(Kiosk 6) Hyaline Fibromatosis Syndrome: A Case Report

Case Diagnosis: A 5-month-old female diagnosed with infantile onset Hyaline Fibromatosis Syndrome while admitted to inpatient rehabilitation.

Case Description or Program Description: A 5-month-old full term female infant with failure to thrive (FTT), multiple joint contractures, and a neck hemangioma was referred to acute care by her general pediatrician. She received a nasogastric tube and X-rays of the extremities demonstrated mild periosteal findings. Differentials included neonatal onset multi-inflammatory disease or chronic infantile neurological cutaneous syndrome. The patient was then discharged to acute inpatient rehabilitation. There, she developed diffuse subcutaneous nodules, perioral rashes, and worsening painful joint contractures refractory to gabapentin. She was, subsequently, unable to participate in therapy. Her rehabilitation course was complicated by respiratory viral illness necessitating acute care transfer. At acute care, she underwent Nissen fundoplication, gastrostomy tube placement, and whole genome sequencing.

Setting: Inpatient Pediatric Rehabilitation Hospital

Assessment/Results: Genetic testing revealed mutations on ANTXR2 gene, consistent with Hyaline Fibromatosis Syndrome (HFS). Patient was readmitted to inpatient rehabilitation where her gabapentin was increased, and she was prescribed bilateral Benik braces. Pain and irritability improved. The patient was also able to engage her upper extremities more and tolerate PO feeds. She was discharged home with outpatient follow up.

Discussion (relevance): HFS is a rare autosomal recessive disorder characterized by hyaline tissue deposits due to mutations on ANTXR2. There are two forms, juvenile hyaline fibromatosis, which presents with a milder course between 2-5 years old, and infantile systemic hyalinosis, which presents in infancy with severe symptoms and earlier mortality. Symptoms include cutaneous nodules, perianal plaques, hyperpigmented macules over bony prominences, gingival hypertrophy, joint contractures, recurrent infections, and FTT, as seen here.

Conclusions: Although rare, HFS should be a potential differential for patients with progressive joint contractures without radiographic evidence of bone lesions, FTT, and cutaneous nodules. Furthermore, interventions including bracing and pain modulation can significantly improve quality of life in HFS patients.