Visit: Pulmonary Malignant Fibrous Histiocytoma

Clinicopathological variants:

1.Storiform-Pleomorphic; 2.Myxofibrosarcoma  3.Inflammatory;  4.Giant cell ; 5.Angiomatoid    

 Path Quiz Case No 11: History and  images:

These are usually located in the extremites(mostly subcutaneous in location)and are associated with better prognosis.
Macroscopically the tumour has a gelatinous appearance.
Microscopic features:     Image1 ; Image2 ; Image3
- Hypocellular area containing
     i) Hyperchromatic spindle or stellate cells.
    ii) Delicate blood vessels are prominent.
- Abundant  acid mucopolysaccharide (mainly hyaluronic acid) is present in the matrix .
-The high grade area shows features of pleomorphic MFH.
- Atleast  5 -10% of the tumour must show myxoid areas.
-The tumour cells resemble lipoblasts but contain acid mucin and not lipid in the cytoplasmic vacuoles(pseudolipoblasts).
Differential diagnosis- Visit: Myxoid tumours of Soft Tissue:
-Myxoid liposarcoma (lipoblasts & vessels with branching pattern present,less pleomorphic.)
-Intramuscular myxoma- no pleomorphism
-Superficial angiomyxoma- "    "
-Low grade fibromyxoid sarcoma  (less vascular,less pleomorphic and less uniformly myxoid)
-Myxoid variants of nerve sheath tumour and smooth muscle tumour- (immunohistochemistry plays an important role in establishing the final diagnosis)  

Abstracts: -Malignant fibrous histiocytoma: pleomorphic sarcoma NOS or pleomorphic fibrosarcoma. Pathologe. 2005 Mar;26(2):127-33 - Pleomorphic malignant fibrous histiocytoma: fact or fiction? A critical reappraisal based on 159 tumors diagnosed as pleomorphic sarcoma. Am J Surg Pathol. 1992 Mar;16(3):213-28 -Myofibroblastic differentiation in malignant fibrous histiocytoma (pleomorphic myofibrosarcoma): a clinicopathological study. Histopathology 2001;38 (6): 499-509

Slow growing  nodular or cystic tumour  which is commonly located in the superficial soft tissue of the limbs.
Low grade malignant tumour with a tendency for local recurrence and distant metastasis.

Microscopic features:
- 1. Solid nests of fibroblast like and histiocyte like cells.
- 2. Large blood filled cystic spaces and areas of
  haemorrhage.
- 3. Lymphoplasmacytic infiltrate is present.
These may form lymphoid follicles at the periphery (features resemble a  lymphnode).
Immunohistochemistry:  Desmin positive; muscle actin(HHF-35) positive ; SMA negative; CD68 usually positive.

Differential diagnosis:
-Aneurysmal variant of dermatofibroma- Desmin (-).Polymorphic population of cells.
-Nodular Kaposi's sarcoma &  Spindle cell haemangioendothelioma in some cases.

Also termed 'Malignant giant cell tumour of soft parts.' 
Usually located in the  skeletal muscle of the extremities. Superficial tumours (subcutis or fascia) have a better prognosis than deeply situated( subfascial) tumours.
Microscopic features:
- Multinodular tumour composed of fibroblasts, histiocytes and osteoclast like giant cells.
- Focal osteoid or bone formation present at the periphery.
- Stromal haemorrhage is present
- Cells display pleomorphism and mitotic figures
are conspicuous.
- When neoplastic osteoid and bone formation is prominent it is justifiable to call the lesion giant cell variant of soft tissue osteosarcoma. CLICK HERE
- Leiomyosarcoma with osteoclast like giant cell is a subgroup of this variant.

Differential diagnosis: Carcinoma (lung, thyroid pancreas);  other sarcomas with giant cells ; rarely melanoma.

This rare variant is usually located in the retroperitoneum. The tumour has a poor prognosis.
Microscopic features:
- A dense diffuse neutrophilic infiltrate unassociated with tissue necrosis, admixed with xanthoma cells  and  tumour cells.
-Phagocytosis of neutrophils by the tumour cells 
-Some tumour cells display bizarre atypical nuclei others have a more bland appearance.
-Focal storiform fibrous areas  
-Multinucleate or Reed Sternberg like cells may be present

Differential diagnosis: Similar features are noted in :-
Metastatic carcinoma from large bowel,lung or kidney ,in irradiated osteosarcoma, other sarcomas (eg. leiomyosarcoma), T-cell lymphoma , histiocytic lesions, xanthogranulomatous pyelonephritis.

Inflammatory malignant fibrous histiocytomas and dedifferentiated liposarcomas: histological review, genomic profile, and MDM2 and CDK4 status favour a single entity.J Pathol. 2004;203(3):822-30

-Inflammatory malignant fibrous histiocytoma: distinction from Hodgkin's disease and non-Hodgkin's lymphoma by a panel of leukocyte markers.Mod Pathol. 1997 May;10(5):438-42

- Inflammatory leiomyosarcoma: a morphological subgroup within the heterogeneous family of so-called inflammatory malignant fibrous histiocytoma. Histopathology. 1995 Dec;27(6):525-32 

-Spectrum of low-grade fibrosarcomas: a comparative ultrastructural analysis of low-grade myxofibrosarcoma and fibromyxoid sarcoma.
Ultrastruct Pathol. 2004 Sep-Dec;28(5-6):321-32

-Expression of smooth muscle markers in so called malignant fibrous histiocytomas.Journal of Clinical Pathology 2003;56:666-671

-Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update.Am J Dermatopathol. 2004 Apr;26(2):141-55

-Pleomorphic leiomyosarcoma: clinicopathologic and immunohistochemical study with special emphasis on its distinction from ordinary leiomyosarcoma and malignant fibrous histiocytoma.Am J Surg Pathol. 2001 Aug;25(8):1030-8

-Histological vascular invasion by tumors is a risk factor for distant metastasis in malignant fibrous histiocytoma. Anticancer Res. 2005 Mar-Apr;25(2B):1337-42

-Current topics in the diagnosis and treatment of malignant fibrous histiocytoma. Gan To Kagaku Ryoho. 2003 May;30(5):626-33