Mazabraud’s syndrome: Intramuscular myxoma associated with fibrous dysplasia

Intramuscular myxoma of the thigh: A case report

Intramuscular Myxomas are rare benign soft tissue tumors which usually occur between the ages 40 and 70 years and are more common among females. A thorough history and examination can help with diagnosis and it can be confirmed via histological examination. A 40-year-old female presented with a swelling in the medial aspect of right thigh which measured about 5 × 5 cm. Ultrasound, magnetic resonance imaging, and histopathology examination confirmed the diagnosis and a complete surgical resection was performed to remove the mass. Intramuscular myxoma should be included in differential diagnosis of sarcomas, hemangioma, desmoid tumor, clear cell sarcoma, and lipomas. Magnetic resonance imaging should be the investigation of choice, and histopathology remains the gold standard of investigation. Complete surgical excision with negative margins is the treatment of choice.

A case of intramuscular lumbar myxoma: Uncertainty in the preoperative diagnosis of a spinal soft tissue tumour

We report an uncommon case of a 76-year-old woman who presented with lower back pain, an intermittent L5 radiculopathy and a right palpable paraspinal mass. Imaging studies revealed a 7-cm lumbar paraspinal pseudo-cystic soft tissue tumour developed in the paravertebral musculature, without a clear radiological diagnosis. Gross total surgical resection was performed, resulting in complete resolution of pain. Histopathological studies revealed an intramuscular (IM) myxoma. With a low positive predictive value of radiological work-up and a poor yield of percutaneous biopsies, surgery remains the mainstay treatment for these rare soft tissue tumours of the lumbar spine. Intramuscular myxomas show excellent postoperative results.

Mazabraud's Syndrome - A Diagnosis Commonly Missed

Introduction:

Mazabraud’s syndrome is a rare benign disorder characterized by the association of single or multiple intramuscular myxomas with monostotic or polyostotic form of fibrous dysplasia. Around 80 cases have been described till date; however, a higher incidence may be expected due to silent nature of the disease and missed diagnosis. The authors report one such case of a missed diagnosis.

Case Report:

A 39-year-old lady presented with recurrent soft tissue myxomas in thigh. A thorough evaluation with radiographs and magnetic resonance imaging (MRI) and a clinical suspicion of this rare entity helped in making the diagnosis of Mazabraud’s syndrome. The patient was treated with wide excision of the recurrent thigh swelling and watchful observation of two other asymptomatic swelling detected on MRI examination. Bisphosphonate therapy was given for fibrous dysplasia. At latest follow-up after 2 years, the patient was asymptomatic with no recurrence.

Conclusion:

The report highlights the importance of a high degree of suspicion of this clinical entity in patients treated for recurrent soft tissue swelling as both myxomas and fibrous dysplasia behave differently than their isolated counterparts.

A case of a myxoma within the obturator externus muscle

Intramuscular myxomas (IM) are rare benign tumors of mesenchymal origin. These tumors have a high myxoid content and a nonspecific radiologic appearance. Here we describe the case of a patient with an IM in an infrequent location; within the obturator externus muscle. A singular approach was utilized for the resection of this tumor in such rare location.

Despite IM being benign tumors, patients may require a surgical excision due to the difficulty of differentiating these tumors, with unreliable imaging features, from other myxoid soft tissue masses.

Prevalence and Clinical Features of Mazabraud Syndrome: A Multicenter European Study

BACKGROUND

Mazabraud syndrome is a rare disorder, characterized by the presence of fibrous dysplasia (FD) with associated intramuscular myxomas. Data are scarce on the prevalence, clinical features, and natural history of this disorder and outcomes. In this multicenter study, we evaluated a series of patients from 6 European centers.

METHODS

All centers affiliated with the European Musculo-Skeletal Oncology Society (EMSOS) were invited to include data on all patients with Mazabraud syndrome who were seen between 1980 and 2015. The study investigated the prevalence of Mazabraud syndrome, the type, severity, and localization of FD lesions in relation to myxomas, the histopathology of myxomas, and results of GNAS-mutation analysis, when available.

RESULTS

Thirty-two patients (22 female) from 6 centers were included. The prevalence of Mazabraud syndrome was 2.2% in the combined cohort of 1,446 patients with FD, and the syndrome was diagnosed at a mean of 10.1 years after diagnosis of FD. The myxomas were predominantly localized in the upper leg. Excision was performed in 20 patients, recurrence occurred in 6 of these patients (30%) at a median of 8.5 years (range, 1.9 to 16.0 years), and revision surgery was necessary in 5 (25%). High cellularity of myxomas was associated with recurrence (p < 0.05). A GNAS mutation was identified in the myxoma tissue of 5 (83%) of 6 patients with GNAS-mutation analysis.

