Rice Body Formation Within a Peri-Articular Shoulder Mass.

Anthony Caram,Michele N Edison,Miguel Flores,Kurt Scherer

doi:10.7759/cureus.718

Abstract

Most commonly associated with chronic inflammatory conditions, rice bodies represent an uncommon, nonspecific, often intra-articular inflammatory process. Presumably, rice bodies represent the sequelae of microvascular infarcts of the joint synovium. However, rice bodies have been seen in pleural fluid, in the setting of bursitis, and within the tendon sheath. The etiology and prognostic significance of rice bodies are not clear. MRI is the diagnostic imaging modality of choice for the evaluation of rice body formation. Here we present a case of a 28-year-old female with a history of rheumatoid arthritis (RA) who presented to her primary care physician with a palpable mass around her right shoulder which was presumed to be a lipoma. An initial ultrasound showed a fluid filled structure with internal debris. Subsequent MRI evaluation was confirmatory for subacromial-subdeltoid bursitis with rice body formation. The salient point of this report is to highlight the importance of patient-specific differential diagnosis. While lipomas are a very common benign soft tissue tumor, patients with RA often have disease-specific sequelae that should be included in the diagnostic deliberation. Thus, when ordering diagnostic testing for patients with a palpable mass and rheumatoid arthritis, MRI--possibly preceded by conventional radiography--is the most appropriate diagnostic algorithm.

Highlights

Rice body formation represents an uncommon, nonspecific, inflammatory process [1,2,3]
Formation of rice bodies is most commonly associated with rheumatoid arthritis (RA), tuberculosis (TB), juvenile arthritides, seronegative arthritis, osteoarthritis, septic joint, trauma, and chronic bursitis [1,2]
Because rice bodies have been found in multiple extra-articular locations, some believe that activation of fibroblasts leads to collagen formation which subsequently becomes encased in fibrin [1]

Summary

Introduction

Rice body formation represents an uncommon, nonspecific, inflammatory process [1,2,3]. Because rice bodies have been found in multiple extra-articular locations, some believe that activation of fibroblasts leads to collagen formation which subsequently becomes encased in fibrin [1]. US demonstrates a well-circumscribed, mildly hypoechoic 7.8 cm mass abutting the deltoid muscle (black arrowheads) with multiple internal hyperechoic 'flecks' (white arrows). A T2 fat-saturated sequence demonstrates a 10.6 cm hyperintense fluid collection (white arrowheads) with multiple foci of internal debris, consistent with rice body formation (black arrows). This appearance is consistent with a fluid collection with foci of internal debris most consistent with a diagnosis of rheumatoid-arthritis-associated subacromial-subdeltoid bursitis with rice body formation. No reference to the patient's identity was made at any stage during data analysis or in the report

Discussion

Conclusions

Disclosures