Eosinophilic fasciitis: unraveling the clinical tapestry of a rare case and review of literature.

Eosinophilic fasciitis (EF) remains a diagnostic challenge due to its rarity and resemblance to scleroderma. This case report aims to provide a cohesive exploration of EF's clinical nuances, emphasizing the importance of accurate diagnosis and effective management. A 52-year-old male developed bilateral forearm and calf hardening, along with erythema, pruritus, and pain four months prior to the presentation in our Clinic. The symptoms initially debuted bilaterally in the forearms and progressed to involve the calves, distal arms, and thighs. Clinical examination revealed symmetrical plaques on forearms and calves, featuring erythematous, hyper, and hypopigmented elements extending proximally, a positive "groove sign" and a moderate difficulty in knee joint flexion. Despite these findings, the patient was generally in good condition, without any other notable clinical signs. Initial laboratory findings showed slightly increased percentual eosinophil levels, elevated C-reactive protein (CRP), normal erythrocyte sedimentation rate (ESR), and negative antinuclear and scleroderma specific antibodies. Magnetic resonance imaging (MRI) demonstrated enhanced fascial signal and thickening while the fascia-muscle biopsy revealed marked edema and inflammatory lymphoplasmacytic infiltrate, consistent with the diagnosis of EF. The patient showed a favorable response to systemic corticosteroids. EF predominantly affects males aged 30 to 60 and is characterized by a sudden onset and unclear etiological factors. Differential diagnosis requires careful exclusion of scleroderma and other mimicking conditions. Diagnostic modalities such as skin-muscle biopsy and MRI reveal characteristic findings like inflammatory infiltrate and fascial thickening. Accurate diagnosis and differentiation from scleroderma are crucial, with early intervention involving glucocorticoids and immunosuppressive agents improving long-term outcomes.

Recurrent USP6 rearrangement in a subset of atypical myofibroblastic tumours of the soft tissues: low-grade myofibroblastic sarcoma or atypical/malignant nodular fasciitis?

AIMS: Low-grade myofibroblastic sarcoma (LGMS) is a rarely metastasizing myofibroblastic tumour mostly affecting extremities and the head and neck of adults. Histologically, it shows long infiltrative fascicles of spindle cells with moderate nuclear atypia. By immunohistochemistry, it stains positive for smooth muscle actin (SMA) and sometimes for desmin. To date, no recurrent genetic abnormalities have been described. Ubiquitin-specific peptidase 6 (USP6) gene rearrangement is typically found in some benign bone and soft-tissue tumours including nodular fasciitis (NF), among others. Nevertheless, rare cases of USP6-rearranged tumours resembling NF with atypical features have been reported. METHODS AND RESULTS: One index case of LGMS of the deltoid in a 56-year-old man presented the THBS2::USP6 translocation by RNA sequencing (Archer FusionPlex Sarcoma v2 panel). Further screening of 11 cases of LGMS using fluorescent in situ hybridization (FISH) analysis with a USP6 break-apart probe identified two additional cases. These cases were investigated with RNA-sequencing, and a RRBP1::USP6 translocation was detected in one. The other case was not assessable because of low-quality RNA. Noteworthy, rearranged LGMSs presented distinctive features including variable multinodular/plexiform architecture, prominent vasculature with occasional wall thickening, scattered osteoclast-like multinucleated giant cells, and peripheral lymphoid aggregates. CONCLUSION: Our findings support the notion that among soft-tissue neoplasms with fibroblastic/myofibroblastic phenotype, USP6 rearrangement is not limited to benign tumours, and warrants further investigation of genetic changes in myofibroblastic sarcomas.

"Bone in the penis" or fasciitis ossificans of the penis - a first time description of a pseudo-tumor at an extraordinary site.

