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

Jun Nishio,Masatoshi Naito

doi:10.1186/1477-7819-10-132

Abstract

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.

Highlights

Intramuscular myxoma is a rare benign soft tissue tumor of unknown origin
To the best of our knowledge, F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings of intramuscular myxoma have been mentioned in one prior publication [2]
Some intramuscular myxomas show focal areas of hypercellularity and hypervascularity, which may be confused with several myxoid soft tissue sarcomas such as myxoid liposarcoma, low-grade myxofibrosarcoma, and low-grade fibromyxoid sarcoma [9]

Summary

Introduction

Intramuscular myxoma is a rare benign soft tissue tumor of unknown origin. It usually occurs as an isolated lesion. Background Intramuscular myxoma is a rare benign soft tissue tumor of unknown origin. We describe a case of intramuscular myxoma with a mild FDG uptake and discuss its clinicopathologic and radiologic features. FDG PET images demonstrated an increased uptake in the left buttock.

Results

Conclusion