Leiomyosarcoma of bone arising in association with a bone infarct

Genomic Insights into High-Grade Infarct-Associated Bone Sarcomas

Sarcomas rarely develop in bones previously compromised by infarcts. These infarct-associated sarcomas often present as undifferentiated pleomorphic sarcomas (UPS), and their genetic characteristics are poorly understood. High-grade spindle cell/UPS of bone are typically treated with a combination of surgery and chemotherapy, similar to osteosarcoma. We conducted a detailed clinicopathologic and genomic analysis of six cases of intraosseous sarcomas arising from histologically and radiographically confirmed bone infarcts. We analyzed 523 genes for sequence-level mutations using next-generation sequencing with the TruSight Oncology 500 panel and utilized whole-genome SNP Microarray (OncoScan CNV) to detect copy number alterations and loss of heterozygosity (LOH). Genomic instability was assessed through Homologous Recombination Deficiency (HRD) metrics, incorporating LOH, telomeric allelic imbalance, and large-scale state transitions. FISH and immunohistochemistry validated the findings. The cohort included three men and three women, with a median age of 70, and tumors located in the femur and tibia. Five of the six patients developed distant metastases. Treatment involved surgery and chemotherapy or immune checkpoint inhibitors. Genomic analysis revealed significant complexity and high HRD scores, ranging from 32 to 57 (with a cut-off of 32). Chromosome 12 alterations, including segmental amplification or chromothripsis, were observed in four cases. Notably, MDM2 amplification, confirmed by FISH, was detected in two cases. Homozygous deletion of CDKN2A/B was observed in all six cases. Tumor mutational burden (TMB) levels ranged from 2.4 to 7.9 mutations per megabase. Notable pathogenic mutations included H3-3A mutations (p.G35R and p.G35W), and mutations in HRAS, DNMT3A, NF2, PIK3CA, POLE, and TP53, each in one case. These results suggest that high-grade infarct-associated sarcomas of bone, while sharing high levels of structural variations with osteosarcoma, may exhibit potentially less frequent TP53 mutations and more common CDKN2A/B deletions. This points to the possibility that the mutation spectrum and disrupted pathways could be distinct from conventional osteosarcoma.

Case report and literature review: Primary leiomyosarcoma of the bone in the trochanteric region of the femur

Background

Primary leiomyosarcoma of the bone (LMSB) is an extremely rare, invasive, and highly destructive primary osteosarcoma with limited treatment options and poor prognosis. Only a few case reports of LMSB have been described because of its rarity. Therefore, clinicians have a limited understanding of its diagnosis, treatment, and prognosis, and the final diagnosis depends on histopathological findings. In this report, we describe a rare case of primary LMSB in the trochanteric region of the femur. Reporting this case may increase the dissemination and understanding of information regarding LMSB and provide a reference for the diagnosis and treatment of similar cases.

Case presentation

A 63-year-old woman presented with pain and limited movement of the left hip, which had lasted for 3 months, with no history of trauma or illness. Plain radiography and computed tomography revealed a solitary osteolytic lesion in the trochanteric area of the left femur with focal cortical destruction. Magnetic resonance imaging findings suggested invasion of the lesion into the bone cortex, forming a soft tissue mass, although no distant positive findings were observed on a whole-body bone scan. A bone tumor puncture biopsy was performed to obtain a final diagnosis, and histopathological evaluation revealed left femoral intertrochanteric leiomyosarcoma, classified as G1T2M0 and staged as IB (extracompartmental low-grade malignant) according to the Enneking staging system. Thus, we performed extensive debridement and left hip arthroplasty. Postoperative chemotherapy was administered, and the patient was followed up for 4 years. Four years later, the patient's left hip pain had resolved, joint activity was good, and no signs of recurrence or distant metastasis of the bone tumor were noted.

Conclusion

For proximal femoral Enneking stage IB LMSB, extensive tumor resection combined with tumor prosthesis replacement may be an effective treatment method to prolong the patient's lifespan and to restore joint function.

Bone Infarcts and Tumorigenesis—Is There a Connection? A Mini-Mapping Review

(1) Background: Avascular necrosis (AVN) may affect every part of the bone. Epiphyseal infarcts are likely to be treated early because most are symptomatic. However, meta- and diaphyseal infarcts are silent and are diagnosed incidentally. Sarcomas developing in the necrotic bone are extremely rare, but they have been reported in the literature. (2) Methods: We conducted a mapping review of recent evidence regarding these malignancies. Methods: A mapping review using a systematic search strategy was conducted to answer research questions. We limited our research to the last ten years (2012–2022). (3) Results: A total of 11 papers were identified, including 9 case reports and 3 case series. The pathomechanism of carcinogenesis in AVN was not investigated to date. Histologically, most tumors were malignant fibrous histiocytoma. The prognosis is relatively poor, especially for patients with metastases, but adjuvant chemotherapy may increase short- and long-term survival. (4) Conclusions: Since AVN-related malignancies are sporadic, no prospective studies have been conducted. The majority of evidence comes from small case series. More research is needed to identify the risk factors that would justify follow-up of patients after bone infarcts at higher risk of developing a malignancy.

