Chronic Thigh Pain in an Adolescent: A Case Report and Literature Review of Desmoplastic Fibroma, A Rare Benign Tumor

Abstract

Introduction: Desmoplastic fibroma (DF) is a very rare, benign but aggressive bone tumor. It makes up <0.1% of all bone tumors and is often mistaken for other conditions, such as bone cysts or giant cell tumors. DF can occur in different bones, but it is uncommon in the proximal femur. Because it looks like other bone diseases on X-rays, diagnosing it correctly can be difficult. Proper treatment is needed to prevent it from coming back. However, due to its rarity, treatment recommendations are largely based on individual case reports, limiting the ability to establish standardized protocols.

Case report: A 16-year-old boy had pain in his upper left thigh for 3 years. The pain was dull and got worse when he walked or put weight on his leg. X-rays showed a lytic lesion in his femur, which looked like a bone cyst. He underwent surgery where the lesion was scraped out, and bone grafting with a bio-composite was done along with dynamic hip screw fixation. Tests on the removed tissue confirmed DF. After surgery, he was gradually allowed to bear weight and was followed up for 3 years. While this case demonstrates a favorable outcome, it is important to acknowledge that individual responses to treatment may vary, and long-term recurrence risk remains uncertain.

Conclusion: Even though DF is benign, it can still cause problems if not treated properly. The retrospective nature of this report limits its ability to establish causality or determine the best treatment approach. Long-term follow-ups are necessary to make sure it does not come back. Further studies, including larger case series and comparative analyses, are needed to refine treatment strategies and assess long-term outcomes.

Keywords: Desmoplastic fibroma; bone grafting; bone tumor; curettage; dynamic hip screw fixation; femur.

Figure 1

X-ray (anteroposterior and lateral views) showing a lytic lesion in the proximal femur.

Figure 2

Non-contrast computed tomography and magnetic resonance imaging demonstrating a well-defined cystic lesion.

Figure 3

(a, b, c) Post-operative X-rays at 3 weeks, 6 months, and 3 years.

Figure 4

Histopathological examination showing hypocellular stroma composed of mature, bland fibroblasts separated by abundant collagen, favoring desmoplastic fibroma.

Figure 5

(a and b) : Satisfactory functional outcome at 3-year follow-up.