A PHF1-TFE3 fusion atypical ossifying fibromyxoid tumor with prominent collagenous rosettes: Case report with a brief review

Ossifying fibromyxoid tumor (OFMT) is a rare mesenchymal neoplasm of uncertain line of differentiation that can be subdivided into typical, atypical, and malignant tumors. Cytogenetically, OFMT is characterized by recurrent gene rearrangement involving PHF1 in up to 85% of cases. The most common PHF1 fusion partner is EP400, present in approximately half of cases. Most recently, a novel fusion of PHF1-TFE3 was identified in about 10% of PHF1-rearranged OFMTs. Herein, we report a unique case of PHF1-TFE3 fusion atypical OFMT with prominent collagenous rosettes. A 50-year-old male patient presented with a slowly growing, painless mass in the right foot for 4 years. Gross examination showed a 3.5-cm, subcutaneous well-circumscribed, lobulated mass. Microscopic examination revealed a well-demarcated but un-encapsulated tumor without a peripheral bony shell. The neoplasm was composed of mildly atypical spindle to ovoid cells with increased mitosis (2 mitoses per 10 high-power fields) arranged in a multinodular manner within a fibromyxoid stroma, which contained numerous small, irregular collagenous rosettes surrounded by radiating growth of tumor cells. The neoplastic cells were diffusely positive for TFE3 and CD10. RNA sequencing revealed an in-frame fusion between PHF1 exon 12 and TFE3 exon 7. Subsequent Fluorescence in-situ hybridization analyses demonstrated positive for rearrangements of both the PHF1 and TFE3 loci. The patient was free of disease at 63 months' follow-up. Our case exhibits atypical features and prominent collagenous rosettes, expanding the morphological spectrum of OFMT with PHF1-TFE3 fusion.

Round cell tumor with a myxoid matrix harboring a PHF1-TFE3 fusion: Myoepithelial neoplasm or ossifying fibromyxoid tumor?

Myoepithelial tumors arising in soft tissue are uncommon and mostly manifest a benign clinical course, although a malignant form does exist. An EWSR1 gene rearrangement is a common event in these tumors. Ossifying fibromyxoid tumor, a rare soft tissue neoplasm of uncertain differentiation, may have overlapping histologic and immunophenotypic features with myoepithelial tumors, but frequently harbors a PHF1 gene rearrangement. Interestingly, a PHF1-TFE3 fusion has been recently reported in both entities. Here we report a case of a malignant soft tissue tumor demonstrating myoepithelial differentiation and harboring a PHF1-TFE3 fusion. Despite being slow-growing and lacking significant cytologic atypia at initial presentation, the patient deteriorated rapidly with local recurrence and distant metastases. A discussion of the potential clinicopathologic implications of a PHF1-TFE3 fusion in these entities is also developed.

Ossifying fibromyxoid tumor of soft tissue: A case report with review of literature

Introduction and importance

The ossifying fibromyxoid tumor of soft tissue is a rare tumor of intermediate differentiation and uncertain lineage that occurs in adults mostly in the extremities and the trunk.

Presentation of case

we present a case of 57 year-old man presenting with a right scapular mass. It was a subcutaneous and painless mass that was largely excised. The diagnosis of ossifying fibromyxoid tumor of the right shoulder was made. The follow up of 1 year was without recurrence and metastasis.

Clinical discussion

The ossifying fibromyxoid tumor of soft tissue is exceptional, microscopic diagnosis and management is challenging, considering the scarcity of the tumor.

Conclusion

More cases and retrospective studies are needed to understand the pathogenesis and to determine optimal treatment regimens.

Case report and literature review

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Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue tumor varing from benign to malignant according to histology.

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Preoperative diagnosis is challenging, the current case of OFMT mimicked a sebaceous cyst on ultrasound.

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Correlation of imaging and fine needle aspiration findings narrows the differential diagnosis of OFMT.

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All patients must undergo prolonged postoperative follow up to assess for recurrence or rarely metastasis.