Bone infarct transformation into undifferentiated pleomorphic sarcoma in sickle cell disease: A case report

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Sickle cell disease pathophysiology.

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Natural progression of a pre-existing bone infarct.

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Malignant transformation of a pre-existing bone infarct.

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A rare case describing malignant transformation of a pre-existing bone infarct in a known sickle cell anemia patient into malignancy in specific undifferentiated pleomorphic sarcoma.

Introduction

Avascular necrosis of the bone is a very common finding in sickle cell disease (SCD). The malignant transformation of a pre-existing bone infarct is extremely rare, only few cases has been reported related to different etiologies one of which is SCD.

Presentation of case

40 years old male, known to have SCD, he presented as a case of avascular necrosis of the left proximal femur. Upon further investigations the lesion has transformed into undifferentiated pleomorphic sarcoma also known as Malignant Fibrous Histiocytoma (MFH).

Discussion

The exact mechanism of the malignant transformation of bone infarcts is not fully understood and yet to be investigated. Few cases were reported in literature of similar malignant transformation of a pre-exciting bone infarct and only one was linked to SCD.

Conclusion

In reporting this case we hope that further cases worldwide will be reported. A high index of suspicion should be present when encountering bone infarct lesion with an unusual course.

Primary leiomyosarcoma of the bone: a case report and a review of the literature

RATIONALE

Leiomyosarcoma (LMS) is a malignant sarcoma that can occur in different anatomic sites, including the bone, showing similar histological characteristics but heterogeneous clinical behavior and prognosis. Primary bone LMS was first described in 1965. It is a very rare sarcoma, accounting for <0.7% of all primary malignant bone tumors.

PATIENT CONCERNS

We report the case of a 52-year-old male with primary bone LMS who presented with a solitary osteolytic lesion with focal cortical destruction in the left clavicle, seen on an x-ray and subsequent computed tomography (CT) scan.

DIAGNOSIS

The multidisciplinary Osteoncology team of our institute planned a biopsy that revealed the presence of spindle and pleomorphic cells with a positive reaction for smooth muscle actin and desmin at immunohistochemical analysis, without the presence of cartilage or bone matrix. These results were consistent with a high-grade malignant LMS arising from the bone.

INTERVENTIONS

Complete surgical resection of the tumor was performed and a decision was made with the patient not to proceed with adjuvant chemotherapy or radiotherapy.

OUTCOMES

After more than 1 year of surgery, the patient is well, with no evidence of recurrent or metastatic disease. Follow-up is ongoing.

LESSONS

Little is known about the biology and clinical behavior of bone LMS due to its extreme rarity. A multidisciplinary team in a specialized center is needed for the optimal management of the disease. Surgery with a curative intent is the cornerstone of treatment of localized disease. No data are available about chemotherapy in neoadjuvant, adjuvant, or advanced settings. Further research is needed to identify more effective therapies.

Infarct-Associated Bone Sarcomas: Multimodality Imaging Findings

OBJECTIVE

The objective of our study was to characterize infarct-associated bone sarcoma and its imaging features.

MATERIALS AND METHODS

Our databases were searched for instances of sarcoma arising in association with osteonecrosis. Demographic and imaging data were recorded. The imaging studies of 258 patients with sarcomas were reviewed to determine whether underlying osteonecrosis was present. Radiographic and MRI studies of patients with bone infarction were reviewed to categorize the various appearances of infarction and to determine if sarcomas tended to arise in a particular pattern. A literature review was performed.

RESULTS

Nine infarct-associated bone sarcomas were found in eight patients: seven malignant fibrous histiocytomas (MFHs) and two osteosarcomas. All occurred in the femur or tibia; multifocal infarction was documented in all patients except one. Sarcomas were commonly associated with a so-called "mature"-type pattern of osteonecrosis-that is, with well-defined calcified margins. Osteolysis of infarct-associated MFHs was often overlooked at initial presentation and was often detected only after pathologic fracture. CT and MRI revealed cortical penetration in all cases; infarct margin disruption was evident, but preservation of fat within the infarct was typical. Increased radiotracer activity with relative central photopenia was characteristic of large infarct-associated bone sarcomas on scintigraphy. All lesions, including those treated at our institution and those found in the literature, were metaphyseal or diaphyseal, and although epiphyseal extension of sarcoma from a metadiaphyseal infarct was common, no purely epiphyseal lesions were encountered.

CONCLUSION

Radiologists must remain vigilant for this rare occurrence, especially in patients with new pain in an area of known bone infarction.

