Primary pulmonary myxoid sarcoma in the interlobar fissure of the left lung lobe: a case report.

BACKGROUND: Primary pulmonary myxoid sarcoma (PPMS) is a rare, low-grade malignant tumor, constituting approximately 0.2% of all lung tumors. Despite its rarity, PPMS possesses distinctive histological features and molecular alterations, notably the presence of EWSR1-CREB1 gene fusion. However, its precise tissue origin remains elusive, posing challenges in clinical diagnosis. CASE DEMONSTRATION: A 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period. CONCLUSIONS: We report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.

Bilateral testicular myxosarcoma in a cryptorchid dog.

Myxosarcoma is a rare malignant mesenchymal neoplasm of soft tissues originating from fibroblasts. This report describes a case of bilateral myxosarcoma in a three-year-old cryptorchid dog. The animal was referred to the veterinary clinic because of the absence of testicles in the scrotum. Ultrasonography revealed two masses in the abdominal cavity with testicular echotexture. Exploratory laparotomy revealed the presence of cryptorchid testicles, and orchiectomy was recommended to treat the animal. Testicles were gray and reddish in color and enlarged with firm consistency. For histopathological analysis, testis fragments were fixed in 10% formalin and stained with hematoxylin and eosin and Alcian blue. Immunohistochemistry was performed using the following primary antibodies:1A4, HHF35, desmin, glial fibrillary acidic protein, CD31, S-100, vimentin, and Ki-67. Histopathological evaluation revealed the proliferation of fusiform and round cells associated with extensive areas of myxoid matrix. Neoplasms featured multinucleated giant cells, pleomorphism, karyomegaly, nuclear hyperchromasia, anisokaryosis, mitoses, and necrosis, with coarse chromatin and prominent nucleoli. Immunohistochemical analysis of vimentin- and the Alcian blue-positive cells confirmed the diagnosis of myxosarcoma. A high mitotic count and Ki-67 proliferative index suggests this myxosarcoma had a high degree of malignancy. To the best of our knowledge, this is the first case report of bilateral testicular myxosarcoma in a cryptorchid animal.

Metastatic cutaneous myxosarcoma in an adult horse.

A 25-year-old mixed-breed equine with separate nodular cutaneous lesions in the right thoracic limb (RTL) and right ventral abdominal region was admitted to a Veterinary Hospital in Belo Horizonte, Minas Gerais. Fine-needle aspiration cytology was performed on the RTL lesion and superficial cervical lymph node, and the results were suggestive of a malignant neoplasm known as myxosarcoma. Due to the unfavorable prognosis, the animal was euthanized. Based on the macroscopic and microscopic findings, the diagnosis of metastatic cutaneous myxosarcoma was confirmed. Although rare, this tumor should be considered as a differential diagnosis for cutaneous neoplasms in this species.

Obstructive cardiac myxosarcoma of the right ventricular outflow tract with pulmonary embolism and concurrent right atrial hemangiosarcoma in a dog.

A 13-year-old spayed female rottweiler crossbreed dog was presented with an 8-day history of abnormal gait and collapse associated with excitement or physical activity. A cardiac gallop was noticed on thoracic auscultation, and a 1st-degree atrioventricular block and sinus tachycardia were noted on an electrocardiogram. Echocardiography identified a hypoechoic, irregularly marginated luminal mass in the right ventricle at the level of the pulmonic valves. Postmortem gross examination confirmed the presence of a soft, polypoid, and botryoid mass (9 × 3 × 3 cm) with a smooth and glistening surface attached to the endocardium of the right ventricular outflow tract and extending to the pulmonary artery. The histological findings were consistent with the diagnosis of myxosarcoma with pulmonary embolism. In addition, the dog in this report had a right atrial hemangiosarcoma and a cutaneous hemangioma unrelated to her clinical findings. Key clinical message: Cardiac myxosarcomas are very rare neoplasms in dogs and concomitant primary heart tumors of different histogenesis are even rarer in dogs. To the authors' knowledge, this is the first report of coexistent myxosarcoma and hemangiosarcoma in the heart of a dog. Cardiac myxosarcomas should be considered in the differential diagnosis of intracavitary heart masses associated with signs of cardiac obstruction and failure.

