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)  

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