Rice Body Formation Due to Different Etiologies in the Distal Forearm

Summary

The protocol describes the treatment of four rare cases of distal forearm synovitis with rice body formation from diverse etiologies (rheumatoid arthritis, trauma, and idiopathic) that were diagnosed by MRI and treated with surgical synovectomy and nerve release. No recurrence occurred postoperatively, underscoring surgery's efficacy in symptom resolution and prevention.

Abstract

Rice body formation in the distal forearm is an exceedingly rare clinical entity, often associated with chronic synovitis of varying etiologies. This study investigates four unique cases of forearm synovitis with rice body formation, hypothesizing that diverse underlying causes-rheumatoid arthritis, trauma, and idiopathic inflammation-contribute to this condition, and that surgical intervention ensures symptom resolution and prevents recurrence. The patients (three males, one female; aged 42-76 years) presented with heterogeneous clinical manifestations, including localized swelling, nerve compression symptoms, and restricted joint mobility. Diagnostic MRI revealed characteristic features: T1-weighted isointense masses with T2-weighted high-signal foci containing punctate low signals, aiding differentiation from other synovial pathologies. All patients underwent radical synovectomy with median nerve decompression, followed by histopathological analysis. Results demonstrated chronic granulomatous synovitis without evidence of infection (negative cultures and stains for tuberculosis, fungi, and bacteria). Postoperatively, all patients achieved complete symptom relief, with no recurrence or functional deficits observed during follow-up (9-22 months). Literature review highlighted the rarity of forearm rice bodies and underscored MRI's diagnostic superiority over radiography. The cases underscore that rice body formation, while historically linked to rheumatoid arthritis or tuberculosis, can arise from nonspecific synovial inflammation or trauma. Surgical excision combined with nerve release emerged as the definitive treatment, addressing both mechanical compression and inflammatory burden. This study emphasizes the importance of considering diverse etiologies in forearm synovitis, advocating for early MRI evaluation and tailored surgical management to optimize outcomes. The findings contribute to understanding the multifactorial pathogenesis of rice bodies and reinforce the efficacy of synovectomy in preventing recurrence and restoring function.

Introduction

Rice body is a kind of free particle with cartilaginous sheen, similar to the polished white rice, and was first reported by Reise in 1895 in a case of tuberculosis¹. It is mostly associated with rheumatoid diseases and tuberculosis^2,3, but it can also occur in trauma^4,5 or even in the absence of any clear cause^6,7. However, it is still very rare in the clinical practice of hand surgeons. Chronic nonspecific inflammation is thought to be associated with their formation, ....

Protocol

The study protocols were approved by the Medical Ethics Committee of the First Affiliated Hospital of the College of Medicine, Zhejiang University. Written informed consent was obtained from the patients for publication of clinical details and clinical images.

1. Patient evaluation and initial assessment

1. Subject patients presenting with localized forearm swelling, numbness, restricted joint mobility, or positive Tinel's sign to a comprehensive clinical examination. Document symptoms suggestive of nerve compression or synovial pathology (e.g., progressive mass enlargement).
2. Obtain a detailed medical history, includi....

Results

Four cases were treated using the method described above. The details of all the cases and the outcome are described here.

Case 1

A 54-year-old woman presented to the hospital due to a 1-year history of a progressively enlarged mass in the distal left forearm. This mass was associated with numbness at the tip of the left fingers, but there were no sign.......

Discussion

Rice bodies are generally considered to be fibrin complexes resulting from inflammatory processes in the joint, and usually present as progressively enlarged masses⁶. Several hypotheses have speculated on its formation, but there is no consensus on its etiology.

The earliest one was the synovial origin hypothesis. Cheung et al. postulated that rice bodies were triggered by the microinfarcts of synovial cells that resulted from inflammation and ischemia. Subsequently, in.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3.0T MRI Scanner (Skyra)	Siemens Healthineers	Not specified
Acid-fast Stain Kit	Solarbio Life Sciences	G1170-50
bipolar electrotome	Wuhan Maolang Medical Technology Co., Ltd.	20162012293
Cefazolin (Injection, 2g)	Shijiazhuang No. 4 Pharmaceutical Co., Ltd.	H20054256
Grocott Methenamine Silver Stain Kit	Sigma-Aldrich	HT100A
Hematoxylin and Eosin Staining Kit	Beyotime Biotechnology	C0105S
Mayer’s Hematoxylin Stain Kit	Solarbio Life Sciences	G1120
PAS Stain Kit	Solarbio Life Sciences	G1281
Sodium Hyaluronate Gel (2ml)	Seikagaku Corporation Takahagi Plant	H20140533