RESUMO
BACKGROUND: Fibrous hamartoma of infancy (FHI) is a rare disease of infancy with unknown etiology. The disease mainly involves soft tissue, has no specific clinical manifestations, and is difficult to diagnose. At present, the diagnosis is mainly confirmed by histopathological examination, and the main treatment is surgical resection of the pathological tissue, which is prone to recurrence. CASE SUMMARY: A five-month-old female patient was admitted to our hospital with swelling in the right calf. Two biopsies were performed in our hospital and another hospital, respectively, confirming the diagnosis as fibrous hamartoma. After exclusion of surgical contraindications, resection was performed with clear margins of 1 cm. Radiographic examination showed tumor recurrence more than four months after the operation, and surgery was performed again to extend the resection margins to 1.5 cm. The patient is recovering well, and after a follow-up of 36 mo, shows no signs of recurrence. CONCLUSION: Our case report demonstrates that FHI should be considered in the differential diagnosis for a lower extremity mass with bone destruction. For FHI with bone destruction and unclear boundaries, excision margins of 1.5 cm could be superior to margins of 1 cm.