Intraosseous leiomyosarcoma arising in the epiphysis of the distal femur

Herein, we present a rare case of intraosseous leiomyosarcoma arising in the epiphysis of the distal femur and showing unusual radiographic features. A 44-year-old man presented with a pain in the left knee joint. Computed tomography revealed an intraosseous lesion with slightly increased attenuation and a thin marginal sclerotic rim in the femoral medial condyle. The signal of the lesion was hypointense on T1-weighted magnetic resonance (MR) images and hyperintense on fat-suppressed T2-weighted MR images. After gadolinium administration, the signal of the lesion was moderately and diffusely enhanced. The histological diagnosis of leiomyosarcoma was made based on a preoperative core biopsy specimen. Microscopic examination of the resected specimen revealed an ill-defined intraosseous tumor composed of proliferated atypical and mildly pleomorphic smooth muscle cells permeating among the bone trabeculae with only focal destruction of the bone trabeculae and low mitotic activity, indicating low grade leiomyosarcoma. The bone trabeculae at the periphery of the tumor were mildly thickened and anastomosed with a rim of an increased number of osteoblasts. Systemic examination showed no tumorous lesions in other anatomical sites. Leiomyosarcomas rarely present in the bone as a diffuse intertrabecular growth, even in low grade tumors.

Primary skeletal leiomyosarcoma

Leiomyosarcoma typically occurs within the uterus, gastrointestinal tract, and mesentery. Primary skeletal leiomyosarcoma is exceedingly rare. The radiographic appearance is similar to that of other aggressive sarcomas of the bone. Definitive diagnosis is achieved through biopsy or excision and pathologic review.

Leiomyosarcoma of bone: a case report

The aim of this paper is to present clinicopathologic features and immunohistochemical findings of a primary leiomyosarcoma of bone occurring in the proximal femur of a 46-year-old Caucasian male patient. Each case report on this exceedingly rare entity contributes to the notion of this disease.

The ‘other’ bone sarcomas

We aimed to identify the incidence, outcome and prognostic factors associated with spindle cell sarcomas of bone (SCSB). We studied 196 patients with a primary non-metastatic tumour treated with the intent to cure. The results were compared with those of osteosarcoma patients treated at our hospital during the same period. The overall incidence of SCSB was 7.8% of all patients with a primary bone sarcoma. The five- and ten-year survival rates were 67.0% and 60.0%, respectively, which were better than those of patients with osteosarcoma treated over the same period. All histological subtypes had similar outcomes. On univariate analysis, factors that were significantly associated with decreased survival were age > 40 years, size > 8 cm, the presence of a pathological fracture, amputation, involved margins and a poor response to pre-operative chemotherapy. Multivariate analyses showed that age > 65 years, amputation and involved margins were all statistically significant prognostic factors. Involved margins and poor response to pre-operative chemotherapy were associated with an increased risk of local recurrence. SCSB has a better prognosis than osteosarcoma when matched for age. Most prognostic factors for osteosarcoma also seem to apply to SCSB. Patients with SCSB should be treated in the same way as patients of the same age with osteosarcoma.

Primary leiomyosarcoma of bone--a clinicopathologic study of 8 uncommon cases with immunohistochemical analysis and clinical outcomes

Primary leiomyosarcoma of bone is a rare and a diagnostically challenging tumor entity. Over a 7-year period, we identified 8 such cases that fulfilled the diagnostic criteria in 6 men and 2 women, with age ranging from 25 to 59 years (mean, 42.7 years). All cases were noted in the lower limbs, including femur and tibia as the commonly involved bones in 4 and 3 cases, respectively. On radiography, the most consistent feature was a solitary osteolytic lesion with cortical destruction, unassociated with matrix formation. On histopathology, all cases showed spindly sarcomatous cells, mostly arranged in fascicles and whorls. Of 8 cases, 6 (75%) were of high grade. Prominent vasculature was noted in 5 cases. Two cases displayed focal mineralization, including calcification and heterotropic woven bone formation in 1 case each, but lacked malignant osteoid or chondroid matrix. One case showed osteoclast-like giant cells. On immunohistochemistry, smooth muscle actin was diffusely positive in all cases (100%), desmin was positive in 6 (75%) of 8 cases, and h-caldesmon was positive in 5 (83.3%) of 6 cases. Five cases underwent surgery, including 3 amputations and 2 wide excisions. One case underwent chemotherapy. On follow-up, 5 cases developed metastasis, including 1 case with another, who died within 17 and 5 months. Leiomyosarcoma of bone is uncommon and diagnostically challenging. An index of suspicion is necessary for this diagnosis, especially in cases of lytic, destructive bone lesions, unassociated with matrix production, that show spindly sarcomatous cells on histopathology. Immunohistochemical analysis, including an optimum panel formed by smooth muscle actin (diffuse positivity), desmin, and h-caldesmon, is necessary for substantiating this diagnosis. Surgery forms the treatment mainstay. The prognosis appears to be dismal.