BACKGROUND: Fasciitis ossificans is a rare subtype of nodular fasciitis, a benign soft tissue tumor with reactive characteristics. Due to its rapid growth, it is often misdiagnosed as a malignant tumor. While fasciitis ossificans commonly originates from the subcutaneous tissue and can appear throughout the body, it may also arise from extraordinary sites. CASE PRESENTATION: We report the first-ever documented case of fasciitis ossificans arising from the penis in a male patient who presented with a tumor on the glans penis. The tumor was surgically resected due to suspicion of penile cancer. Initial histopathological analysis led to a misdiagnosis of squamous cell carcinoma. However, pathological consultation ultimately confirmed the diagnosis of fasciitis ossificans of the penis originating from the glans penis by demonstrating ossification. CONCLUSION: This case underscores the importance of considering fasciitis ossificans in the differential diagnosis of soft tissue tumors, even in unusual locations such as penile soft tissue.

[A clinical case of piloleiomyoma]. / Klinicheskii sluchai piloleiomiomy.

The article describes a clinical case of a benign tumor from smooth muscle cells - piloleiomyoma. The incidence of leiomyoma in the skin is 3-5% of all leiomyomas. A 27-year-old patient applied to a medical institution with complaints about an intradermal formation in the ear region that occurred repeatedly within 5 months after surgical treatment. After the first surgical intervention, the patient was consulted in various medical organizations, where the following diagnoses were made: «nodular fasciitis¼, «smooth muscle tumor without signs of malignancy¼ and «non-epithelial spindle cell neoplasm¼. According to ultrasound examination, the formation with dimensions of 11×9×5 mm reached the mastoid process of the temporal bone and was characterized by increased internal blood flow. After surgical removal of the neoplasm, taking into account the difficulties of differential diagnosis, an immunohistochemical study was conducted. An accumulation of smooth muscle cells was detected in the surface layers of the dermis under the epidermis by the immunohistochemical study with the use of the marker SMA. A study on CD34 protein revealed a high density of blood capillaries and the absence of its expression in smooth muscle cells. The proliferative index (Ki-67) and mitotic activity (PHH-3) of cells was also studied. The index of proliferative activity was less than 2%, mitoses were isolated. Thus, the results of immunohistochemical study proved the conclusion of piloleiomyoma.

Ischemic fasciitis scalp-unusual presentation and location.

ABSTRACT: We report a case of ischemic fasciitis in a 34-year-old male patient who presented with hard swelling on the anterior aspect of the scalp measuring 5 × 4 cm. He gave a history of wearing a tight turban constantly for many years. The lesion initially presented as redness of the skin, which gradually became a nodular swelling over 2 years. A computed tomography (CT) scan showed conical solid soft tissue attenuation mass. The operative findings were suspicious of neoplasm. However, the microscopic findings were typical of ischemic fasciitis, that is, a zonal pattern with central hypocellular fibrinoid necrosis surrounded by more cellular areas containing prominent proliferating neovessels and fibroblasts resembling granulation tissue. Ischemic fasciitis of the scalp is extremely rare, the present case occurred as a result of ischemia continuously exerted due to wearing a tight turban. This case highlights the importance of eliciting relevant case history and avoids histological misinterpretation of this pseudo-neoplastic lesion.

Fasciitis ossificans: imaging features, histology, and differential diagnosis.

AIM: To describe the imaging features of fasciitis ossificans and its histopathological features. MATERIALS AND METHODS: Using a word search of existing pathology reports at the Mayo Clinic, six cases of fasciitis ossificans were identified. The clinical history, histology, and available imaging of the affected area were reviewed. RESULTS: Imaging consisted of radiographs, mammograms, ultrasound images, bone scintigraphs, computed tomography (CT), and magnetic resonance imaging (MRI) images. All cases demonstrated a soft-tissue mass. The characteristic MRI appearance was a T2 hyperintense enhancing mass with surrounding soft-tissue oedema. Peripheral calcifications were seen on radiographs, CT, and/or ultrasound. Histological sections showed distinct zonation, with nodular fasciitis-like zones of myofibroblastic proliferation, which merged with osteoblasts that rim the ill-defined trabeculae of woven bone and became continuous with the mature lamellar bone surrounded by a thin layer of compressed fibrous tissue. CONCLUSION: Imaging features of fasciitis ossificans are that of an enhancing soft-tissue mass located within a fascial plane with prominent surrounding oedema and mature peripheral calcification. Imaging and histology are that of myositis ossificans but occurring within the fascia. It is important that radiologists are aware of the diagnosis of fasciitis ossificans and appreciate its similarity to myositis ossificans. This is particularly important in anatomical locations with fascias but no muscle. Given the radiographic and histological overlap between these entities, nomenclature that encompasses both could be considered in the future.