Myxosarcome cardiaque obstructif de la voie d'éjection du ventricule droit avec embolie pulmonaire et hémangiosarcome auriculaire droit concomitant chez un chien. Une chienne croisée rottweiler stérilisée âgée de 13 ans a été présentée avec une histoire de démarche anormale et d'effondrement associés à l'excitation ou à l'activité physique depuis 8 jours. Un galop cardiaque a été noté à l'auscultation thoracique, un bloc auriculo-ventriculaire du 1er degré et une tachycardie sinusale ont été notés à l'électrocardiogramme. L'échocardiographie a permis d'identifier une masse luminale hypoéchogène et irrégulièrement marginalisée dans le ventricule droit au niveau des valvules pulmonaires. L'examen macroscopique post-mortem a confirmé la présence d'une masse molle, polypoïde et botryoïde (9 × 3 × 3 cm) avec une surface lisse et brillante attachée à l'endocarde de la voie d'éjection du ventricule droit et s'étendant jusqu'à l'artère pulmonaire. Les résultats histologiques concordaient avec le diagnostic de myxosarcome avec embolie pulmonaire. De plus, la chienne dans ce rapport présentait un hémangiosarcome auriculaire droit et un hémangiome cutané sans rapport avec ses résultats cliniques.Message clinique clé :Les myxosarcomes cardiaques sont des néoplasmes très rares chez le chien et les tumeurs cardiaques primaires concomitantes d'histogenèse différente sont encore plus rares chez le chien. À la connaissance des auteurs, il s'agit du premier rapport de myxosarcome et d'hémangiosarcome coexistant dans le cœur d'un chien. Les myxosarcomes cardiaques doivent être pris en compte dans le diagnostic différentiel des masses cardiaques intracavitaires associées à des signes d'obstruction et d'insuffisance cardiaque.(Traduit par Dr Serge Messier).

Sclerosing epithelioid fibrosarcoma of bone with hybrid features: clinicopathologic, radiologic, and molecular analysis of three cases.

Sclerosing epithelioid fibrosarcoma (SEF) occurring as a primary bone tumor is exceptionally uncommon. Even more rare are cases of SEF that show morphologic overlap with low-grade fibromyxoid sarcoma (LGFMS). Such hybrid lesions arising within the bone have only rarely been reported in the literature. Due to their variegated histomorphology and non-specific radiologic features, these tumors may pose diagnostic difficulties. Herein we describe three molecularly confirmed primary bone cases of sclerosing epithelioid fibrosarcoma that demonstrated prominent areas showing the features of LGFMS and with areas resembling so-called hyalinizing spindle cell tumor with giant rosettes (HSCTGR). Two patients were female and one was male aged 26, 47, and 16, respectively. The tumors occurred in the femoral head, clavicle, and temporal bone. Imaging studies demonstrated relatively well-circumscribed radiolucent bone lesions with enhancement on MRI. Cortical breakthrough and soft tissue extension were present in one case. Histologically the tumors all demonstrated hyalinized areas with SEF-like morphology as well as spindled and myxoid areas with LGFMS-like morphology. Two cases demonstrated focal areas with rosette-like architecture as seen in HSCTGR. The tumors were all positive for MUC4 by immunohistochemistry and cytogenetics, fluorescence in-situ hybridization, and next-generation sequencing studies identified EWSR1 gene rearrangements confirming the diagnosis in all three cases.Hybrid SEF is exceedingly rare as a primary bone tumor and can be difficult to distinguish from other low-grade spindled and epithelioid lesions of bone. MUC4 positivity and identification of underlying EWSR1 gene rearrangements help support this diagnosis and exclude other tumor types.

Pathological features of primary cardiac myxoid tumour in dogs: a review of 11 cases (2002-2022).

