Oral Carcinosarcoma

Carcinosarcoma Definition

A malignant neoplasm that contains elements of carcinoma (cancer of epithelial tissue, which is skin and tissue that lines or covers the internal organs) and sarcoma (cancer of connective tissue, such as bone, cartilage, and fat) so extensively intermixed as to indicate neoplasia of epithelial and mesenchymal tissue.

Source: National Institute of Health-USA

Synonyms

• Carcinosarcoma(Minkler et.al. 1970)
• Spindle-cell carcinoma or Pleomorphic Carcinoma(Ellis & Corio 1980,Zarbo et.al. 1986,Ellis et.al. 1987)
• Spindle-cell SCC
• Pseudosarcoma(Lane 1957)
• True malignant mixed tumour
• Sarcomatoid carcinoma

Epidemiology

Extremely RARE.

Head-and-neck sites ; in descending Frequency

Larynx

Oral cavity

Hypopharynx and pyriform sinus

Sinonasal tract

Oropharynx

Carcinosarcoma (CS) is sometimes found in other parts of the body.

Incidence is more common in the upper body, particularly the lungs

In oral cavity carcinosarcoma can arise from either salivary glands or oral mucosa.

Aetiology

Idiopathic

Radiation /trauma has been emphasized by some authors (Green & Bernier 1959)

Accumulation of genetic mutations could be a factor.

Clinical Features

Symptoms are often present for a short duration

Nearly all cases are described or received as;

• Polypoid masses .
• Mean size of about 2.0cm
• Frequently ulcerated.
• With a covering of fibrinoid necrosis.
• Firm and fibrous cut surface.
• (Similar to conventional SCC, most tumours are T1 lesions at presentation.)

These carcinosarcomas occur most frequently on the lower lip,tongue and alvelolar ridge in either polypoid,exophytic or endophytic configurations.

Surface ulceration is common with these tumors. As with any ulcerated lesion, these are likely to be infected and therefore may exude pus or contain abscess formation.

Cervical lymphadenopathy is infrequent,distant metastasis may/not present.

Investigations

MRI

CT

Scintigraphy

Histopathological investigations;

- Incisional biopsy

- Excisional biopsy

- Immunohistopathological investigations.

Ultra sound scanning to detect lymph node involvement.

Chest X-ray & Gastroendoscopy to detect distant metastases.

HISTOLOGY

Carcinosarcoma composed of heterologous malignant epithelial & stromal components which both fulfill histological criteria of malignancy.

Usually Sarcomatous component is predominent.

Biphasic presentation

Ulcerated

Carcinomatous component is either blended or in transition with sarcomatous component.

Hypercellularity

Variable patterns of spindle-cell growth in sarcomatous component

Pleomorphism

Increased mitotic figures

Carcinomatous component is usually

• Undifferentiated SCC
• Squamous cell carcinoma
• Poorly differentiated adenocarcinoma
• It may also include
• Adenoid cystic carcinoma
• Epithelial myoepithelial carcinoma
• Salivary duct carcinoma.

The sarcomatous component is usually,

Undifferentiated spindle cell sarcoma

Other reported sarcomatous elements include

• Fibrosarcoma
• Osteosarcoma
• Leiomyosarcoma
• Liposarcoma
• Follicular dendritic cell sarcoma
• Undifferentiated sarcoma
• Myxoid sarcomas
• Rhabdomyosarcoma
• Chondrosarcoma

Areas of squamous differentiation are most consistently identified at the base of the polypoid lesion, at the advancing margins, or within invaginations at the surface where the epithelium is not ulcerated or denuded.(Condition is same in our patient)

CS will often present with little invasion into the underlying stroma, as it is polypoid.

Extensive infiltration and tissue destruction are common, as is perineural invasion and angioinvasion. Lymphatic spread is less common.

Metastases to other sites or lymph nodes may show the carcinomatous or the sarcomatous components alone, or they may be mixed.

So its extremely difficult in making the correct diagnosis of this tumor from a small biopsy specimen.

It is well illustrated by varies diagnoses based on biopsy specimens.

Immunohistochemistry

Immunohistochemical markers are used in aid of diagnosis.

Eg; -Cytokeratin

- Vimentin

- S-100

- Actin

Cytokeratins are proteins of keratin-containing intermediate filaments found in the intracytoplasmic cytoskeleton of epithelial tissue.there fore carcinomatous componentwhich is derived from epithelial tissue is strongly positive for cytokeratin

Vimentin is a member of the intermediate filament family of proteins that is especially found in connective tissue. This filament is used as a marker for mesodermally derived tissues, and as such can be used as an immunohistochemical marker for sarcomas.

Immunohistochemistry for smooth muscle actin & vimentin reveals positivity in spindle cell component while the squamous cell component shows cytokeratin positivity.

S-100 is negative.

Our patient’s immunohistochemical profile

HISTOPATHOGENISIS

Two antithetical hypotheses have been advanced to explain the histogenesis of carcinosarcomas:

Multiclonal origin/ convergence hypothesis-arising from two or more stem cells

Monoclonal origin/ Divergence hypothesis-from a single totipotential stem cell that differentiates in separate epithelial and mesenchymal directions.

Recent immunohistochemical and chromosomal analyses appear to have settled this argument in favour of the monoclonal hypothesis.

But some of the cases showed a sharp demarcation between the carcinomatous & sarcomatous elements without transition zone & different immunohistochemical staining pattern of the two components for epithelial & mesenchymal markers which suggests a different cell origin for each tumor cell types.

However possibility remains that the demarcation may not signify a different origin, since carcinoma components are demarcated in some sarcomatoid carcinomas in which the sarcomatous component derives from metaplasia of the epithelial cells.

Treatment modalities for sarcomatoid carcinoma.

The primary treatment modality for sarcomatoid carcinoma should be the same as for squamous cell carcinoma which consists of;

SURGICAL EXCISION of the lesion with an adequate margin.

ADJUVANT IRRADIATION may be beneficial in patients who have positive surgical margin or who have nodal metastasis.

The role of the chemotherapy has not been established, but it may decrease the incidence of recurrence or metastasis of primarily sarcomatous tissue.

Prognosis

Mean survival time of those dead of the disease is

2 years.

No clinical or histomorphological characteristic other than distant metastasis was found to be a reliable prognostic indicator.