What is the treatment for fibrous histiocytoma?

Treatment of Fibrous Histiocytoma

Benign Fibrous Histiocytoma

For benign fibrous histiocytoma of bone, complete surgical curettage with bone grafting is the definitive treatment and prevents recurrence. 1

Surgical Approach for Bone Lesions

• Prophylactic curettage and bone grafting are indicated when there is local tumor expansion evidenced by cortical thinning, small cortical fissures, or pain, even in the absence of pathologic fracture 1
• Surgery should be restricted to the osteolytic area, which is sufficient to prevent recurrence 1
• This approach addresses the cardinal symptom of pain and prevents progression despite the benign nature of the lesion 1

Cutaneous Benign Fibrous Histiocytoma

• Complete excision is the treatment of choice for all cutaneous variants to minimize recurrence risk 2, 3
• Deep benign fibrous histiocytoma (subcutaneous or deep soft tissue) has a 22% local recurrence rate when marginally or incompletely excised 3
• Atypical fibrous histiocytoma shows higher recurrence rates than ordinary fibrous histiocytoma and requires complete excision 2
• Wide margins are critical: incomplete excision leads to recurrence in approximately 50% of cases for certain variants 4

Important Caveats

• While benign fibrous histiocytoma is generally considered benign, deep variants can rarely metastasize (5% in one series), particularly when tumors are large (>6 cm) or have necrosis 3
• Atypical variants with florid pleomorphism should not be overinterpreted as pleomorphic sarcoma, but complete excision remains essential 2

Malignant Fibrous Histiocytoma (Now Termed Undifferentiated Pleomorphic Sarcoma)

For malignant fibrous histiocytoma/undifferentiated pleomorphic sarcoma of bone, treatment follows osteosarcoma protocols with chemotherapy plus complete en bloc surgical resection. 5, 6

Bone Lesions

• Treatment strategies mimic osteosarcoma management: chemotherapy combined with complete en bloc resection including any soft tissue component 5, 6
• Full staging and biopsy are required before initiating treatment 5
• Pathological fractures are common and should be investigated before fixation 5
• These tumors are typically high-grade with metastasis rates of at least 50% 6

Soft Tissue Lesions

• Conservation surgery striving for negative margins combined with radiation therapy is the treatment of choice for soft tissue malignant fibrous histiocytoma 7
• Postoperative radiation (mean dose 62.8 Gy) or preoperative radiation (mean dose 50 Gy) provides acceptable local control 7

Margin Status Impact

• Negative surgical margins achieve 17% 10-year local recurrence rate 7
• Positive margins result in 39% 10-year local recurrence rate 7
• Prior local recurrence is an adverse factor, yielding 42% 10-year recurrence rate versus 22% without prior disease 7

Histologic Subtype Considerations

• Myxoid variant has distinctly better prognosis: 13% 10-year metastatic rate versus 40% for nonmyxoid tumors 7
• For myxoid tumors, significant metastatic risk appears only when exceeding 10 cm (8% vs 44% for tumors <10 cm vs >10 cm) 7
• For nonmyxoid tumors, size >5 cm significantly increases metastatic risk (23% vs 51% 10-year metastatic rates) 7

Systemic Therapy

• Patients with myxoid tumors do not require systemic therapy 7
• Patients with nonmyxoid disease exceeding 5 cm are at significant risk for metastases and should be considered for adjuvant treatment 7
• For soft tissue sarcomas including undifferentiated pleomorphic sarcoma, gemcitabine and docetaxel have shown activity 5

Key Clinical Pitfall

• It is not uncommon for spindle cell sarcomas to be reclassified as dedifferentiated chondrosarcoma or osteosarcoma after examining additional sections from the resection specimen 5, 6
• This underscores the importance of adequate tissue sampling and expert pathology review before finalizing treatment plans 5