This report documents the pathological features of primary cardiac myxoid tumour (MT) in 11 dogs. Macroscopically, all the tumours were located in the tricuspid valve (TV), its septal leaflet being predominantly affected. Therefore, it appears that the TV is the most common site of occurrence for cardiac MT in dogs. Two gross anatomical types of canine valvular MT were evident. Seven of the 11 tumours were round or oval with a smooth or gently lobulated and glistening surface, while the other four were gelatinous, multilobulated and polypoid, with an irregular surface. Microscopically, in nine cases the tumours had an abundant myxoid matrix within which elongated spindle-shaped cells with no remarkable cytological atypia were sparsely embedded, suggesting a benign character (ie, myxoma). In the other two cases the tumours consisted of variably dense, haphazardly arranged, interlacing streams of anaplastic spindle-shaped or polygonal cells containing many mitotic figures, indicative of a malignant form of myxoma (ie, myxosarcoma). Isolated or clustered collections of myxoma cells (eg, cords, rings, syncytia) characteristic of human atrial myxoma were only rarely evident or lacking in all 11 cases, indicating that rarity or absence of such structural features may be specific to valvular MTs. Immunohistochemical findings were indicative of smooth muscle differentiation of the neoplastic cells. Tumour embolization to the intrapulmonary arteries and/or tumour implantation on the endocardium of the right heart chambers was evident only in the four cases of irregular-surfaced MT.

[Myxosarcoma in the cervical region in a teddy bear hamster (Mesocricetus auratus)]. / Myxosarkom in der Halsregion eines Teddy-Hamsters (Mesocricetus auratus).

This case report describes a rare case of a myxosarcoma in a 1-year-old teddy bear hamster presenting with a mass in the cervical region. The fine-needle aspiration cytology revealed high numbers of pleomorphic spindle-shaped cells found in a viscous mucinous background. The presumptive cytological diagnosis was malignant spindle cell neoplasia based on marked criteria of malignancy of the mesenchymal cell population. The abundant matrix in the background was suggestive of a myxosarcoma. The hamster died during surgery and a necropsy was performed. Histopathology was in complete agreement with the cytological report. Immunohistochemistry revealed the tumour to be vimentin positive with alcian-blue positive matrix and confirmed the presumptive diagnosis of a myxosarcoma. This case shows that fine-needle aspiration cytology can be utilized as a minimally invasive diagnostic tool in small mammals to classify mass lesions. However, so far little is known about the biological behaviour of myxosarcoma in the hamster as case descriptions are rare.

Innovative 3d-Printed Prosthesis In A Rare Case Of A Huge Mass Of Anterior Thoracic Wall - Low Grade Fibromyxoid Sarcoma (Lgfms).

The need for complete resection of chest wall tumors creates a huge challenge in terms of reconstructing the complex dynamics of the thorax. We are reporting a case of a low-grade fibromyxoid sarcoma (LGFMS) diagnosed in a young male, where the complete resection of the mass, sternum and parcially the pericardium was performed. Subsequently, a composite porous high-density polyethylene StarPore® prosthesis of the sternum and costal arches was used and the latissimus dorsi muscle free flap with skin graft was implanted over the sternum.

A cardiac malignant primary tumor: Left atrium myxosarcoma-A case report.

Myxosarcoma only accounts for a very small proportion of primary malignant tumors of the heart. The disease has no specificity in clinical manifestations or features on medical images. In this case study, we report about a middle-aged female patient afflicted with cardiac myxosarcoma. The initial transthoracic echocardiography of the patient revealed a cardiac myxoma. However, the postoperative histopathology confirmed the presence of a malignant cardiac myxosarcoma. Post-surgery follow-up imaging examinations revealed local recurrence in the left atrium as well as soft-tissue and bone metastases. The recurrent tumor and metastases were subsequently treated with chemotherapy and radiotherapy. However, the tumor did not respond to treatment and the disease progressed.