CONCLUSIONS

This study is the first, to our knowledge, to provide data on the prevalence of Mazabraud syndrome in a relatively large cohort. Although the outcomes of surgical resection were good, a quarter of the patients required revision surgery despite clear resection margins. High cellularity of myxomas was associated with recurrence. GNAS mutations were identified in 83% (5 of 6), emphasizing the shared origin of FD and myxomas. Our data show that patients with FD who have disproportionate complaints, irrespective of FD type, extent, or severity, should be investigated for the possible presence of myxomas.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Isolated intraosseous extra-gnathic orbital myxoma: a clinicopathologic case report

A 19-year-old female student presented with painless, progressive proptosis in the right eye for the past six months causing significant cosmetic blemish and double vision. Clinical evaluation revealed normal visual acuity, normal pupillary reflex, severe proptosis, and dystopia. Orbital imaging revealed a heterogeneous mass in superior orbit displacing the globe inferiorly and causing extensive bony erosion of frontal bone superiorly and invading the frontal sinus. Excision biopsy was performed with en-bloc removal of the tumor. Surgical delivery of a slimy mass with infiltrated bony tissue led to a presumptive diagnosis of myxoid liposarcoma. Careful histopathologic analysis coupled with immunohistochemical studies were performed which established the rare diagnosis of low-grade myxoid spindle cell neoplasm with features suggestive of intraosseous myxoma. On follow-up at 15 months, our patient revealed no signs of recurrence. Isolated intraosseous orbital myxoma is a rare entity; only two such cases have been reported in the literature.

Intramuscular Myxoma in the Supinator Muscle with Transient Postoperative Posterior Interosseous Nerve Palsy: A Case Report

Background:

Intramuscular myxomas are rare, benign mesenchymal tumors in the musculoskeletal system, and usually, the tumors arise in the large muscles of the thigh, buttocks, shoulder, and upper arm. However, a tumor of the forearm is very rare. Herein, we describe the case of an intramuscular myxoma in the supinator muscle of a 56-year-old female patient.

Case Presentation:

Magnetic resonance imaging showed a well-defined mass that was hypointense with the peritumoral fat ring sign. The differential diagnoses might have been myxoma, schwannoma, or intramuscular hemangioma. The histopathological image showed abundant myxoid tissue, hypocellularity, and poor vascularization. The cells of the tumor were spindle and stellate-shaped with normochromic nuclei. Based on these findings, the pathological diagnosis was an intramuscular myxoma. After excising the tumor, the patient had transient posterior interosseous nerve palsy.

Conclusion:

This tumor is curative by resection in toto; however, when the tumor exists in the forearm, surgeons should be careful to avoid damaging surrounding tissues because the tumor is very hard and relatively large compared to the forearm.

Monosotic fibrous dysplasia and solitary intramuscular myxoma of the head and neck: A unique presentation of Mazabraud's syndrome and a literature review

Mazabraud's syndrome (MS) is a rare disease that is a combination of fibrous dysplasia and intramuscular myxomas. MS is a benign lesion and there is little data on the disease due to its low incidence. In the present study, the case of a 38-year-old patient who presented with a soft-tissue mass involving the masseter and swelling at the mandibular body and mandibular ramus is reported. Since the mandible is an important aesthetic and functional organ in the oral and maxillofacial region, surgery was primarily aimed at resecting the tumor, with good safety margins, and reconstructing the resultant defect. The lesions were pathologically diagnosed as MS. The unique features of this case included the painless and monostotic fibrous dysplasia, the solitary intramuscular myxomas involving the jaw and the male gender of the patient. MS usually occurs in the lower extremities, with an unusual predilection for the right limb; however, it rarely occurs in the head and neck region. A retrospective analysis of the clinical features and management of MS was also performed in the present study, together with a literature review. From the literature, it was concluded that the incidence of MS is ~2.3-fold greater in female patients than in male patients, and that the age of onset of MS ranges between 17 and 82 years, with an average age of 46.25 years.

Mazabraud's syndrome: Report of its first incidence in the Middle East and a literature review

INTRODUCTION

Mazabraud's syndrome, a rare benign disease with indolent course, is best described as an association between soft tissue myxoma and fibrous dysplasia of the bones. In this report, we describe the first case of this syndrome from Saudi Arabia.

