Inflammatory focal myositis of the sternomastoid muscle: is there an absolute indication for biopsy? A case report and review of the literature

Rare forms of inflammatory myopathies - part II, localized forms

INTRODUCTION

The idiopathic inflammatory myopathies traditionally comprise dermatomyositis, polymyositis, the anti-synthetase syndromes, immune-mediated necrotizing myopathy and inclusion body myositis. However, there are uncommon localized forms that are less known. In this review, we aimed to cover these uncommon forms.

AREAS COVERED

We identified rare forms of localized myositis on the basis of list provided by the homepage of the Neuromuscular disease center of Washington University, USA and on the basis of the authors' knowledge. We searched PubMed® for relevant articles on these forms with the aim of providing as much as possible information on their clinical manifestations as well as guidance on their work-up and treatment.

EXPERT OPINION

herein, we provide un updated description of rare forms of localized myositis. These forms are often difficult to diagnose because of their localized nature and are sometimes misdiagnosed as tumors. Knowledge about these rare forms of localized myositis can aid in their recognition and treatment.

Recurrent Focal Myositis in Childhood: A Case Report and Systematic Review of the Literature

BACKGROUND

Recurrent focal myositis in adulthood has been documented in case reports and case series. Existing textbooks and reviews do not mention or mention only in passing this entity in childhood. We present a patient with recurrent focal myositis and summarize available clinical, laboratory, management, and outcome data on this entity in the pediatric ages.

METHOD

We describe a nine-year-old patient with recurrent myositis of the left biceps. The terms "myositis" and "relapsing" or "recurrent" or "recurrence" were searched using the United States National Library of Medicine and the Excerpta Medica Database. Pertinent secondary references were also screened.

RESULTS

Another seven pediatric patients (five males and two females, median age ten years, interquartile range 7-14 years) with recurrent focal myositis were identified. In children, the calf was the most frequently involved muscle. Unlike adults, the myositis in children was usually painful. Episodes could be associated with normal or elevated erythrocyte sedimentation rate and blood levels of C-reactive protein, creatine kinase, and aspartate aminotransferase. Abnormalities of the creatine kinase value did not seem to be associated with a higher risk of recurrences.

CONCLUSIONS

Focal myositis has a favorable outcome in children. Recurrent focal myositis is rare and usually benign in childhood. More data are needed to improve the understanding of this condition.

Focal Inflammatory Myositis on 18F-FDG PET/CT

Focal myositis is a rare benign inflammatory pseudotumor that can mimic malignancy, clinically and on imaging. A 34-year-old man presented with a 3-week history of sudden-onset, nontender, left upper neck mass that was nonresolving with antibiotics. Anatomical imaging was concerning for a sarcoma of the sternocleidomastoid muscle with possible regional nodal metastases and surrounding inflammatory change. F-FDG PET/CT showed marked FDG uptake extending around the anterior border of the sternocleidomastoid muscle with no FDG-avid local nodal disease. Core biopsy of the sternocleidomastoid muscle and adjacent node revealed inflammatory changes. A diagnosis of focal inflammatory myositis was made.

[Rapid progressive focal myositis of the head and neck region: a case report]

A 46-year-old woman noticed a painful lump in the neck following fluctuating multiple arthralgia in the previous 3 months. The neck nodule grew rapidly, and was associated with an elevation of the serum creatine kinase activity. Under a diagnosis of focal myositis, corticosteroids were introduced, soon resulting in an amelioration of the symptoms. A biopsy from the neck nodule revealed a muscle tissue with scattered foci of densely packed inflammatory cells. Some of the cells had features similar to the granuloma, which were compact collection of cells and partial tendency of the cell fusion. These findings suggest a close relation between some cases focal myositis and granulomatous myopathy.