Introduction

Ossifying fibromyxoid tumor (OFMT) is an uncommon soft tissue neoplasm, with malignant potential and unclear histogenesis. OFMT exhibits a spectrum of histopathologic features including benign (typical), atypical and malignant subtypes. To the best of our knowledge, about 300 cases have been reported worldwide. We present the first reported case from Qatar.

Presentation of case

A 36-year old Egyptian male, with no comorbidities was admitted electively as a day case for excision of left thigh suspected sebaceous cyst under local anesthesia. History, physical examination and soft tissue ultrasound imaging were unremarkable. Intraoperatively, the patient was found to have a hard-calcified mass adhering to the surrounding fascia which was excised en bloc. The histopathology result was of ossifying fibromyxoid tumor. The post-operative course along with 40 months follow-up were uneventful in terms of surgical complications and recurrence.

Discussion

OFMT has marked features in terms of cytology. Though it is difficult to diagnose preoperatively, it should be considered in tumors involving soft tissue that demonstrate prominent ossification and calcification.

Conclusion

OFMT is a rare soft tissue neoplasm, and should be considered as a differential diagnosis in any subcutaneous swelling with a bony component. All OFMT patients should undergo a long course of follow-up to rule out and assess any recurrence or metastasis in the malignant variants.

Response to isolated limb perfusion and chemotherapy with epirubicin plus ifosfamide in a metastatic malignant ossifying fibromyxoid tumor

Background

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm of uncertain lineage and intermediate biological potential. It is more common in middle-aged men, usually arising from the deep tissues of the extremities. It is now established that it is a translocation related tumor, most often marked by translocation of PHF1 gene. Surgery is the mainstay of treatment and proves usually curative, although, in rarer cases the disease shows malignant features and tendency to recur both locally and at distant sites. In such cases, no standard treatment exists.

Case presentation

We report on a case of malignant advanced OFMT of the hand with lung metastases responding to isolated limb perfusion with human recombinant tumor necrosis factor and melphalan and chemotherapy with epirubicin and ifosfamide.

Conclusions

To our knowledge, this is the first report of activity of soft tissue sarcoma-oriented chemotherapy in advanced OFMT.

Ossifying fibromyxoid tumor of the trunk mimicking hydatid cyst: A case report

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Ossifying fibromyxoid tumor (OFMT) is a rare lesion that generally occurs in the soft tissues of proximal limbs.

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OFMT most often presents as a single swelling arising from the subcutaneous soft tissues or skeletal muscles of the extremities. Multifocal presentation is exceedingly rare.

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Complete surgical excision should be performed to prevent local recurrence.

Introduction

Ossifying fibromyxoid tumor (OFMT) is a rare lesion that generally occurs in the soft tissues of proximal limbs, head or neck and presents as a slowly growing mass. Abdominal or trunk locations are extremely rare.

Presentation of case

We report a case of 50-year-old man who presented with a painless, slow growing epigastric mass for 5 years. Radiologic assessment revealed a well circumscribed median subcutaneous parietal mass lesion present in front of the xiphoid process suspicious of a calcified hydatid cyst. Diagnosis of OFMT was made on histopathological examination of the resected specimen.

Discussion

OFMT most often presents as a single swelling arising from the subcutaneous soft tissues or skeletal muscles of the extremities. Multifocal presentation is exceedingly rare. Radiologically, a peripheral shell of bone is seen in more than 50% cases. On MRI, myxofibrous stroma appears isointense to muscle on T1 and of intermediate to high signal intensity on T2. Surgical excision is the mainstay of treatment. Histologically, the tumor has a thick fibrous capsule with a complete or partial underlying layer of metaplastic woven or lamellar bone. Tumor is composed of uniform round, ovoid, or spindle-shaped cells arranged in nests and cords embedded in a variably myxoid and collagenous Alcian blue-positive stroma. On immunochemistry, the tumor cells are positive for S100 protein and desmin in 90% and 50% cases respectively.