Differential diagnosis of myxoid soft tissue tumors. Experience in the Clinical University Hospital of Valencia

Soft tissue tumors with myxoid components are often a diagnostic challenge for the pathologist. We retrospectively reviewed 41 cases of soft tissue tumors with myxoid components diagnosed in our center over a five-year period. The most frequent diagnoses were myxofibrosarcoma and myxoid liposarcoma, followed by low-grade fibromyxoid sarcoma, low-grade fibromyxoid tumor and myxoid neurofibroma. Other diagnoses included were extraskeletal myxoid chondrosarcoma, myxoinflammatory fibroblastic sarcoma, low-grade myxoliposarcoma, myofibrosarcoma, fibromatosis, solitary fibrous tumor, non-ossifying variant of ossifying fibromyxoid tumor and ancient neurinoma with myxoid degeneration. Immunohistochemical and molecular biology studies contributed significantly to the diagnosis. We highlight the importance of immunohistochemistry for MUC4 in the diagnosis of low-grade fibromyxoid sarcoma, and underscore the need for molecular studies in selected cases. Furthermore, several myxoid neoplasms present specific chromosomal translocations, therefore molecular biology studies to detect fusion genes are usually essential for the diagnosis. When the characteristics of the sample are not adequate for molecular biology, or no specific alterations are described, an in-depth knowledge of the histology of these lesions is still necessary to decide the most accurate diagnosis.(AU)

Los tumores de tejidos blandos con un componente mixoide son con frecuencia un desafío diagnóstico para el patólogo. Revisamos retrospectivamente un total de 41 casos de tumores mixoides diagnosticados en nuestro centro durante un período de 5 años. Los diagnósticos más frecuentes fueron mixofibrosarcoma y liposarcoma mixoide, seguidos de sarcoma fibromixoide de bajo grado, tumor fibromixoide de bajo grado y neurofibroma mixoide. Otros diagnósticos incluyen condrosarcoma mixoide extraesquelético, sarcoma fibroblástico mixoinflamatorio, mixoliposarcoma de bajo grado, miofibrosarcoma, fibromatosis, tumor fibroso solitario, variante no osificante de tumor fibromixoide osificante y neurinoma antiguo con degeneración mixoide. Los estudios de inmunohistoquímica y de biología molecular contribuyeron significativamente al diagnóstico. Destacamos la importancia de la detección inmunohistoquímica de MUC4 para el diagnóstico de sarcoma fibromixoide de bajo grado y revisamos la necesidad de estudios moleculares en casos seleccionados. Además, algunas neoplasias mixoides presentan translocaciones cromosómicas específicas, por lo que el estudio molecular para detectar genes de fusión suele ser esencial para el diagnóstico. Cuando las características de la muestra no son adecuadas para el estudio de biología molecular, o no hay descritas alteraciones específicas, sigue siendo necesario un conocimiento profundo de la histología de estas lesiones para decidir el diagnóstico más apropiado.(AU)

Mixofibrosarcoma mandibular de bajo grado en un adulto / Low grade mandibular myxofibrosarcoma in an adult

Se describe el caso clínico de un paciente de 61 años de edad, con antecedente de buena salud, atendido en el St. Paul's Milennium Medical Hospital de Etiopía por presentar, desde hacía 2 años, una lesión en la encía marginal, con abombamiento de ambas corticales, que se extendía del primer premolar inferior derecho al izquierdo, por lo cual se decidió ingresarlo en el Servicio de Cirugía Maxilofacial para su estudio y tratamiento. Se trataba de un tumor poco frecuente y de gran tamaño, con amplia diseminación ganglionar hacia los niveles IV y V de ambas partes del cuello, de manera que se realizó el procedimiento quirúrgico. La evolución fue favorable en el posoperatorio inmediato y egresó de la institución 7 días después, pero continuó con radioterapia. Y seguimiento por consulta externa durante 24 meses después.

The clinical case of a 61-year-old patient, with a history of good health, treated at St. Paul's Milennium Medical Hospital in Ethiopia for presenting, for 2 years, a lesion in the marginal gum, with bulging of the gums, is described. both cortices, which extended from the lower right to the left first premolar, for which it was decided to admit him to the Maxillofacial Surgery Service for study and treatment. It was a rare and large tumor, with extensive lymph node dissemination to levels IV and V in both parts of the neck, so the surgical procedure was performed. The evolution was favorable in the immediate postoperative period and he was discharged from the institution 7 days later, but continued with radiotherapy. And follow-up by outpatient service for 24 months afterwards.

