The second form occurs in children and adolescents; it may affect several generations of the same family, and is often multiple, there being a combination of thickened yellow patches of skin and projecting tumours, some of which may attain a considerable size (Figs. 48 and 49).
On section, the tumour tissue presents a brilliant orange or saffron colour.
There is no indication for removing the tumours unless for the deformity which they cause; exposure to the X-rays is to be preferred to operation.
[Ill.u.s.tration: FIG. 49.--Zanthoma showing Subcutaneous Tumours on b.u.t.tocks. From same patient as Fig. 48.]
#Chondroma.#--A chondroma is mainly composed of cartilage. Processes of vascular connective tissue pa.s.s in between the nodules of cartilage composing the tumour from the fibrous capsule which surrounds it. On section it is of a greyish-blue colour and semi-translucent. The tumour is firm and elastic in consistence, but certain portions may be densely hard from calcification or ossification, while other portions may be soft and fluctuating as a result of myxomatous degeneration and liquefaction. These tumours grow slowly and painlessly, and may surround nerves and arteries without injuring them. They may cause a deep hollow in the bone from which they originate. All intermediate forms between the innocent chondroma and the malignant chondro-sarcoma are met with.
Chondroma may occur in a multiple form, especially in relation to the phalanges and metacarpal bones. When growing in the interior of a bone it causes a spindle-shaped enlargement of the shaft, which in the case of a phalanx or metacarpal bone may resemble the dactylitis resulting from tubercle or syphilis. A chondroma appears as a clear area in a skiagram.
A _skiagram_ of a bone in which there is a chondroma shows a clear rounded area in the position of the tumour, which must be differentiated from similar clear areas due to other kinds of tumour, especially the myeloma; when it has undergone calcification or ossification, it gives a shadow as dark as bone.
[Ill.u.s.tration: FIG. 50.--Chondroma growing from infraspinous fossa of Scapula.]
[Ill.u.s.tration: FIG. 51.--Chondroma of Metacarpal Bone of Thumb.]
_Treatment._--In view of the unstable quality of the chondroma, especially of its liability to become malignant, it should be removed as soon as it is recognised. In those projecting from the surface of a bone, both the tumour and its capsule should be removed. If in the interior, a sufficient amount of the cortex should be removed to allow of the tumour being sc.r.a.ped out, and care must be taken that no nodules of cartilage are left behind. In multiple chondromas of the hand, when the fingers are crippled and useless, exposure to the X-rays should be given a trial, and in extreme cases the question of amputation may have to be considered. When a cartilaginous tumour takes on active growth, it must be treated as malignant.
The chondromas that are met with at the ends of the long bones in children and young adults form a group by themselves. They are usually related to the epiphysial cartilage, and it was suggested by Virchow that they take origin from islands of cartilage which have not been used up in the process of ossification. They are believed to occur more frequently in those who have suffered from rickets. They have no malignant tendencies and tend to undergo ossification concurrently with the epiphysial cartilage from which they take origin, and const.i.tute what are known as _cartilaginous exostoses_. These are sometimes met with in a multiple form, and may occur in several generations of the same family. They are considered in greater detail in the chapter dealing with tumours of bone.
Minute nodules of cartilage sometimes form in the synovial membrane of joints and lining of tendon sheaths and bursae: they tend to become detached from the membrane and const.i.tute loose bodies; they also undergo a variable amount of calcification and ossification, so as to be visible in skiagrams. They are further considered with loose bodies in joints.
Cartilaginous tumours in the parotid, submaxillary gland, and t.e.s.t.i.c.l.e belong to a cla.s.s of "mixed tumours" that will be referred to later.
#Osteoma.#--The true osteoma is composed of bony tissue, and originates from the skeleton. Two varieties are recognised--the spongy or cancellous, and the ivory or compact. The _spongy_ or _cancellous osteoma_ is really an ossified chondroma, and is met with at the ends of the long bones (Fig. 52). From the fact that it projects from the surface of the bone it is often spoken of as an _exostosis_. It grows slowly, and rarely causes any discomfort unless it presses upon a nerve-trunk or upon a bursa which has developed over it. The Rontgen rays show a dark shadow corresponding to the ossified portion of the tumour, and continuous with that of the bone from which it is growing (Fig. 138). Operative interference is only indicated when the tumour is giving rise to inconvenience. It is then removed, its base or neck being divided by means of the chisel. The multiple variety of osteoma is considered with the diseases of bone.
The bony outgrowth from the terminal phalanx of the great toe--known as the _subungual exostosis_--is described and figured on p. 404. Bony projections or "spurs" sometimes occur on the under surface of the calcaneus, and, projecting downwards and forwards from the greater process, cause pain on putting the heel to the ground.
[Ill.u.s.tration: FIG. 52.--Cancellous Osteoma of lower end of Femur.]
The _ivory_ or _compact osteoma_ is composed of dense bone, and usually grows from the skull. It is generally sessile and solitary, and may grow into the interior of the skull, into the frontal sinus, into the cavity of the orbit or nose, or may fill up the external auditory meatus, causing most unsightly deformity and interference with sight, breathing, and hearing.
Bony formations occur in _muscles and tendons_, especially at their points of attachment to the skeleton, and are known as false exostoses; they are described with the diseases of muscles.
#Odontoma.#--An odontoma is composed of dental tissues in varying proportions and different degrees of development, arising from tooth-germs or from teeth still in process of growth (Bland Sutton).
Odontomas resemble teeth in so far that during their development they remain hidden below the mucous membrane and give no evidence of their existence. There then succeeds, usually between the twentieth and twenty-fifth years, an eruptive stage, which is often attended with suppuration, and this may be the means of drawing attention to the tumour. Following Bland Sutton, several varieties of odontoma may be distinguished according to the part of the tooth-germ concerned in their formation.
The _epithelial odontoma_ is derived from persistent portions of the epithelium of the enamel organ, and const.i.tutes a multilocular cystic tumour which is chiefly met with in the mandible. The cystic s.p.a.ces of the tumour contain a brownish glairy fluid. These tumours have been described by Eve under the name of multilocular cystic epithelial tumours of the jaw.
The _follicular odontoma_, also known as a _dentigerous cyst_, is derived from the distension of a tooth follicle. It const.i.tutes a cyst containing a viscid fluid, and an imperfectly formed tooth is often found embedded in its wall. The cyst usually forms in relation to one of the permanent molars, and may attain considerable dimensions.
The _fibrous odontoma_ is the result of an overgrowth of fibrous tissue surrounding the tooth sac, which encapsulates the tooth and prevents its eruption. The thickened tooth sac is usually mistaken for a fibrous tumour, until, after removal, the tooth is recognised in its interior.
_Composite Odontoma._--This is a convenient term to apply to certain hard dental tumours which are met with in the jaws, and consist of enamel, dentine, and cement. The tumour is to be regarded as being derived from an abnormal growth of all the elements of a tooth germ, or of two or more tooth germs, indiscriminately fused with one another. It may appear in childhood, and form a smooth unyielding tumour, often of considerable size, replacing the corresponding permanent tooth. It may cause a purulent discharge, and in some cases it has been extruded after sloughing of the overlying soft parts. Many examples of this variety of odontoma, growing in the nasal cavity or in the maxillary sinus, have been erroneously regarded as osteomas even after removal.
On section, the tumour is usually laminated, and is seen to consist mainly of dentine with a partial covering of enamel and cement.
_Diagnosis._--Odontomas are often only diagnosed after removal. When attended with suppuration, the condition has been mistaken for disease of the jaw. Fibrous odontomas have been mistaken for sarcoma, and portions of the maxilla removed unnecessarily. Any circ.u.mscribed tumour of the jaw, particularly when met with in a young adult, should suggest the possibility of an odontoma. Skiagrams often give useful information both for diagnosis and for treatment.
_Treatment._--The solid varieties of odontoma can usually be sh.e.l.led out after dividing the overlying soft parts. In the follicular variety, it is usually sufficient to excise a portion of the wall, sc.r.a.pe out the interior, and remove any tooth that may be present. The cavity is then packed and allowed to heal from the bottom.
#Fibroma.#--A fibroma is a tumour composed of fibrous connective tissue.
A distinction may be made between the _soft fibroma_, which is comparatively rich in cells and blood vessels, and in which the fibres are arranged loosely; and the _hard fibroma_, which is composed of closely packed bundles of fibres often arranged in a concentric fashion around the blood vessels. The cut surface of the soft fibroma presents a pinkish-white, fleshy appearance, resembling the slowly growing forms of sarcoma; that of a hard fibroma presents a dry, glistening appearance, aptly compared to watered silk. The soft variety grows much more rapidly than the hard. In certain fibromas--in those, for example, which grow from the periosteum of the base of the skull and project into the naso-pharynx--the blood vessels are dilated into sinuses and have no proper sheaths; they therefore tend to remain open when divided, and to bleed excessively. Transition forms between soft fibroma and sarcoma are met with, so that in operating for their removal it is safer to take away the capsule along with the tumour, and the patient should be kept under observation in view of the risk of recurrence.
The skin--especially the skin of the b.u.t.tock--is one of the favourite seats of fibroma, and it may occur in a multiple form. It is met with also in the subcutaneous and intermuscular cellular tissue, and in the abdominal wall, where it sometimes attains considerable dimensions.
Various forms of fibroma are met with in the mamma and are described with diseases of that organ. The fibrous overgrowths in the skin, known as _keloid_ and _mollusc.u.m fibrosum_, and those met with in the _sheaths of nerves_, are described elsewhere. Fibroid tumours of the uterus are described with myoma.
_Diffuse fibroma_ or _Fibromatosis_, a.n.a.logous to lipomatosis, is met with in the connective tissue of the skin and sheaths of nerves, and const.i.tutes one form of neuro-fibromatosis; a similar change is also met with in the stomach and colon.
#Myxoma.#--A myxoma is composed of tissue of a soft gelatinous, semifluid consistence. The pure myxoma is extremely rare, and clinically resembles the lipoma. Myxomatous tissue is, however, frequently found in other connective-tissue tumours as a result of degeneration, for example, in cartilaginous tumours and in sarcomas.
Myxomatous tissue is also a prominent const.i.tuent of the "innocent parotid tumour." Mucous polypus of the nose, which is often described as a myxoma, is merely a pendulous process of dematous mucous membrane.
[Ill.u.s.tration: FIG. 53.--Myeloma of Shaft of Humerus, causing pathological fracture. (Mr. J. W. