Giant-Cell Sarcoma is one in which there are found cells made up of a large amount of cytoplasm in which are numerous oval nuclei centrally located. The predominating cells may be round or spindle shaped. They are most commonly found in relation with bone and periosteum. When occurring on the jaw are sometimes referred to as epulis, although the same term may be applied to a simple fibrous tumor.

Fig. 43. - Alveolar Small Round-cell Sarcoma. Zeiss, Oc. 4; ob. c.

(McFarland).

This form is the least malignant of all the sarcomata.

Special names have been given to other forms of sarcoma on account of some special feature. Alveolar sarcoma is where either groups of round or spindle cells are surrounded by distinct bands of connective tissue. This form may very closely resemble carcinoma. Melanotic sarcoma is one of any type in which there is melanin present. This pigment may be found either in the cells or in the intercellular tissue. *

They occur in the skin, the choroid coat of the eye, and in the ciliary body.

Are very malignant, give widespread metastasis, and rapidly prove fatal. The liver is the common secondary seat, particularly after primary melanotic sarcoma of the eye.

Fig. 44. - Metastatic Melanosarcoma of the Peritoneum. X 320. (Dürck).

1, Nests of darkly pigmented polygonal cells; 2, cross-section of vessels.

Myxosarcoma

Myxosarcoma is one in which there is a marked mucoid degeneration present.

Angiosarcoma

Angiosarcoma is a growth that contains many blood-vessels. If the walls of these vessels or the neighboring cells undergo a hyaline degeneration, the sarcoma is spoken of as a cylindroma.

If the tissue with the exception of those cells in the immediate neighborhood of the vessels undergoes a mucoid change, the growth is called a myxangiosarcoma tubulare. Chloroma is a variety of sarcoma arising from the periosteum of the skull; is greenish in color. It may be that this form is more closely related to the tumor formations occurring in leukemia.

Fig. 45. - Perithelioma of the Retina (McFarland).

a, Blood-vessels surrounded by cells in a good state of preservation; b, degenerated portion of tumor.