Low-grade Fibromyxoid Sarcoma of the Vulva and Vagina: Clinical, Pathologic, and Molecular Characterization of 7 Cases and Review of the Literature.

Low-grade fibromyxoid sarcoma (LGFMS) is a malignancy with propensity for late relapse that principally affects deep soft tissues of the extremities and trunk. Its occurrence in the lower female genital tract is rare, and thus it may not be always considered in the differential diagnosis. We describe the salient features of 7 vulvovaginal LGFMS identified in the authors' consultation files. Clinical information was obtained from referring pathologists. Archival slides were reviewed, and immunohistochemistry and fluorescence in situ hybridization were performed in cases with available material. Median age was 40 years (range, 34 to 58 y). Primary sites included vulva (n=6) and vagina (n=1). Tumors were 1.2 to 8.7 cm (median, 5.0 cm) in size and grossly circumscribed with firm to focally gelatinous cut surfaces. Microscopically, 5/7 had infiltrative edges. All tumors showed fibrous and myxoid areas, with lobulated myxoid foci in 5/7, comprising storiform, patternless, or (less often) fascicular arrangement of spindled to stellate cells with bland, slender to ovoid nuclei. In all cases, mitoses were <1/2.4 mm 2 , and necrosis was absent. Capillary "arcades" were seen in 3/7. Margins were positive in 3/6. Immunohistochemistry showed positive epithelial membrane antigen in 4/6 and MUC4 in 5/6. Fluorescence in situ hybridization detected FUS rearrangement in 5/7. Both tumors without FUS rearrangement were also negative for EWSR1 rearrangement. All 5 patients with available follow-up were alive and disease-free 10 to 150 months (median, 57 mo) after diagnosis. However, a review of vulvovaginal/pelvic LGFMS previously reported shows recurrences as late as 45 years after initial diagnosis. Pathologists need to be aware that LGFMS can arise in the vulvovaginal region. Tumor lobulation, capillary arcades, and positive MUC4 are helpful features distinguishing LGFMS from other bland myxoid spindle cell neoplasms in the lower female genital tract. Molecular testing can be useful in challenging cases. Complete excision is feasible for most vulvovaginal LGFMS. Long-term surveillance is required as local and/or distant spread can occur decades after diagnosis.

Acute Presentation of a High-Grade Myxofibrosarcoma Originating in the Thoracic Wall: A Case Report.

We report the first case of a patient with myxofibrosarcoma (MFS) who presented acutely with a rib fracture and developed a rapidly expanding loculated hemothorax after chest trauma. The patient was taken to the operating room for evacuation of hemothorax, and samples and biopsy specimens were taken for cytologic and pathologic examination. Final report with immunohistochemical staining showed a high-grade MFS. After the procedure, there was clinical and radiological improvement, and the patient was followed up as an outpatient. Myxofibrosarcoma is a very rare and aggressive connective tissue neoplasm with variable presentations. Surgical resection is the preferred treatment. Prompt diagnosis and adequate management of these tumors are important to reduce their high local recurrence and distant metastasis rates. Therefore, it is important to be aware of its common and uncommon presentations.

T-regulatory cells predict clinical outcome in soft tissue sarcoma patients: a clinico-pathological study.