Unravelling the USP6 gene: an update.

Ubiquitin-specific protease 6 (USP6) rearrangements have been identified in aneurysmal bone cyst, nodular fasciitis, myositis ossificans, fibro-osseous pseudotumour of digits and cellular fibroma of tendon sheath. These entities show clinical as well as histological overlap, suggesting they are all clonal neoplastic belonging to the same biological spectrum and referred to as 'USP6-associated neoplasms'. They all show a characteristic gene fusion formed by juxtaposition of the USP6 coding sequences to the promoter regions of several partner genes, leading to USP6 transcriptional upregulation.

Fascitis nodular en región maxilofacial. Un caso clínico / Nodular fasciitis in head and neck region. A case report

La fascitis nodular (FN) es una entidad rara que consiste en la proliferación benigna miofibroblástica de la fascia muscular. Se trata de un proceso de etiología desconocida. La presentación clínica habitual consiste en una tumoración de menos de 4 cm de diámetro, indolora, de consistencia dura y de rápido crecimiento. La localización en el territorio craneofacial es muy infrecuente (7-20 %). La fascitis nodular se puede confundir clínica e histológicamente con tumoraciones malignas, por lo que es muy importante un correcto diagnóstico. Presentamos el caso de un paciente varón de 79 años, que consulta por aparición de tumoración paramandibular, de consistencia dura y de dos meses de evolución, asintomática. Tras la realización de pruebas complementarias, el diagnóstico citológico fue de neoplasia mesenquimal con atipias sospechosa de malignidad, recomendándose estudio histológico. (AU)

Nodular fasciitis (NF) is a rare entity consisting of a benign myofibroblastic proliferation of the muscle fascia, a process of unknown etiology. The usual clinical presentation consists of a tumor of less than 4 cm in diameter, painless, of hard consistency and rapid growth. Localization in the craniofacial territory is very infrequent (7-20 %). Nodular fasciitis can be clinically and histologically confused with malignant tumors, so a correct diagnosis is very important. We present the case of a 79-year-old male patient who consulted for the appearance of an asymptomatic paramandibular tumor, with a hard consistency and two months of evolution. After performing complementary tests, the cytological diagnosis was mesenchymal neoplasm with atypia suspicious of malignancy, recommending histological study.In conclusion, an extremely rare giant-sized mucinous adenocarcinoma of the submandibular gland is presented. (AU)

Case report: Large-size intramuscular nodular fasciitis, a challenging histopathologic diagnosis confirmed by molecular detection of USP6 gene rearrangement: Case report and literature review.

The intramuscular subtype of nodular fasciitis (NF) is rare with lesions normally not more than 2 cm in size and characterized by pseudosarcomatous morphology. We report a case of a 27-year-old man with a large-size intramuscular NF. The patient came for treatment complaining of an increasingly enlarged mass in the left upper arm for 4 months. Magnetic resonance imaging (MRI) confirmed the presence of a well-defined tumor measuring 5 cm within the outer edge of the middle humerus. Microscopically, the neoplasm was rich in fibroblasts and myofibroblasts in an interlaced pattern with high mitotic index and evident multinuclear giant cells. Erythrocyte extravasation was easily seen in the stroma. The tumor border was infiltrative. Immunohistochemically, the tumor cells were positive for smooth muscle actin (SMA) and negative for cytokeratin, desmin, H-Caldesmon, CD34, S100, ALK, and ß-catenin. Fibrosarcoma was highly suspected by histopathological and immunohistochemical examination. Molecular detection demonstrated evidence of ubiquitin-specific peptidase 6 (USP6) gene rearrangement in this tumor. Based on the findings, the tumor was diagnosed as intramuscular NF. At 56 months after the initial surgery, the patient had recovered with no evidence of recurrence or metastasis. Large-size intramuscular NF is very rare and easily overdiagnosed as malignant tumor due to its obvious pseudosarcomatoid pathological features. USP6 gene rearrangement detection can effectively avoid this major misdiagnosis.

