs and 246 clones displaying increased expression in NF) included genes encoding several receptor and non-receptor tyrosine kinases (EPHB3, PTPRF, GNAZ, SYK, LYN, EPHA4, BIRC3), transcription factors (TWIST1, PITX2, EYA2, OAS1, MITF, TCF20), and members of the Wnt signalling pathway (AXIN2, WISP1, SFRP). Remarkably, almost one-quarter of the differentially expressed genes encode proteins associated with inflammation and tissue remodelling, including members of the interferon (IFN), tumour necrosis factor (TNF), and transforming growth factor beta (TGF-beta) signalling pathways as well as metalloproteinases (MMP1, 9, 13, 23), urokinase plasminogen activator (PLAU), and cathepsins. The observations provide the first comparative molecular characterization of desmoid tumours and nodular fasciitis and suggest that selected tyrosine kinases, transcription factors, and members of the Wnt, TGF-beta, IFN, and TNF signalling pathways may be implicated in influencing and distinguishing their fate.

Clinico-pathologic correlations of myofibroblastic tumors of the oral cavity: 1. Nodular fasciitis

BACKGROUND

Nodular fasciitis (NF), a soft tissue lesion mainly composed of myofibroblastic cells, is well documented in various body locations however, in the oral cavity it is rare. The NF has non-specific histologic characteristics that might result in misdiagnosis and mistreatment. The aim of the study was to analyze clinico-pathologic correlations of NF occurring in the oral cavity.

METHODS

A total of 36 cases of oral NF were analyzed including review of the English language literature and five new cases from our files.

RESULTS

Oral mucosa NF was found to peak in the fourth and fifth decades, which is a decade later than NF occurring in other sites of the body. The most common locations were the buccal mucosa (52.8%) and the lips (16.7%). Duration of lesions ranged from 3 days to 2 years, with approximately 61% being present for more than a month, which is longer than the duration of NF from other body locations. Histologically, oral NF showed varying degrees of cellularity and frequently contained myxomatous areas, and often demonstrated local infiltration into adjacent tissues. However, the myofibroblastic, spindle-shaped lesional cells were uniform and lacked any major signs of atypia. Mitotic figures, characteristically abundant in NF lesions throughout the body, ranged from absent to moderately high in oral NF cases. Treatment modality of choice was complete surgical excision. Recurrence was reported for only one case. Extensive, mutilating surgical procedures for oral mucosa NF are unnecessary, since lesions resolve even when surgical margins are partly involved.

CONCLUSIONS

The NF should be included in the clinical differential diagnosis of superficial and deep soft tissue masses of the oral cavity, especially of the buccal mucosa. Histopathologically, NF should be differentiated from other spindle cell lesions, mainly myofibroma, neurofibroma, fibrosarcoma, solitary fibrous tumor, fibromatosis and fibrous histiocytoma.

Bizarre parosteal osteochondromatous proliferation with a t(1;17) translocation

Bizarre parosteal osteochondromatous proliferation (BPOP) is a benign lesion that tends to recur repeatedly. Histologically, BPOP contains three components (cartilage, bone, and spindle cells) in differing amounts. The histological findings of BPOP are similar to those of florid reactive periostitis (FRP) and subungual (Dupuytren's) exostosis. Some authors have postulated that all of these conditions are reactive proliferative lesions representing different phases of reactive processes. Whether BPOP is a reactive proliferative lesion or a neoplastic lesion, however, remains controversial. Recently, a t(1;17)(q32;q21) translocation in BPOP was detected using chromosome banding and fluorescence in situ hybridization (FISH) analyses. Here, we describe a 39-year-old Japanese female with BPOP arising in the proximal phalanx of her third toe. A cytogenetic analysis revealed a t(1;17)(q 42;q23) translocation. The breakpoints in this case are located close to those of previously reported cases. These results suggest that t(1;17) is a distinct translocation of BPOP and that BPOP is a neoplastic lesion, rather than a reactive proliferative process.

Epithelioid hemangioma of the penis: a clinicopathologic and immunohistochemical analysis of 19 cases, with special reference to exuberant examples often confused with epithelioid hemangioendothelioma and epithelioid angiosarcoma

Epithelioid hemangiomas of the penis are very rare. To date, less than 10 examples have been reported in the English language literature. In this report, we describe the clinical, histopathologic, and immunohistochemical findings in 19 cases retrieved from our files. The patients ranged in age from 23 to 75 years (median age, 45 years) at the time of initial surgical resection. Seventeen patients presented with a solitary mass, and two presented with two separate, but closely approximated, lesions. The process involved the glans penis (n = 3), shaft (n = 11), base of the penis (n = 2), or penis, not otherwise specified (n = 3). The lesions ranged in size from <0.5 to 2.5 cm (median size, approximately 1.2 cm) in greatest dimension. Eleven examples were specifically noted to be dorsally located, and only one was stated to be ventral. Localized pain or tenderness was the most common complaint, documented in 12 cases. The preoperative duration of the lesions ranged from 5 days to 1 year (median 4.5 months). Microscopically, all examples contained a tumefactive proliferation of epithelioid endothelial cells, often in a nodular or lobular configuration and associated with an inflammatory infiltrate containing lymphocytes and eosinophils. In 14 cases, the vascular proliferation was associated with a small arterial segment, sometimes with mural damage and frequently (n = 13) with intraluminal epithelioid endothelial cells. Based on the growth pattern of the epithelioid endothelial cells, 13 cases were considered "typical," and six were considered exuberant or "atypical." The latter examples had a prominent centrally located zone where nests or sheet-like aggregates of epithelioid endothelial cells did not form discrete vessels. Immunohistochemical data are available for 15 tumors. The epithelioid endothelial cells usually had strong reactivity for CD31, lesser reactivity for factor VIIIrAg, and minimal reactivity for CD34. In 9 of 12 cases, a small number of epithelioid endothelial cells expressed keratins. In all cases tested, at least focal muscle-specific actin-positive myopericytic cells were present bordering the endothelial cells, and this was especially notable peripherally. Initial surgical intervention consisted of either a shave biopsy (n = 1), excisional biopsy (n = 2), or local excision (n = 16). A complete follow-up history is available for 12 patients, and incomplete follow-up information is available for an additional four patients. One patient developed a new epithelioid hemangioma at a site within the penis separate from the initial lesion, but no patient is known to have experienced a true metastasis or to have died of complications of this process. Optimal management appears to be complete local excision with periodic follow-up visits to monitor for local recurrence.

Parasagittal Cranial Fasciitis after Irradiation of a Cerebellar Medulloblastoma: Case Report

OBJECTIVE AND IMPORTANCE

Cranial fasciitis is a very rare, nontumoral lesion of the cranium with potential intracranial expansion typical of childhood. Radiotherapy has not been reported among the possible causes or factors associated with this condition. We present a case of cranial fasciitis in an 11-year-old patient previously admitted for cranial radiotherapy of a cerebellar medulloblastoma. Cytogenetic analysis revealed a pattern of chromosomal abnormalities suggestive of a radiation-induced lesion.

CLINICAL PRESENTATION

An 11-year-old patient, who had been treated previously with craniospinal radiotherapy for a medulloblastoma, presented with a tumor resembling a parasagittal meningioma.

INTERVENTION

At surgery, the tumor apparently had eroded the cranium and was deemed to originate from the external layer of the sagittal sinus. A distinct line of cleavage permitted total removal. Histological analysis was suggestive of cranial fasciitis. Cytogenetic analysis revealed the presence of a polyclonal karyotype in a background of nonclonal changes.

CONCLUSION

Cranial fasciitis should be included in the differential diagnosis of intracranial tumors infiltrating the cranium. Treatment of these lesions is easier than that of other parasagittal lesions because the sinus is compressed but not infiltrated. This case is associated with previous radiotherapy; thus, cranial fasciitis could be considered one of the more common radiation-induced lesions.

Cytogenetic findings in a case of nodular fasciitis of subclavicular region

We report a case of nodular fasciitis with a reciprocal translocation involving both homologues of chromosome 15 [46,XX,t(15;15)(q13;q25)]. This is the third case of nodular fasciitis with involvement of chromosome 15. Two genes that are involved in either wound healing and/or tumorigenesis have been mapped to chromosome 15. One of the genes, the keratinocyte growth factor or fibroblast growth factor 7 (KGF or FGF7) was mapped to the 15q22 region, which was involved in a cytogenetic rearrangement in one case of nodular fasciitis. KGF is implicated in wound healing, healing lung injuries and tumorigenesis of various cancers such as breast and prostate. The second gene involved is TRKC or NTRK3 mapped to the 15q25 region. TRKC is implicated in congenital fibrosarcoma, a benign proliferation of fibroblasts. The breakpoint and overexpression of the protein in our case further suggest a possible involvement of TRKC.

Clonal rearrangement of 15p11.2, 16p11.2, and 16p13.3 in a case of nodular fasciitis: additional evidence favoring nodular fasciitis as a benign neoplasm and not a reactive tumefaction

This article describes a case of nodular fasciitis with the karyotype 47,XY,+4/46,XY,add(15)(p11.2), t(16;16)(p13.3;p11.2). The presence of clonal chromosomal abnormalities in this case, as well as in three previously reported cases, indicates that nodular fasciitis is a benign neoplasm and not a reactive lesion.

Genetic and molecular abnormalities in tumors of the bone and soft tissues

BACKGROUND

Malignant transformation requires the accumulation of multiple genetic alterations such as chromosomal abnormalities, oncogene activation, loss of tumor suppressor genes, or abnormalities in genes that control DNA repair and genomic instability. Sarcomas are a heterogeneous group of malignant mesenchymal tumors of difficult histologic classification and strong genetic predisposition. This article provides a comprehensive review of the cytogenetic abnormalities observed in bone and soft-tissue tumors, emphasizing known downstream molecular changes that may play a role in oncogenesis.

METHODS

The database of the National Library of Medicine was searched for literature relating to genetic and molecular mechanisms in sarcomas in general and in each of the main tumor entities.

RESULTS

Recent techniques in chromosome analysis and molecular cytogenetics have improved our ability to characterize genetic changes in mesenchymal tumors. Some changes are so characteristic as to be virtually pathognomonic of particular histologic types, while others are complex, difficult to characterize, and of unknown relevance to pathogenesis. The implications to the cell of some of these abnormalities are now being recognized.

CONCLUSIONS

The study of sarcomas will benefit from the information derived from genetic studies and translational research. The human genome project and new methodologies, such as computer-based DNA microarray, may help in the histogenetic classification of sarcomas and in the identification of molecular targets for therapy.