Fibrosarcoma

Fibrosarcoma is a tumor of connective tissue origin that can develop from the subcutaneous tissue, fascia, tendons, and intermuscular connective tissue.

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Pathomorphology of fibrosarcoma

Pathomorphology depends on the prevalence of one or another type of cells and the degree of their differentiation. A.V. Smolyannikov (1982) histologically distinguishes two types of fibrosarcoma: differentiated and poorly differentiated.

Differentiated fibrosarcoma

Differentiated fibrosarcoma is characterized by the presence of a large number of collagen fibers and the predominance of spindle-shaped elements with a regular arrangement of cellular fibrous strands. However, even in this form, various degrees of anaplasia and cell polymorphism can be detected.

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Poorly differentiated fibrosarcoma

Low-differentiated fibrosarcoma, on the contrary, is characterized by the predominance of cellular elements over fibrous substance. There is marked polymorphism of cells, hyperchromatosis of nuclei and the presence of pathological mitoses. Anaplastic cells have lumpy nuclei, the fusion of which results in the formation of multinucleated giant cells. Large areas consisting of polygonal cells resembling epithelioid cells are encountered. In some cases, this type of cells predominates, which gives grounds for some authors to distinguish a special form of fibrosarcoma - epithelioid cell. The nuclei of epithelioid cells are in most cases large, light, but can also be polymorphic. Electron microscopy reveals dilated cisterns of the endoplasmic reticulum, polyribosomes, microfilaments located in the perinuclear zone, as well as lysosomes and pinocytotic vesicles along the cytoplasmic membrane. Sometimes epithelioid and spindle-shaped cells form biphasic or pseudoglandular structures. Epithelioid cells often undergo necrosis, which is why this variant of fibrosarcoma has extensive foci of tumor decay. The amount of fibrous substances in low-differentiated sarcoma varies widely. Foci of myxomatous transformation may be encountered, sometimes extensive, as a result of which this variant is sometimes distinguished as a special form called "myxosarcoma".

Fibrosarcoma is differentiated primarily from Darier-Ferrand dermatofibrosarcoma. However, the latter is located only in the dermis and is characterized by moire structures. Malignant histiocytoma, unlike fibrosarcoma, contains a large number of giant cells in addition to polymorphic cells.

Symptoms of fibrosarcoma

Deep in the skin or subcutaneous tissue, nodes of various sizes appear, covered with normal or bluish-red skin, often with ulceration. The tumor occurs in people of both sexes, at any age, including children and even newborns, most often on the extremities, but sometimes on the trunk. It gives lymphogenous and hematogenous metastases.