CASE PRESENTATION

A 24-year-old male in overall good health status, presented with progressive left knee swelling over 6 years with no other associated symptoms. The swelling measured 5 cm in diameter, with smooth surface, and soft palpable texture. Radiological examination followed by histopathological examination of the excised mass confirmed our diagnosis of Mazabraud's syndrome. The patient was closely followed up with systematic examination with no recurrence.

DISCUSSION

Fibrous dysplasia, soft tissue myxoma and multiple endocrinological diseases like McCune-Albright syndrome characterize Mazabraud's syndrome. Furthermore, fibrous dysplasia is found to be associated with GNA1S gene mutation. Many patients can have asymptomatic course of the disease but may present with pathological fractures, pain, and limitation of movement when the myxoma is near the joints or just simple cosmetically disturbing swelling like in our case.

CONCLUSION

Patients with such presentation need to be investigated thoroughly to rule out associated diseases and to evaluate the extent of such pathology. The improvement of radiological modalities can help in narrowing the differential diagnosis and following the patient to early detect the recurrence or any malignant transformation of the condition.

Intramuscular myxoma of the paraspinal muscles: A case report and systematic review of the literature

Intramuscular myxoma (IM) is a rare mesenchymal tumor of the head and neck region. The current study reports a case of a 45-year-old man who presented with a painless neck mass. Imaging showed involvement of the levator scapulae and scalene muscles. Core needle biopsy was consistent with intramuscular myxoma. Surgical excision was performed and follow-up for 30 months showed no recurrence. The present study includes a systematic review of head and neck IMs, with a summary of the clinical and demographic parameters of all reported cases in the head and neck region. Surgery was curative in 28 of the 29 published cases, as well as in the current case (96.7%), with the lone recurrent tumor cured following re-resection. Females constituted 57% of the cases and the mean age was 49.7±20.4 years. Although uncommon, IM should be considered in the differential diagnosis of deep neck masses, and surgical excision is the treatment of choice with a low risk of recurrence.

Radiological characteristics and management of intramuscular myxoma of the temporal muscle: case report

The patient was a 51-year-old male with a 3-year history of a slow-growing, asymptomatic, subcutaneous mass in the left temporal region. Magnetic resonance imaging revealed a well-defined extracranial lesion with heterogeneous enhancement and without invasion of the skull. A variety of soft tissue tumors were included in the differential diagnosis. The patient underwent total resection of the tumor, and a diagnosis of intramuscular myxoma was confirmed histologically. There was no evidence of recurrence at 6-month follow-up. The present case is the first characterization of the radiological appearance of intramuscular myxoma in the temporal muscle. I emphasize that increased awareness of this rare lesion and a careful clinical and radiological preoperative assessment are crucial in determining an appropriate treatment strategy for patients with a soft tissue tumor of the head.

Intramuscular Myxoma

Intramuscular myxoma is an uncommon benign soft tissue tumor that may arise from fibroblasts that produce an excessive amount of mucopolysacchrides. It is typically seen in adults in the large muscles of extremities and exhibits typical radiological features on sonography and magnetic resonance imaging. A case of intramuscular myxoma in the left Vastus intermedius is described in a 52-year-old man who presented with gradually increasing swelling in the thigh. The case illustrates characteristic radiologic “bright cap and rim” signs with pathologic correlation.

Mazabraud syndrome

A 25 year old lady presented with pain and swelling of left thigh. On examination she was found to have tenderness of left femur with a separate soft tissue swelling within the thigh muscle. Further evaluation revealed expansile bony lesion on X-ray of left tibia and multiple hot spots on bone scan suggestive of fibrous dysplasia. The soft tissue swelling on excision and histopathological examination was found to be intramuscular myxoma. The combination of the above two, called Mazabraud syndrome is being reported.

Diagnostic value of investigating GNAS mutations in fibro-osseous lesions: a retrospective study of 91 cases of fibrous dysplasia and 40 other fibro-osseous lesions

