ENCHONDROMA.
Enchondroma (from sma,Spots, cartilagi nous,) is the name recently proposed by Miller for a species of cartilaginous growth, not unknown to previous observers, but by many surgical writers confounded, under the erroneous name of " cartilaginous exestosis" (erroneous, if for no other reason, because the formation in question may spring from other tissues than bone), with products of essentially different character, and by some other authors described as colloid cancer.
When uncut, enchondrorna exhibits itself as a tumour of moderate size and spheroidal non-lobulated shape, encased in cellular mem brane, or (if it spring from bone) in perios teum, ossified or not. The section discovers a firmly gelatinous substance, rather pellucid, of very pale greyish or greenish yellow tint, set (without firm adhesion) in loculi inclined to spheroidal outline, varying in size, and having their walls formed of a dense dull white tissue (fig. 95). One of the rough marks of distinction between this growth and colloid cancer consists in the mode of arrangement of the walls of the loculi : in the latter, when fully grown, the walls seem cut across sharply at right angles with their course ; in the thr iller it is extremely common to find the walls exhibiting flat and extensive surfaces to the eye, as though the loculi had been opened to a very small extent only.
The general mass is firm ; when the invest. ment is periosteal or bony, proportionably increased. The intra-locular matter is in it self soft, yet has a sharp fracture. Bony matter in its interior of course increases its consistence, and may be formed of: I, the walls of the loculi converted into thin osseous plates, which give a crackling crispness to the mass; 2, particles of the spongy tissue of the original bone in which it has grown ; 3, sta lactifonn osteophy tes springing into its sub stance.
No appearance of vessels strikes the un assisted eye in these masses ; but von Wal ther and Weber (6'rNie and Walther's Journ., b. xxiii. s. 351.) are said by Miiller to have injected the walls of the loculi.
Microscopically examined, the fibrous por tion of the growth is found to be composed of transparent interwoven fibres. The jelly like part consists of cells several times larger than the red blood-corpuscle, generally speak ing, containing only nuclei in their interior, hut in some instances two or three sub-cells, each provided with its own nucleus. The
nuclei, flattened, oval or circular, vary in diameter. The cells (except in excessively rare cases) are in close contact with each other, and no inter-cell substance discern ible between them : the cartilaginous ma terial does not advance beyond the embryonic stage. Such is Mfiller's description ; but it is certain that tumours having the characters of enchondroma perfectly developed to the naked eye, and yieldina gelatin, may be wholly deficient in cartirage corpuscles, and contain simple granulated cells in a fibrous stroma.
Spiculated bone corpuscles are sometimes scattered through the tumour.
From this account it would appear, that although the endogenous mode of growth of the cells occurs occasionally in this forma tion, it is neither uniform nor constant ; their development proceeds more frequently from blastema ly ing outside such cells as are already evolved. The endogenous development was observed especially by Miiller in an enchon droma of the parotid gland. Whether the inter-cell substance is generated by thickening of the walls of the cells, or by the hardening of a blasteina unconnected, except in respect of proximity, with these, is matter of dispute. Enchondroma is essentially composed either of chondrin or of glutin ; of' the former in by far the greater number of cases ; of the latter, in Milller's specimen connected with the parotid gland, and in another connected with the ileum, recently added to the Uni versity College Collection.
The bones are the favourite seat of this growth. Miiller has collected thirty-six cases, in thirty-two of which those organs were af fected : the metacarpus and phalanges 25 times; the tibia 3 ; the ileum 1; the cranium I ; the ribs I, Of the four remaining tumours, I ex isted in the parotid ; 1 in the mamma of a dog ; 2 in the te.ticle. In its favourite seat — the metacarpus and phalanges — this dis ease produces singular distortion and irregular tuberontvess of the hand (fig. 96).