Epithelial Malignant Tumours: Workshop 9

Epithelial malignant tumours Workshop 9

Carcinomas • •

They are malignant tumors derived from epithelial tissues. Histogenetic classification: two major categories:  Epidermoid carcinoma with origin in:  Epidermis  Epidermoid mucosa  Epidermoid metaplasia

 Adenocarcinoma with origin in the glandular epithelia of cavitary organs and endocrine and exocrine parenchymas

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After degree of differentiation of the tumoral cells there are four main types:    

Differentiated Moderate differentiated Poor differentiated Undifferentiated / anaplastic  Anaplasia = total loss of differentiation

Microscopy • • • • •

The morphology of cancerous cells Squamocellular or epidermoid carcinoma Basocellular carcinoma Differentiated adenocarcinoma of colon Metastasis of adenocarcinoma in lymph node.

The morphology of cancerous cells

Cellular and nuclear abnormalities: • Cellular and nuclear pleomorphism • Various cellular and nuclear size • The change of nucleo/cytoplasmic ratio (1/4 1/1) • Nuclear hypercromasia • Single or multiple nucleoli • Atypical mitoses

Keratinized epidermoid carcinoma – skin • Is a malignant tumor with origin in epidermis • The tumor cells destroy the basal membrane and infiltrate the connective tissue of the dermis

Keratinized epidermoid carcinoma – skin • Islands of polygonal atypical cells, that resemble the stratum spinosum of the epidermis, are separated by a reduced connective stroma • By differentiation the tumoral cells fill with keratin disposed as concentric lamellae (keratin pearls)

Basocellular carcinoma •Is a particular form of cutaneous carcinoma • Origin: basal layer of epidermis and appendageal glands • The tumor destroys the basal membrane and infiltrate the connective tissue of dermis

Basocellular carcinoma • The tumour is composed by tumoral islands separated by a reduced stroma •The tumoral islands are composed from tumoral cells resembling with basal layer cells having a characteristic disposition:  in palisade at the periphery  disordered appearance in the center of the tumoral islands

The tumor doesn’t metastasize and is radiosensitive

Well differentiated adenocarcinoma of colon

• The tumor origin is in the glandular epithelium of the colon. • The tumor penetrates the muscularis mucosae and infiltrates the submucosa and muscular layer.

Well differentiated adenocarcinoma of colon •

The tumor is composed from:  Tubular elements separated by a reduced stroma.  The tumoral glands are lined by an atypical epithelium disposed on one or multiple layers with an irregular lumen.

Lymph node metastasis of adenocarcinoma • The tumoral cells, reaching to the lymph node by lymphatic way, colonize the subcapsular sinus and than invade the entire lymph node, where they form tumoral glands limited by an atypical epithelium.