Surgical Treatment of Intramuscular Myxoma

Intramuscular myxoma: unusual observation of spontaneous tumor size shrinkage

Soft tissue tumors, whether benign or malignant, may grow over time or remain stable, but they usually do not spontaneously decrease in size. However, there are exceptions, such as inflammatory conditions, desmoid tumors, or benign cysts. Intramuscular myxomas are benign soft tissue tumors that typically present as a solitary, slow-growing, painless mass. They are generally treated by surgical resection, after which recurrence is rare. Here, we present a brief series of three unusual cases of intramuscular myxomas that spontaneously decreased in size. They were located in the cervical region, the right lower extremity, and the paravertebral lumbar region. Imaging findings and percutaneous biopsies confirmed the diagnosis in all cases. Follow-up imaging showed a spontaneous reduction in lesion volume over time, far exceeding the amount of tissue sample removed during biopsy. This unusual observation of spontaneous shrinkage may call into question the subsequent therapeutic approach to these lesions.

The Clinical, Radiological, and Histopathological Characteristics of Intramuscular Myxoma: A Case Report

In this study, we discuss the clinical, radiological, and histopathological characteristics of intramuscular myxomas (IMM), a rare form of benign soft tissue tumors. We report the case of a 47-year-old female patient presenting with a painless, non-inflammatory mass in the right thigh, which was mobile relative to both superficial and deep planes. Imaging, biopsy, and subsequent histopathological study established the diagnosis of intramuscular myxoma. The patient underwent surgical excision of the mass, with a straightforward postoperative course. It is important to distinguish IMM from malignant tumors, such as soft tissue sarcomas, through comprehensive examinations including imaging and biopsy. The recommended treatment is surgery for complete excision of the mass, with an exceptionally low recurrence rate.

Rare forearm intramuscular myxoma: A case report

Key Clinical Message

Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that occurs mainly in skeletal muscles which can be removed through surgery after diagnosis.

Abstract

Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that typically occurs in skeletal muscles. Its diagnosis is based on magnetic resonance imaging (MRI) and histopathologic evaluation of the lesion. In our report, we describe the case of a 60-year-old female with an IMM in the supinator muscle of the right forearm, which was confirmed by MRI and histopathologic examination. Following surgery to remove the mass, a follow-up confirmed the patient's recovery and the absence of movement limitations in the elbow joint.

Diagnostic and Therapeutic Pathways of Intramuscular Myxoma

Intramuscular myxomas (IMMs) are benign tumors. Evidence regarding diagnostic and therapeutic pathways is rare, and guidelines do not exist due to their low incidence. The aim of this study was a retrospective analysis at a university cancer center and the interdisciplinary re-evaluation of the individual diagnostic and therapeutic procedures. Overall, 38 patients were included in the study. IMMs occurred mostly in middle-aged women. At the time of first consultation, 57.9% had few symptoms or were asymptomatic. In 92.1% of the cases, the tumor was localized in the extremities. The lower extremity was affected in 73.7%. The average size of IMMs was 5.0 cm. The proximally located tumors in the gluteus, thighs, and upper arms were significantly larger (p = 0.02) than the distally-located tumors in the forearms and lower legs. An MRI was performed in 97.4%. Based on imaging, an IMM was suspected in 5.6% by radiologists and in 54.1% by musculoskeletal surgeons. An incision biopsy was performed in 68.4% and led in 100.0% to the right histopathological diagnosis. In total, 89.5% of IMMs were resected. Postoperative complications requiring revision occurred in 8.8%. Recurrences or degenerations of IMMs were not reported in any of these cases.

Artificial intelligence significantly improves the diagnostic accuracy of deep myxoid soft tissue lesions in histology

Deep myxoid soft tissue lesions have posed a diagnostic challenge for pathologists due to significant histological overlap and regional heterogeneity, especially when dealing with small biopsies which have profoundly low accuracy. However, accurate diagnosis is important owing to difference in biological behaviors and response to adjuvant therapy, that will guide the extent of surgery and the need for neo-adjuvant therapy. Herein, we trained two convolutional neural network models based on a total of 149,130 images representing diagnoses of extra skeletal myxoid chondrosarcoma, intramuscular myxoma, low-grade fibromyxoid sarcoma, myxofibrosarcoma and myxoid liposarcoma. Both AI models outperformed all the pathologists, with a significant improvement of accuracy up to 97% compared to average pathologists of 69.7% (p < 0.00001), corresponding to 90% reduction in error rate. The area under curve of the best AI model was on average 0.9976. It could assist pathologists in clinical practice for accurate diagnosis of deep soft tissue myxoid lesions, and guide clinicians for precise and optimal treatment for patients.