Malignant Fibrous Histiocytoma

By admin Last updated Feb 8, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Malignant Fibrous Histiocytoma

Malignant Fibrous Histiocytoma

Frank J. Frassica MD

Basics

Description

MFH is an uncommon, malignant, primary mesenchymal tumor of soft tissue or bone that resembles fibrosarcoma.
In primary MFH of bone, the long bones are affected most commonly.
Classification: Several subtypes have been described, but typing has not been shown to have prognostic implications.

General Prevention

No preventive measures are known.

Epidemiology

Individuals can be affected at any age, but the tumor mainly occurs in the 5th–7th decades.
No real gender predominance, although a slight male predominance may occur (1).

Incidence

An uncommon primary bone tumor:
- The Mayo Clinic (Rochester, MN) has recorded 83 cases of MFH, representing 1% of the primary bone tumors (2).
In contrast, MFH is the most common soft-tissue sarcoma in adults.

Risk Factors

This tumor may arise as a complication of
pre-existing bone disease (e.g., Paget disease) within a bone infarct,
or from irradiation.
Up to 25% of cases are believed to be secondary (3).

Genetics

No known correlation exists.

Etiology

The cause is unknown.

Diagnosis

Signs and Symptoms

Identical to those of other primary bone tumors
Symptoms include pain and swelling, which is progressive.
Patients often are symptomatic for 3–6 months before diagnosis.

Physical Exam

The physical examination may be normal or may show only subtle findings.
When the tumor has penetrated the bone, a soft-tissue mass may be felt.
Muscle atrophy in the involved extremity is common.

Tests

Lab

The serum alkaline phosphate level may be increased secondary to bone destruction.

Imaging

Lytic bone destruction has a moth-eaten or permeative pattern.
- Reactive bone formation may be present.
Large lesions may show soft-tissue extension or may be complicated by a pathologic fracture.
Occasionally, lesions may show focal areas of calcification.

Pathological Findings

Grossly, these tumors appear fibrous.
Light microscopy reveals spindle-cell stroma with a characteristic “storiform pattern” (irregularly whorled).
Histiocytes with slightly foamy cytoplasm and multinucleated giant cells also are prominent features.
Any chondroid or osteoid matrix production by the tumor cells excludes the diagnosis of MFH.

Differential Diagnosis

Metastatic disease
Myeloma
Lymphoma
Other primary mesenchymal tumors
Osteosarcoma
Fibrosarcoma

Treatment

General Measures

MFH typically is radioresistant, but preoperative chemotherapy may improve the surgical outcome.
Any patient in whom the diagnosis of MFH
is suspected should be referred to a musculoskeletal oncologist for
additional evaluation and treatment.

Special Therapy

Physical Therapy

Physical therapy is used extensively after limb salvage surgery or amputation.

Medication

Preoperative and postoperative chemotherapy are used to minimize the risk of systemic metastasis.

Surgery

In the past, amputation was the mainstay of therapy for lesions in the appendicular skeleton.
With recent refinements in surgical
technique, limb salvage surgery with prosthetic or allograft
reconstruction frequently is an option.

P.245

Follow-up

Disposition

Issues for Referral

Patients are monitored carefully for the development of pulmonary metastases or local recurrence.
- Pulmonary surveillance:
  - Patients undergo serial chest CT scans every 3 months for 2 years and then every 6 months for 3 more years.
  - If metastases develop, patients are referred to a medical oncologist and thoracic surgeon.
- Local control surveillance:
  - Patients are followed with serial
    radiographs, physical examinations, and sometimes CT/MRI scans (not
    possible in the presence of metal hardware) at 6-month intervals.
  - If local recurrence develops, patients are referred to a medical oncologist and thoracic surgeon.

Prognosis

MFH is a high-grade bone sarcoma with a >50% risk of pulmonary metastasis (2).

Complications

Recurrence and metastasis are the most feared complications.

References

1. Dorfman HD, Czerniak B. Fibrous and fibrohistiocytic lesions. In: Bone Tumors. St. Louis: Mosby, 1998:492–558.

2. Nishida J, Sim FH, Wenger DE, et al. Malignant fibrous histiocytoma of bone. A clinicopathologic study of 81 patients. Cancer 1997;79:482–493.

3. McCarthy
EF, Frassica FJ. Primary bone tumors. In: Pathology of Bone and Joint
Disorders: With Clinical and Radiographic Correlation. Philadelphia: WB
Saunders, 1998:195–275.

Miscellaneous

Codes

ICD9-CM

171.3 Malignant fibrous histiocytoma

Patient Teaching

Patients with lower extremity lesions should be limited
to partial weightbearing until referral to an oncologist, to avoid the
possibility of pathologic fracture.

FAQ

Q: Do patients with MFH need surgery?

A: MFH of the bone is treated by wide resection of the bone. In addition, most patients are treated with chemotherapy.