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

Angiofibroma of Soft Tissue on MRI and FDG PET/CT Image

ABSTRACT

Angiofibroma of soft tissue is a rare benign mesenchymal neoplasm. We reported a case of angiofibroma of soft tissue in a 61-year-old woman. MRI examination indicated a soft tissue mass in the right lower thigh, which showed isosignal intensity on T1-weighted imaging and heterogeneous high signal intensity on T2-weighted imaging. This lesion had intense tracer uptake, with an SUVmax of 7.24 on FDG PET/CT. Our case revealed that when soft tissue masses with intense FDG uptake on PET/CT are encountered, angiofibroma of soft tissue should be considered in the differential diagnosis.

Diagnostic value of ultrasonography and other imaging examinations in patients with intramuscular myxoma: A case series and literature review

Intramuscular myxoma (IM) is a rare benign soft tumor of mesenchymal origin. Most IMs are located in the large skeletal muscles, and they are typically painless slow-growing masses that are detected incidentally. Surgical excision of IM usually has a good prognosis. Because of its rarity, diagnosing IM via imaging modalities such as ultrasonography (US), computed tomography, positron emission tomography/computed tomography, and magnetic resonance imaging (MRI) can be challenging. Relevant literature and cases were selected as per the inclusion and exclusion criteria. Characteristic imaging findings include a well-defined, ovoid mass with regular morphology and an orientation whereby the long axis is aligned with the course of muscle fibers. In US, IMs exhibit solid cystic mixed echo without obvious blood flow signal. However, MRI reveals hypointensity on T1-weighted images and hyperintensity on T2-weighted images with mild and patchy enhancement. In cases of suspected or potential IM, US and MRI can provide excellent resolution at a reasonable cost. This report aims to improve the recognition rate of IM. Herein, we review imaging characteristics that can contribute to the differential diagnosis of IM.

Multiple paraspinal intramuscular myxomas: case report

Intramuscular myxomas (IMMs) are rare benign tumors of mesenchymal origin that are most often located in large skeletal muscles, particularly of the thigh. They have also been reported within the paraspinal musculature and should be considered in the differential diagnosis of a paraspinal mass. These lesions can cause neurological symptoms due to mass effect. This is a report of a 52-year-old man with multiple paraspinal tumors that exhibited concerning growth on serial imaging studies. To the authors' knowledge, this represents the first report of a patient with multiple paraspinal myxomas. CT-guided biopsy followed by surgical excision of the largest mass was performed. Histopathological analysis was consistent with an IMM. Patients with multiple IMMs often have an underlying genetic syndrome such as Mazabraud syndrome, McCune-Albright syndrome, or Carney complex. Despite variable growth patterns and associations with genetic syndromes, multiple IMMs have had no documented cases of malignant transformation into myxoid sarcoma; therefore, surgical excision should be considered based on a patient's individual symptoms.

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.

18F-FDG PET/CT and MRI features of myxoid liposarcomas and intramuscular myxomas

OBJECTIVE

To examine the imaging characteristics of intramuscular myxomas (IM) and myxoid liposarcomas (MLS) on ¹⁸F-FDG PET/CT and MRI.

MATERIALS AND METHODS

With IRB approval, our institutional imaging database was searched for pathologically proven IM and MLS evaluated by ¹⁸F-FDG PET/CT and MRI. PET/CT and MRI imaging characteristics were recorded and correlated with pathologic diagnosis.

RESULTS

We found eight patients (2 M, 6 F) with IM (mean age 65.6 ± 10.4 years) and 16 patients (7 F, 9 M) with MLS (mean age 42.8 ± 16.3 years). MRI was available in 7/8 IM and 15/16 MLS patients. There was no significant difference between the two groups in SUVmax (IM 2.7 ± 0.8, MLS 3.0 ± 1.0; p = 0.35), SUVmean (1.7 ± 0.4, 1.5 ± 0.5; p = 0.40), total lesion glycolysis (101.8 ± 127.3, 2420.2 ± 4003.3 cm³*g/ml; p = 0.12), metabolic tumor volume (62.3 ± 71.1, 1742.9 ± 3308.0 cm³; p = 0.17) or CT attenuation (p = 0.70). MLS occurred in younger patients (p = 0.0015), were larger (16.4 ± 8.2 vs. 5.6 ± 2.5 cm; p = 0.0015), more often T1 hyperintense (p = 0.03), with nodular enhancement (p = 0.006), and macroscopic fat on CT (p = 0.0013) and MRI (p = < 0.001) compared to myxomas.

CONCLUSIONS

IM and MLS most commonly demonstrate low-grade FDG activity and overlapping metabolic measures on PET/CT. MRI is useful in differentiation, but MLS can present without macroscopic fat on MRI, underscoring the importance of radiologic-pathologic correlation for accurate diagnosis.

Mazabraud's Syndrome Mimicking Metastases on FDG PET/CT in a Patient With Colon Cancer

Mazabraud's, a syndrome consisting of fibrous dysplasia and soft tissue myxomas, is a rare disorder with less than 100 cases reported in the literature. Appearance of lesions in Mazabraud's syndrome on FDG PET/CT scan in an oncological scenario can be misinterpreted as malignancy. We present the case of a 69-year-old woman, diagnosed with metastatic colon carcinoma and suspected osseous as well as soft tissue metastases, who was later found to have concomitant Mazabraud's syndrome. This case describes the diagnostic dilemma associated with this unusual entity and importance of differentiating benign and malignant etiologies on FDG PET/CT scan.

Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography in evaluation of residual intramuscular myxoma

Intramuscular myxoma (IM) is a rare benign neoplasm. In a patient diagnosed with IM of left thigh, we report the utility of a postoperative fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography scan in assessing the efficacy of surgical excision.

Intramuscular myxoma in the chest wall

Intramuscular myxomas are benign soft-tissue tumors that often develop in the thigh. A 66-year-old woman was referred with an abnormal shadow on chest roentgenogram. The tumor was well defined and smooth and originated from the second intercostal space. Positron emission tomography showed no accumulation of 18F-fluorodeoxyglucose in the tumor. The patient attended the outpatient department for follow-up care. Because the mass grew slightly after 52 months, the patient underwent complete removal by video-assisted thoracoscopic surgery. On histopathological examination, the tumor was diagnosed as an intramuscular myxoma in the chest wall. The patient has had no recurrence 3 years after surgery. A case of intramuscular myxoma in the chest wall, completely resected by video-assisted thoracoscopic surgery, is reported. A well-defined, smooth, homogeneous mass in the chest wall may therefore be intramuscular myxoma.

FDG PET/CT and MR imaging of intramuscular myxoma in the gluteus maximus

Intramuscular myxoma is a rare benign soft tissue tumor which may be mistaken for other benign and low-grade malignant myxoid neoplasms. We present the case of a 63-year-old woman with an asymptomatic intramuscular myxoma discovered incidentally on a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography. PET images showed a mild FDG uptake (maximum standardized uptake value, 1.78) in the left gluteus maximus. Subsequent magnetic resonance (MR) imaging revealed a well-defined ovoid mass with homogenous low signal intensity on T1-weighted sequences and markedly high signal intensity on T2-weighted sequences. Contrast-enhanced MR images showed heterogeneous enhancement throughout the mass. The diagnosis of intramuscular myxoma was confirmed on histopathology after surgical excision of the tumor. The patient had no local recurrence at one year follow-up. Our case suggests that intramuscular myxoma should be considered in the differential diagnosis of an oval-shaped intramuscular soft tissue mass with a mild FDG uptake.