Conclusion

OFMT is a rare soft tissue tumor with malignant potential often misdiagnosed as a benign lesion. Complete surgical excision should be performed to prevent local recurrence.

Ossifying fibromyxoid tumor: a study of 6 cases of atypical and malignant variants

Ossifying fibromyxoid tumors (OFMT) of soft parts are rare, slow-growing tumors that have potential for local recurrence and may metastasize. While OFMT originally was considered benign, several cases of malignant OFMT have been documented. There is no universally accepted risk stratification, although this study emphasizes the importance of utilizing histology, immunohistochemistry and FISH in establishing the diagnosis. Herein, we describe six cases of atypical and malignant OFMT with differences in morphologic features, 5 of which display the proposed morphological criteria for malignancy. The patients were mostly male (M=5, F=1) with an age range of 33-69 years. The tumors arose from the extremities (3 cases), the shoulder (1 case), the head and neck area (1 case), and the paraspinal area (1 case). One tumor had high grade and overtly sarcomatous changes, while another invaded the underlying clavicle. Two cases showed cytological atypia and necrosis. Fluorescence in situ hybridization (FISH) detected rearrangement of the PHF1 gene in 5 cases. All cases were positive for EAAT4 and actin by immunohistochemistry, while negative for desmin. Three tumors were immunoreactive for S100 protein. INI-1 immunohistochemical staining was conserved in all but 2 cases in which a mosaic loss of expression was noted. All but two patients are currently alive and free of disease.

Diagnostically Challenging Epithelioid Soft Tissue Tumors

In this article, we focus on the histologic features, differential diagnosis, and potential pitfalls in the diagnosis of epithelioid sarcoma, alveolar soft part sarcoma, clear-cell sarcoma, ossifying fibromyxoid tumor, and malignant extrarenal rhabdoid tumor. Numerous other soft tissue tumors also may have epithelioid variants or epithelioid features. Examples include epithelioid angiosarcoma, epithelioid malignant peripheral nerve sheath tumor, epithelioid gastrointestinal stromal tumor, and perivascular epithelioid cell tumor, among others.

Ossifying fibromyxoid tumor: morphology, genetics, and differential diagnosis

Ossifying fibromyxoid tumor (OFMT) is a soft tissue neoplasm of uncertain differentiation and intermediate (rarely metastasizing) biologic potential, with typical morphologic features, of an encapsulated, lobulated tumor comprising uniform polygonal cells within fibromyxoid stroma, which is surrounded by or contains metaplastic bone, classically as a peripheral rim of lamellar bone. Ossifying fibromyxoid tumor can arise at almost any site, although most frequently occurs within the extremities and trunk. Although most behave in a benign fashion, tumors can rarely show atypical or malignant features. It is now established that OFMTs represent translocation-associated tumors, with up to 85% associated with recurrent gene rearrangements, mostly involving the PHF1 gene (including in typical, atypical, and malignant neoplasms), with EP400-PHF1 in approximately 40% of tumors, and ZC3H7B-BCOR, MEAF6-PHF1, and EPC1-PHF1 fusions also described. Correct diagnosis is clinically important to ensure correct treatment and prognostication, both to avoid overdiagnosing OFMT as a malignant neoplasm such as osteosarcoma and also because of the propensity for aggressive behavior in a small number of OFMT. We review OFMT, with emphasis on the morphologic spectrum, recent molecular genetic findings, and the differential diagnosis.

Chondro-Osseous Lesions of Soft Tissue

Soft tissue lesions can contain bone or cartilage matrix as an incidental, often metaplastic, phenomenon or as a diagnostic feature. The latter category includes a diverse group ranging from self-limited proliferations to benign neoplasms to aggressive malignancies. Correlating imaging findings with pathology is mandatory to confirm that a tumor producing bone or cartilage, in fact, originates from soft tissue rather than from the skeleton. The distinction can have dramatic diagnostic and therapeutic implications. This content focuses on the gross, histologic, radiographic, and clinical features of bone or cartilage-producing soft tissue lesions. Recent discoveries regarding tumor-specific genetics are discussed.

