"A very unusual case of recurrence of desmoplastic fibroblastoma": a case report.

Introduction: Desmoplastic fibroblastoma is a rare benign soft-tissue tumor which is typically painless and slow-growing, commonly found in the extremities. Despite its benign nature, recurrence is rare, and it generally shows favorable outcomes. Case Summary: A 34-year-old male first noticed a painless, slow-growing mass on his left lower back 4 years ago. Two years ago, he underwent a wide local excision of the mass, which was diagnosed as desmoplastic fibroblastoma. However, the mass recurred and progressively enlarged over time. He presented again with the recurrent mass, which was excised a second time. Histopathological examination confirmed the recurrence of desmoplastic fibroblastoma. Discussion: Desmoplastic fibroblastoma usually has an excellent prognosis, with no reported recurrences. However, in this case, recurrence was observed, which is uncommon. The recurrence may be attributed to factors such as incomplete excision due to the tumor's difficult location or inherent biological characteristics of the tumor cells. This rare occurrence warrants further investigation into potential contributing factors for recurrence. Conclusion: This case highlights the rare recurrence of desmoplastic fibroblastoma following initial excision. While the tumor generally has an excellent prognosis, this recurrence emphasizes the importance of long-term follow-up.