1200 - Diagnostic Challenges of Pigmented Villonodular Synovitis in a Nonverbal Patient with Severe Autism Spectrum Disorder

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

TS

Taylor J. Struble, MD

Resident Physician
Mary Free Bed Rehabilitation Hospital
Rockford, Michigan, United States

Co-Author(s)

VG

Valerie Garcia, BS

Medical Student
Michigan State University College of Human Medicine
Grand Blanc, Michigan, United States
NK

Naomi Kaplan, MBBS

Attending Physician
Mary Free Bed Rehabilitation Hospital
Grand Rapids, Michigan, United States

Submitter(s)

TS

Taylor J. Struble, MD

Mary Free Bed Rehabilitation Hospital
Rockford, Michigan, United States

Case Diagnosis: Pigmented villonodular synovitis (PVNS) is a rare, benign proliferative disorder of the synovium that often presents with joint pain, swelling, and decreased range of motion. Diagnosing musculoskeletal conditions in individuals with severe autism spectrum disorder (ASD), particularly those who are nonverbal, is uniquely challenging due to communication barriers, atypical pain expression, and overlapping behavioral manifestations. These barriers can further complicate the post-operative course and must be considered when discussing treatment options.

Case Description: We present a 32-year-old nonverbal female with severe ASD who was evaluated for progressive right knee pain and decreased ROM for approximately 1 year. Caregiver reported behavioral changes including gait abnormality and guarding, not improved with physical therapy and conservative management. Physical examination limited due to pain and anxiety, but revealed short stride, decreased ROM of right knee, with no joint effusion. Advanced imaging demonstrated synovial proliferation with a bulky lobulated intra-articular mass consistent with PVNS. Surgical intervention is still being considered, given caregiver concerns for postoperative recovery in the setting of ASD with body-focused repetitive behaviors, including skin picking, and subsequent risk of infection.

Discussions: This case illustrates the diagnostic complexity of musculoskeletal pathology in patients with neurodevelopmental disorders. Limited verbal communication may delay recognition of painful conditions, while behavioral changes can be misattributed to psychiatric or developmental causes. PVNS is rare, but the diagnostic principles highlighted here—integrating careful caregiver history, functional changes, and appropriate imaging—underscore broader challenges in providing comprehensive care to individuals with severe ASD. Early recognition and multidisciplinary collaboration are critical to avoid prolonged morbidity.

Conclusions: Physiatrists must maintain a broad differential diagnosis when evaluating functional or behavioral changes in nonverbal patients with neurodevelopmental disorders. This case emphasizes the importance of adapting diagnostic and treatment approaches in PM&R to meet the needs of this vulnerable population.