BACKGROUND: Soft tissue sarcomas (STS) are generally considered non-immunogenic, although specific subtypes respond to immunotherapy. Antitumour response within the tumour microenvironment relies on a balance between inhibitory and activating signals for tumour-infiltrating lymphocytes (TILs). This study analysed TILs and immune checkpoint molecules in STS, and assessed their prognostic impact regarding local recurrence (LR), distant metastasis (DM), and overall survival (OS). METHODS: One-hundred and ninety-two surgically treated STS patients (median age: 63.5 years; 103 males [53.6%]) were retrospectively included. Tissue microarrays were constructed, immunohistochemistry for PD-1, PD-L1, FOXP3, CD3, CD4, and CD8 performed, and staining assessed with multispectral imaging. TIL phenotype abundance and immune checkpoint markers were correlated with clinical and outcome parameters (LR, DM, and OS). RESULTS: Significant differences between histology and all immune checkpoint markers except for FOXP3+ and CD3-PD-L1+ cell subpopulations were found. Higher levels of PD-L1, PD-1, and any TIL phenotype were found in myxofibrosarcoma as compared to leiomyosarcoma (all p < 0.05). The presence of regulatory T cells (Tregs) was associated with increased LR risk (p = 0.006), irrespective of margins. Other TILs or immune checkpoint markers had no significant impact on outcome parameters. CONCLUSIONS: TIL and immune checkpoint marker levels are most abundant in myxofibrosarcoma. High Treg levels are independently associated with increased LR risk, irrespective of margins.

Surgery Treatment Improved the Overall Survival Rate in Locoregional Myxoid Leiomyosarcoma than Other Myxosarcomas in the United States.

Myxosarcomas are rare malignant tumors of soft connective tissues, classified into various subtypes, including myxoid liposarcoma, myxoid chondrosarcoma, and myxoid leiomyosarcoma. In this study, we proposed to study the demographic, tumor characteristics, and overall survival rate and compared the treatment modalities between these cancers. Patient data collected based on locoregional metastasis presentation of the abovementioned tumors with a cutoff study of survival duration up to 10 years were obtained from the SEER database during 1975-2016. Our results indicated that elderly patients and females were more in locoregional myxoid leiomyosarcoma than myxoid liposarcoma and myxoid chondrosarcoma with locoregional metastasis. The white race represented the most patients who suffered from these cancers than other races. The heart is the primary site for the abovementioned cancers, in addition to the female genitals to the myxoid leiomyosarcoma. Myxoid liposarcoma and myxoid chondrosarcoma patients with locoregional metastasis were suffering from grade II, while locoregional myxoid leiomyosarcoma patients with blank grading were due to missed data. Surgery was the most common treatment modality in this study compared with radiotherapy and chemotherapy. Kaplan-Meier analysis showed a significant difference in survival time between the three subtypes by using histology, and myxoid leiomyosarcoma showed prolonged survival than others. Elderly, female, white, unknown grade, surgery, no radiation, and no chemotherapy variables were independent factors associated with overall survival among these cancers. Multivariate analysis also showed significant differences in overall survival between the three tumors by histology, and myxoid leiomyosarcoma was with a better prognosis than others. Multivariate analysis of locoregional myxoid leiomyosarcoma showed the statistical significance of black race, grade, and radiotherapy, indicating them as independent prognostic factors of locoregional myxoid leiomyosarcoma. We conclude that surgery was the primary treatment modality against these cancers than radiotherapy and chemotherapy. And the locoregional myxoid leiomyosarcomas showed a better prognosis and higher survival rate than locoregional myxoid liposarcoma and locoregional myxoid chondrosarcoma.

Low-grade fibromyxoid sarcoma of the parapharyngeal space: an unusual location.

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon soft-tissue malignancy. LGFMS preferentially affects trunks and extremities of young adults; however, occasional cases have been reported in different sites of head and neck region including oral cavity, larynx and oropharynx. LGFMS usually exhibit areas of collagenised and myxoid stroma with appearance of spindle cells in whorling pattern. It is a challenge to diagnose it accurately as most of the time it is misdiagnosed as benign neoplastic entity of spindle cells. There have been only few isolated cases of LGFMS reported in head and neck region and LGFMS originating from the parapharyngeal space has never been reported before. We recently experienced a case of low grade fibomyxoid sarcoma in parapharyngeal space of neck. LGFMS have the propensity to locally recur and to metastasise. Due to its rarity in head and neck region, there are no well-established treatment and follow-up guidelines.