Eosinophilic Fasciitis: Current and Remaining Challenges.

Eosinophilic fasciitis (EF), defined as diffuse fasciitis with eosinophilia by Shulman in 1974, is a disease with unknown etiology and whose pathogenesis is still being researched. The diagnosis is based on the clinical aspects (skin induration with an "orange peel" appearance), the lab results (eosinophilia, increased inflammatory markers), the skin biopsy with the pathognomonic histopathological result, as well as the typical MRI changes. The treatment includes glucocorticoids and immunosuppressive drugs. Due to severe refractory cases, the treatment remains a challenge. EF is still a disease with potential for further research.

Multimodality imaging features of USP6-associated neoplasms.

Since the discovery of USP6 gene rearrangements in aneurysmal bone cysts nearly 20 years ago, we have come to recognize that there is a family of USP6-driven mesenchymal neoplasms with overlapping clinical, morphologic, and imaging features. This family of neoplasms now includes myositis ossificans, aneurysmal bone cyst, nodular fasciitis, fibroma of tendon sheath, fibro-osseous pseudotumor of digits, and their associated variants. While generally benign and in many cases self-limiting, these lesions may undergo rapid growth, and be confused with malignant bone and soft tissue lesions, both clinically and on imaging. The purpose of this article is to review the imaging characteristics of the spectrum of USP6-driven neoplasms, highlight key features that allow distinction from malignant bone or soft tissue lesions, and discuss the role of imaging and molecular analysis in diagnosis.

GLUT-1 expression is helpful to distinguish myxofibrosarcoma from nodular fasciitis.

Myxofibrosarcoma (MFS) is a fibroblastic/myofibroblastic neoplasm with a variably myxoid stroma. Histologically, MFS shows a wide spectrum of cellularity, pleomorphism and proliferative activity. Because of its variable morphology and lack of discriminatory markers, MFS can be difficult to distinguish from some benign soft-tissue tumors, especially nodular fasciitis (NF). Glucose transporter 1 (GLUT-1) is expressed in a variety of malignant mesenchymal tumors. In the current study, we evaluated GLUT-1 expression to determine its value in distinguishing MFS from NF. Tissue specimens from 14 MFS cases and 16 NF cases were sectioned and stained for GLUT-1 using immunohistochemistry. The percentage of GLUT-1-positive cells was scored as follows: 0 (no staining), 1+ (1-19%), 2+ (20-50%) and 3+ (>50%). Samples with a score of 1+ were defined as GLUT1-expressing samples. GLUT-1 expression was seen in all 14 MFS cases, whereas only 6 NF cases (37.5%) were positive for GLUT-1 and were scored 1+. Notably, 2-3+ GLUT-1 expression was found in 86% of MFS cases and 0% of NF cases. Our results indicate that GLUT-1 is a highly sensitive immunohistochemical marker for MFS and may be useful for the differential diagnosis of MFS and NF.

Histopathogenesis of bone- and soft-tissue tumor spectrum with USP6 gene rearrangement: multiple partners involved in the tissue repair process.

Primary aneurysmal bone cyst, nodular fasciitis, myositis ossificans and related lesions as well as fibroma of tendon sheath are benign tumors that share common histological features and a chromosomal rearrangement involving the ubiquitin-specific peptidase 6 (USP6) gene. The tumorigenesis of this tumor spectrum has become complex with the identification of an increasing number of new partners involved in USP6 rearrangements. Because traumatic involvement has long been mentioned in the histogenesis of most lesions in the USP6 spectrum and they morphologically resemble granulation tissue or callus, we attempted to shed light on the function and role USP6 partners play in tissue remodelling and the repair process and, to a lesser extent, bone metabolism.

Childhood proliferative fasciitis of the orbit mimicking sarcoma: a case report.

