Diffuse subcutaneous oxalosis masquerading as lower limb cellulitis
Article information
A 43-year-old female patient with primary hyperoxaluria type 1 (G170 R mutation) and stage 5 chronic kidney disease on thrice-weekly hemodialysis presented with gradual bilateral lower limb swelling, pain, and restricted movement. Examination revealed warm, tender lower limbs with limited movement of the knee and ankle joints. Laboratory results showed a hemoglobin level of 9 g/dL, white blood cell count of 4,710/mm3, platelet count of 157,000/mm3, serum creatinine level of 4.1 mg/dL, serum urea level of 41 mg/dL, and normal serum electrolytes. Ultrasonography of the bilateral lower limbs revealed diffuse subcutaneous edema. Venous Doppler imaging of the lower limbs indicated subcutaneous edema without deep vein thrombosis. Broad-spectrum antibiotics were administered for the presumed cellulitis. A peripheral angiogram showed extensive soft tissue calcification in the lower limbs (Fig. 1A), and punch biopsy of the subcutaneous tissue of the left calf revealed extensive oxalate crystals (Fig. 1B). Echocardiography revealed an ejection fraction of 60% and mild pulmonary artery hypertension. The patient’s serum oxalate level at admission was 128 µmol/L. She began prolonged dialysis five times weekly with pyridoxine supplementation (5 mg/kg). Laboratory analysis at the end of 1 month revealed lowered serum oxalate levels of 52 µmol/L after weekly five times hemodialysis. After 1 month, she showed symptomatic improvement, slight enhancement in movement range with physiotherapy, and resolution of bilateral leg swelling (Fig. 1C).
Imaging, histopathological, and clinical findings of extensive soft tissue calcification in the lower limbs.
(A) Peripheral angiogram showing extensive soft tissue calcification extending from thigh to the ankle region. (B) Hematoxylin and eosin-stained subcutaneous biopsy (×400) revealing extensive oxalate crystal deposition in the reticular dermis (black arrow). (C) Clinical picture showing bilateral lower limb with brawny induration.
Written informed consent was obtained from the patient prior to the submission of the article. Institutional ethics clearance was not required for this case report and the study was performed in accordance with the CARE reporting guidelines.
Notes
Conflicts of interest
All authors have no conflicts of interest to declare.
Acknowledgments
The authors acknowledge Dr. Sunil Kumar, a consultant pathologist at MGM Hospitals, Chennai, for providing the pathological image.
Data sharing statement
The data presented in this study are available from the corresponding author upon reasonable request.
Authors’ contributions
Conceptualization, Data curation, Investigation, Methodology, Resources, Visualization: GGM, AA
Writing–original draft: GGM, AA
Writing–review & editing: GGM, AA
All authors read and approved the final manuscript.