GNAS (guanine nucleotide-binding protein/α-subunit) mutations that induce the activation of G-protein α-subunit participate in the pathogenesis of fibrous dysplasia. The aim of this study was to evaluate the sensitivity and specificity of GNAS mutations in fibrous dysplasia and other fibro-osseous lesions, to assess the value of investigating this mutation in the diagnosis of fibro-osseous lesions. We studied 91 cases of fibrous dysplasia. The quality and/or quantity of genomic DNA were suitable for molecular analysis for 51 cases of fibrous dysplasia. GNAS mutations were investigated by three techniques: high-resolution melting (exon 8), allele-specific PCR (exons 8 and 9) and/or direct DNA sequencing (exons 8 and 9). Fibrous dysplasia samples were classified blind to the GNAS mutation status into six histological subtypes as conventional, fibro-involutive, osteosclerosing, cementifying, osteocartilaginous and with prominent aneurysmal cystic changes. We also studied 14 cases of low-grade osteosarcoma, 21 cases of ossifying fibroma, 3 cases of osteofibrous dysplasia, 1 case of osseous dysplasia of the jawbone and 1 post-traumatic lesion of the ribs. Twenty-three cases of fibrous dysplasia (45%) showed mutations of codon 201 (exon 8, p.R201H or p.R201C). No mutation was found on codon 227 (exon 9). GNAS mutations in conventional fibrous dysplasia were detected in the same proportion (47%) as in the other histological subtypes (47%, P=0.96), regardless of sex (P=0.44), age (P=0.90) and location (P=1). GNAS mutations were not detected in any other fibro-osseous lesions. The GNAS mutation was thus specific to fibrous dysplasia in the context of fibro-osseous lesions. The particular mosaicism of mutant and non-mutant cells within the lesion or the existence of other mutations not already described could explain the lack of GNAS mutation in cases of fibrous dysplasia. Investigating this mutation may constitute a valuable complementary diagnostic tool, despite its low sensitivity, particularly in unconventional morphologically different subtypes of fibrous dysplasia.

Mazabraud's syndrome: case report and literature review

Mazabraud's syndrome is a rare disorder characterized by the association of single or multiple intramuscular myxomas with fibrous dysplasia. Here, we present the first case of Mazabraud's syndrome visualized on 18F-FDG PET/CT with histopathological confirmation of the myxoma. Our case demonstrates a slightly increased FDG uptake (SUVmax 2.1) within the myxomas and a moderately to highly increased tracer uptake (SUVmax 7.0) within the fibrous dysplastic lesions. The typical histological appearance of the intramuscular myxoma confirmed the radiological diagnosis. Further, we discuss the imaging findings and the histopathological features of this rare case with a review of the related literature.

Giant paravertebral myxoma

The study design includes case report and clinical discussion. The objective was to describe a rare case of a giant intramuscular myxoma (IMM) presenting as a mass in the paravertebral muscles. Myxoma is a rare benign soft tissue tumour of mesenchymal origin. Although intramuscular presentation is common, they are rare in the paravertebral muscles and are characteristically <5 cm in length. We report the clinical and imaging features in a 70-year-old woman presenting with back pain, asymmetry of the waist and a mass in right paravertebral region. This was originally misdiagnosed as a juxtafacet synovial cyst after CT-guided biopsy. The mass was excised en bloc and sent for histology. This revealed a low-grade myxoid neoplasm with features of an IMM. The patient went on to make a complete recovery. To our knowledge, this is only the fifth case of paravertebral IMM reported in the literature and at approximately 15 cm in length may be the largest encountered in clinical practice.

F-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging in left thigh intramuscular myxoma

We report F-18 FDG PET-CT appearance of biopsy-proven intramuscular myxoma (IM) in a 69-year-old woman who presented with a left thigh mass. The tumor appears as a well-defined, hypodense mass with thin septation on CT images and mild uptake on PET images. IMs are rare benign myxoid tumors characterized by a paucity of cells, diminished vascularity, and minimal mitotic figures. They most often present as slow-growing, painless, deep-seated intramuscular masses. The mainstay of treatment is surgical resection.

The appearance of Mazabraud's syndrome on 18F-FDG PET/CT

Mazabraud's syndrome is a rare disorder, the main characteristics of which are fibrous dysplasia of bone associated with intramuscular myxomas. The metabolic characteristics of intramuscular myxomas, associated with fibrous dysplasia, have not previously been described with 18F-FDG-PET. Our case demonstrates that there is low, but not insignificant uptake associated with these intramuscular myxomas, with a standardized uptake value (SUV) range between 1.3 and 2.6. As such, this entity merits consideration when evaluating hypoattenuating intramuscular masses, particularly in the context of fibrous dysplasia.

Not all pain in the left iliac fossa is diverticular disease: A case study of a psoas myxoma and review

Intramuscular myxomas are rare, benign, mesenchymal tumours that may present to a wide variety of specialties. We present a case study of an intramuscular myxoma in the psoas muscle, followed by a review of the literature regarding the diagnosis and treatment of intramuscular myxomas