Proliferative fasciitis (PF) is a benign fibroblastic reaction with histological and clinical characteristics that overlap with those of malignant soft tissue tumors; thus, it is referred to as a pseudosarcomatous reaction. It continues to be an important cause of diagnostic error and overtreatment. The childhood PF subtype has some distinct histological and immunohistochemical characteristics that make differential diagnosis with malignant tumors even harder, especially with sarcoma. These proliferations generally occur in the lower limbs, and the periorbital region is a rare location of appearance. Here, we describe a case of childhood subtype PF in a 16-year-old girl located in the periorbital area. To the best of our knowledge, this is the first reported case of childhood subtype PF in the periorbital area, and the third case if PF subtypes are not taken into account.

Pathology Clinic: Nodular Fasciitis Involving the External Ear.

Nodular fasciitis is a rare, benign lesion characterized by the pseudosarcomatous proliferation of fibroblasts and myofibroblasts. Accurate diagnosis presents a unique challenge for otolaryngologists, as nodular fasciitis frequently mimics malignancy clinically; however, it can be distinguished from malignancy by subtle findings on pathology. A diagnosis of nodular fasciitis should be considered for any irregular or rapidly growing lesion of the head and neck area, as accurate diagnosis is particularly important to avoid overtreatment in cosmetically sensitive regions.

Nodular Fasciitis in the Cavity of Auricular Concha: A Case Report.

Nodular fasciitis (NF) has a low incidence, many classification subtypes and large histological variations. We describe a 17-month-old child who presented with a mass in the right cavity of auricular concha that was successfully cured by 2 procedures. In pediatric patients with fibroproliferative lesions, the possibility of NF should be excluded to avoid misdiagnosis and overtreatment.

[Solitary dorsal paravertebral tumor: radiological and histopathological characterization of a pediatric case of nodular fasciitis].

Nodular fasciitis is a benign soft tissue lesion with rapid fibroblastic or myofibroblastic proliferation, rarely observed in pediatric patients. Here, we present the case of a seven-year-old boy with no relevant medical records, in whom an asymptomatic dorsal tumor was incidentally identified. Magnetic resonance imaging showed a left dorsal paravertebral lesion with hypointensity on T1, hyperintensity on T2, peripheral contrast enhancement, and the so-called fascial tail sign. Complete surgical resection of the lesion was achieved. The histopathological study showed a proliferation of spindle or stellate cells with nuclei without atypia in a myxoid or collagenized stroma. The immunohistochemical profile showed positivity for smooth muscle actin, muscle-specific actin antibody HHF35, and calponin. The lesion was diagnosed as nodular fasciitis, an entity with broad and complex differential diagnosis. Presence of specific radiological signs and adequate immunohistochemical characterization of the lesion help perform an accurate diagnosis.

Nodular Fasciitis and Myxolipoma of the Larynx: A rare case report with brief literature review.

Nodular fasciitis (NF) is a peculiar, rapid-growing soft tissue lesion, typically appearing in subcutaneous tissue. Approximately 20% of NF occurs in the head and neck region, where they can involve any anatomic site. Laryngeal involvement, however, is quite rare. Lipoma is recognised as a slow growing, benign mesenchymal tumour; myxolipoma is a rare variant which has a prominent myxoid background. Laryngeal lipoma is infrequent, accounting for only 0.6% of all benign laryngeal lesions. We report a 61-year-old male patient with laryngeal nodular fasciitis coexisting with myxolipoma who presented to a tertiary care hospital in Ar Ramtha, Jordan, in 2020. Radiological and histological findings were indicative of laryngeal nodular fasciitis and myxolipoma was incidentally diagnosed. Following trans-oral debulking of the lesion the mass enlarged rapidly and the patient underwent a tracheostomy with complete mass excision and right partial laryngectomy through an open surgical approach. The patient had an uneventful recovery with no evidence of recurrence. The purpose of this report is to broaden the differential diagnosis of rapid-growing laryngeal masses that cause airway obstruction and to stress the significance of integrative interdisciplinary collaboration to establish an accurate diagnosis, thereby allowing proper management for benign pathologies and avoid futile aggressive treatment.