MR imaging of muscular sarcoidosis after steroid therapy

Muscular sarcoidosis involving the chest and abdominal walls: case report with MR imaging

Sarcoidosis is an inflammatory disorder that is characterized by the presence of noncaseating granulomas in tissues, involving many organs and tissues. Extra-pulmonary, especially muscular sarcoidosis is a rare condition. The most common location of the muscular sarcoidosis is known to be the proximal muscles of the extremities; however, there have been no cases of diffuse involvement of the chest and abdominal wall muscles. Here, we report a rare muscular sarcoidosis with infiltrative pattern in the chest and abdominal wall muscles and describe the MR imaging findings that were mistaken as lymphoma at initial diagnosis. Although our case did not show characteristic MR findings of muscular sarcoidosis, clinicians or radiologists who are aware of these imaging features can perform early systemic survey for sarcoidosis. Also muscle biopsy is very important to confirm the sarcoidosis and distinguish it from other tumors.

MR Imaging of Atraumatic Muscle Disorders

Atraumatic disorders of skeletal muscles include congenital variants; inherited myopathies; acquired inflammatory, infectious, or ischemic disorders; neoplastic diseases; and conditions leading to muscle atrophy. These have overlapping appearances at magnetic resonance (MR) imaging and are challenging for the radiologist to differentiate. The authors organize muscle disorders into four MR imaging patterns: (a) abnormal anatomy with normal signal intensity, (b) edema/inflammation, (c) mass, and (d) atrophy, highlighting each of their key clinical and imaging findings. Anatomic muscle variants, while common, do not produce signal intensity alterations and therefore are easily overlooked. Muscle edema is the most common pattern but is nonspecific, with a broad differential diagnosis. Autoimmune, paraneoplastic, and drug-induced myositis tend to be symmetric, whereas infection, radiation-induced injury, and myonecrosis are focal asymmetric processes. Architectural distortion in the setting of muscle edema suggests one of these latter processes. Intramuscular masses include primary neoplasms, metastases, and several benign masslike lesions that simulate malignancy. Some lesions, such as lipomas, low-flow vascular malformations, fibromatoses, and subacute hematomas, are distinctive, but many intramuscular masses ultimately require a biopsy for definitive diagnosis. Atrophy is the irreversible end result of any muscle disease of sufficient severity and is the dominant finding in disorders such as the muscular dystrophies, denervation myopathy, and sarcopenia. This imaging-based classification, in correlation with clinical and laboratory data, will aid the radiologist in interpreting MR imaging findings in patients with atraumatic muscle disorders. ^©RSNA, 2018.

Tumour-like muscular sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology with variable manifestations, which may affect virtually any organ. Muscular sarcoidosis is a rare entity, and among this group of muscular lesions, the tumour-like muscular sarcoidosis subtype is extremely rare. We report on two sarcoidosis cases that presented muscular sarcoid lesions with subcutaneous tumours.

Neurosarcoïdose : état des connaissances

The origins of neurosarcoidosis, a multisystemic granulomatous disease, remain unknown. Nervous system localizations remain rare, but severe. Lymphocytic meningitis, psychiatric disorders, diabetes insipidus and cranial nerve palsy are the most frequent signs. Cerebral fluid test and cervical medullar and cerebral MRI with gadolinium have to be performed first. In some cases, histological evidence of granuloma have to be obtained with neuromuscular, meningeal or cerebral biopsies. Functional impairment and life-threatening conditions require early corticosteroid therapy. In worsening cases or in the event of no therapeutic response or poor tolerance to corticosteroids, other immunosuppressive agents should be associated. Maintenance therapy and most often life long maintenance therapy allow a continuous success while avoiding relapse.

Imaging Findings in Three Cases of the Nodular Type of Muscular Sarcoidosis

OBJECTIVE

Sarcoidosis is a granulomatous multisystem disorder that may uncommonly involve muscle. We report the sonographic and MRI findings in three cases of the nodular type of muscular sarcoidosis.

CONCLUSION

Intramuscular hypoechoic well-defined nodules in young patients or patients with a history of sarcoidosis suggest the diagnosis of intramuscular sarcoid. MRI is useful in detecting muscle sarcoid, evaluating the extent and distribution of muscle involvement, and monitoring the patient during follow-up after steroid therapy. MRI showed nodules that were iso- or hyperintense relative to muscle on T1-weighted sequences. On T2-weighted images and STIR sequences, we observed numerous intramuscular nodules of homogeneous high signal intensity. All nodules enhanced homogeneously on contrast-enhanced T1-weighted sequences. Disappearance of all nodules was seen on follow-up sonograms and MR images after patients had received steroid therapy.

Magnetic resonance imaging and nuclear imaging in sarcoidosis

MRI has become of great importance in the study of several aspects of sarcoidosis. The main development has taken place in the assessment of neurosarcoidosis, but MRI may be also useful in the evaluation of sarcoidosis of the bone, muscle, heart, and intrathoracic. Nuclear imaging in sarcoidosis acquired a great expansion with the introduction of (67)gallium scanning as a marker of activity. Although its current use has decreased, it is still very helpful in particular situations of the disease. Other more recently introduced nuclear imaging techniques may have a role in the evaluation of cardiac sarcoidosis and in the assessment of the extension of the disease.

Aspiration biopsy of nodular sarcoidosis of the muscle

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis.