J Korean Soc Radiol.  2013 Jun;68(6):453-457. 10.3348/jksr.2013.68.6.453.

CT, Magnetic Resonance, and 18F-Fluorodeoxyglucose Positron Emission Tomography/CT Imaging Features of Mucosa-Associated Lymphoid Tissue Lymphoma Involving Medial Rectus Muscle: A Case Report

• Lee SK
• Choe MS

• KMID: 2002895
• DOI: http://doi.org/10.3348/jksr.2013.68.6.453

Abstract

We report a case of mucosa-associated lymphoid tissue (MALT) lymphoma involving the medial rectus muscle in a 47-year-old man along with CT, MRI, 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT), and pathologic features. The lesion was manifested as a fusiform enlargement isolated to the right medial rectus muscle with involvement of its tendinous insertion. The lesion was isoattenuating to the brain on non-enhanced CT images, showing as isointense to gray matter on fast spin echo T1- and T2-weighted images with fat saturation, and showed homogeneous enhancement on contrast-enhanced CT and MR images. The maximum standardized uptake value on 18F-FDG PET/CT was 4.9 g/mL. The results of histological and immunohistochemical examinations of the specimen obtained by biopsy of the right medial rectus muscle were consistent with MALT lymphoma. It should be noted that the extraocular muscle (EOM) is a rare location for the involvement of MALT lymphoma, and MALT lymphoma of the EOM may mimic thyroid orbitopathy.

MeSH Terms

Biopsy
Brain
Electrons
Eye Diseases
Fluorodeoxyglucose F18
Hydrazines
Lymphoid Tissue
Lymphoma
Lymphoma, B-Cell, Marginal Zone
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Magnetics
Magnets
Muscles
Positron-Emission Tomography and Computed Tomography
Thyroid Gland
Tomography, X-Ray Computed
Fluorodeoxyglucose F18
Hydrazines

Figure

• 

  Fig. 1 CT, MRI, 18F-FDG PET/CT, and pathologic features of MALT lymphoma involving the medial rectus muscle in a 47-year-old man. A. A non-enhanced CT image shows fusiform enlargement isolated to the right medial rectus muscle (arrows), which is isoattenuating compared with brain. B. A contrast-enhanced CT image reveals homogeneous, moderate enhancement of the enlarged muscle (arrows) with involvement of its tendinous insertion (arrowhead). C, D. Fast spin echo T1- (C) and T2-weighted MR images (D) with fat saturation show fusiform enlargement of the right medial rectus muscle (arrows), which is isointense to the gray matter. E. A gadolinium-enhanced T1-weighted MR image with fat saturation demonstrates homogeneous intense enhancement of the enlarged muscle (arrows) with involvement of its tendinous insertion (arrowhead). F. A 18F-FDG PET/CT image reveals moderate FDG uptake (SUVmax = 4.9 g/mL) within the enlarged right medial rectus muscle (arrow). G. A photomicrograph of histological examination of the specimen obtained by biopsy of the right medial rectus muscle demonstrates diffuse infiltration of relatively small monomorphic atypical lymphoid cells which infiltrate into the skeletal muscle (arrows) (H&E stain, × 400). H. A photomicrograph of immunohistochemical staining demonstrates diffuse strong positivity for CD20 (original magnification, × 400). I. A follow-up gadolinium-enhanced MR image 230 days after initial MR study reveals near complete resolution of MALT lymphoma of the right medial rectus muscle (arrow). Note.-MALT = mucosa-associated lymphoid tissue, SUVmax = maximum standardized uptake value, 18F-FDG PET = 18F-fluorodeoxyglucose positron emission tomography

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