Atypical proliferative myositis: original MR description with pathologic correlation: case report.

Area of Science:

• Musculoskeletal imaging
• Soft tissue pathology
• Differential diagnosis in oncology

Background:

• Proliferative myositis (PM), proliferative fasciitis, and nodular fasciitis are myofibroblastic proliferations with similar histology.
• Magnetic resonance imaging (MRI) of PM often resembles inflammatory myopathies.
• Distinguishing these entities pre-operatively can be challenging.

Purpose of the Study:

• To report a unique case of proliferative myositis (PM).
• To describe unusual MRI findings in PM that mimic reactive fasciitis.
• To discuss the diagnostic challenges in differentiating PM from other pseudosarcomatous lesions.

Main Methods:

• Case report of a patient with proliferative myositis.
• Review of magnetic resonance imaging (MRI) findings.
• Histopathologic analysis of the lesion.

Main Results:

• The patient's MRI displayed features atypical for PM, suggesting reactive fasciitis.
• Histopathology confirmed proliferative myositis.
• The case demonstrates overlapping imaging and histologic features.

Conclusions:

• Proliferative myositis can exhibit diverse imaging characteristics.
• Unusual MRI findings in PM may mimic other soft tissue lesions like reactive fasciitis.
• Integrated clinicoradiologic and histopathologic assessment is crucial for accurate diagnosis.