Remarkable response to anti-PD1 immunotherapy in refractory metastatic high-grade myxofibrosarcoma patient: A case report.

INTRODUCTION: Myxofibrosarcoma (MFS) is a locally aggressive tumor and has the potential to be fatal because of distant metastasis. Immunotherapy targeting either programmed cell death protein 1 (PD-1) or programmed death ligand 1 (PD-L1) has recently shown a curative effect on multiple cancers including melanoma, non-small cell lung cancer, and renal cell carcinoma. Although the immunotherapy has been applied in sarcoma, there is little information about the efficiency to treat metastatic MFS. PATIENT CONCERNS: A 42-year-old male presented to the clinic with a mass in the left thigh. Mass resection and ligament replacement surgery were performed. DIAGNOSES: The patient was diagnosed as high-grade MFS (federation nationale des centres de lutte contre le cancer, Grade 3) with pulmonary metastasis. INTERVENTIONS: In the past few years, he was treated with surgery, chemoradiotherapy, and Anlotinib (an angiogenesis inhibitor), but the metastatic lesion continued to progress. About 40% to 50% of tumor cells in his pulmonary tissues were showed positive PD-L1 expression and his tumor mutational burden was 215Muts. Thus, he received Camrelizumab (PD-1 inhibitor). OUTCOMES: Six months after the initiating immunotherapy of Camrelizumab, the size of pulmonary lesions showed marked shrinkage, indicating a partial response. After a follow-up of 18 months, the patient remained in good condition without progressive disease. CONCLUSION: This case described here demonstrated that immunotherapy of PD-1 inhibitor is a promising treatment option for refractory MFS with PD-L1 positive or tumor mutational burden -high, which could contribute to effective tumor response.

Low-grade fibromyxoid sarcoma incidentally discovered as an asymptomatic mediastinal mass: a case report and review of the literature.

BACKGROUND: Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor characterized by bland histological features and aggressive clinical course. The most common anatomic locations of occurrence are the lower extremities, thorax, inguinal area, and upper limbs. Primary mediastinal sarcomas are even rarer. To the best of our knowledge, only seven cases of primary mediastinal LGFMS have been reported in the literature. Here, we report a case of primary mediastinal LGFMS. CASE PRESENTATION: A 26-year-old Pakistani man presented with fever and vomiting for the past 2 months. On a routine chest x-ray, a mediastinal mass was incidentally found. Computed tomography (CT) scan showed a large circumscribed lobulated soft tissue density mass lesion in an anterior mediastinum. Grossly, the resected mass measured 17.0 × 12.0 × 11.0 cm. The cut surface was gray white with a whorled-like appearance and foci of calcification and cystic changes. Histologically, a spindle cell lesion was seen with alternating myxoid and hyalinized areas. The shaped cells were arranged in bundles. Immunohistochemical staining showed positive reactivity patterns with MUC4 and focally for epithelial membrane antigen (EMA). The diagnosis was confirmed as LGFMS. The patient is free of symptoms and recurrence 22 months after the surgery. CONCLUSION: In conclusion, we report a rare case of primary mediastinal LGFMS in a young male patient that was discovered incidentally. Our patient is on regular follow-up to look for evidence of recurrence as these tumors are prone to recurrences.

Huge myxosarcoma arising from the greater omentum in a dog.

A 13-year-old intact Pomeranian bitch presented with a 2-month history of abdominal distension and anorexia. Ultrasonography and computed tomography revealed a large tumor in the abdominal cavity without metastases. The tumor was surgically resected and histopathologically characterized by spindle-shaped to atypical-shaped neoplastic cells with basophilic stroma in the omental adipose tissue. Immunohistochemistry revealed that the neoplastic cells were positive for vimentin but negative for cytokeratin, S-100 protein, and α-SMA. The bitch was diagnosed as a myxosarcoma arising from the greater omentum. Postoperatively, metronomic chemotherapy with cyclophosphamide and piroxicam was initiated. The tumor recurred on postoperative day 49. Although the bitch died 102 days after the initial examination, her general condition was maintained until death.