Focal Myositis Localised in Gastrocnemius Muscle: is it Different from Isolated Gastrocnemius Myositis? A Case Report.

Son Is,Yoo Sj,Hyun Cl,Kang Ms,Kim Js

doi:10.5704/moj.2111.022

Abstract

Focal myositis is a rare disease defined by an isolated inflammatory pseudotumour usually restricted to one skeletal muscle. Approximately, 250 cases of focal myositis have been described in the literature, and two recent large cohorts have been used to help in the diagnosis. Isolated gastrocnemius myositis, a rare immune-mediated condition, is a diagnostic entity used by internal medicine clinician in the gastrocnemius myalgia syndrome associated with Crohn’s disease (CD). However, focal myositis and isolated gastrocnemius myositis with Crohn's disease share clinical, haematological, pathological, and radiological similarities. We present a case of unilateral focal myositis of the gastrocnemius muscle in a patient with no underlying diseases, including Crohn’s disease. At clinical evaluation, we encountered a challenge in differentiating between focal myositis and the isolated gastrocnemius myositis of Crohn’s due to similarities in clinical manifestation. We attempt to clarify focal myositis and isolated gastrocnemius myositis through our case report and a review of literature.

Highlights

Focal myositis (FM) is characterised by a monofocal mass usually restricted to one skeletal muscle compartment, and was first described in 1977
FM is a rare soft tissue pseudotumour localised in a single musculoskeletal compartment, most commonly involving in adductor muscle and lateralis vastus in lower legs without specific systemic manifestations
Among many autoimmune causes in FM such as Behcet disease, SLE, and systemic sclerosis, there have been no reports associated with CD2,3

Summary

Introduction

Focal myositis (FM) is characterised by a monofocal mass usually restricted to one skeletal muscle compartment, and was first described in 1977. We describe a case of unilateral FM occurring in the gastrocnemius muscle in a 48-year-old female with no other underlying disease, together with a review of the literature. A 49-year-old female patient with no underlying diseases visited the outpatient clinic with a chief complaint of pain around the left calf without a history of trauma, for the duration of one week.

Results

Conclusion