A rare soft tissue tumor located in the trunk: Ossifying fibromyxoid tumor

Ossifying fibromyxoid tumor (OFMT), a rare soft tissue tumor, is generally located in the extremities with a distinct morphology characterized by bland, small cells lying in a fibromyxoid stroma and a peripheral rim of the lamellar bone. These tumors mostly express Leu-7, neuron specific enolase in addition to S-100 and vimentin. Some tumors may have malignant cytological features with aggressive behavior but even in classical morphology, recurrence or metastasis can be detected. Thus, the outcome of the tumor remains a mystery and depends on the different results detected during the follow up. Herein, we report a case of OFMT regarding this entity in the differential diagnosis of subcutaneous masses.

Atypical ossifying fibromyxoid tumor unusually located in the mediastinum: report of a case showing mosaic loss of INI-1 expression

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue tumor. OFMT mostly arises in subcutaneous tissue or skeletal muscle of the extremities and is extremely unusual in the mediastinum. OFMT is classified as typical, atypical, or malignant as tumor aggressiveness increases. Herein, we presented a case of atypical OFMT that developed in the mediastinum of a 43-year-old woman. Because of its predominant hypercellular area and some tumor cells with high nuclear grade, it was not a typical OFMT. However, it did not have a sufficient number of mitotic figures to be classified as malignant. Hence, we classified it as atypical OFMT with some apparent characteristic features of OFMT, such as the presence of spicules of bone at the periphery of the tumor. Upon immunohistochemistry, it was positive for vimentin, S-100 protein, and CD10, which was consistent with a diagnosis of OFMT. Particularly noteworthy was the mosaic loss of INI-1 expression. Some OFMT and other exceptionally rare tumors have been reported to exhibit mosaic INI-1 loss. Inactivation of INI-1 gene and deregulation of PHF1 gene are thought to be involved in tumorigenesis of OFMT. Therefore, we speculated that the mosaic loss of INI-1 observed in the present case might also be related to a kind of abnormality of INI-1 as was reported previously.

Ossifying fibromyxoid tumor (OFMT) - A rare cause of a painful thumb

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Ossifying fibromyxoid tumors (OFMT) is a rare but possible cause of a painful digit.

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These are part of the spectrum of sarcomas.

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They should be managed in a multidisciplinary environment with adequate follow up to detect recurrences.

INTRODUCTION

Ossifying fibromyxoid tumor (OFMT) is an uncommon soft tissue and bone neoplasm with just over 100 cases being reported in the literature. They present as small, slow-growing asymptomatic subcutaneous nodules in the soft tissues of the trunk and extremities.

PRESENTATION OF CASE

We present a case of a 25-year-old, right hand dominant gentleman who complained of a seven-year history of pain and discomfort in the dorsal aspect of the right thumb. He was unable to move his interphalangeal joint (IPJ) but had good function otherwise. Examination revealed a localized tender swelling over the dorsal aspect of the IPJ. The thumb was fixed in extension. X-ray revealed marked abnormal soft tissue swelling around the interphalangeal joint, cystic abnormalities and new bone formation. Biopsy showed fibrous tissue containing nodules of tumor with cells in a myxoid background, rounded and histiocytoid to elongated and spindle shaped. CD57, type IV collagen, smooth muscle actin were found and CD56 and EMA were focally positive.

These were in keeping with ossifying fibromyxoid tumor with an atypical immunophenotype.

DISCUSSION

The tumor was formally excised with the flexor pollicis longus tendon. A two-month review revealed his pain had settled. As the tumor had an atypical immunophenotype he was referred to the regional sarcoma team.

CONCLUSION

OMFT can present with atypical clinical, radiological and histological features. It is managed in a multidisciplinary setting and often requires lifetime follow up to detect a recurrence given the uncertain nature of these lesions.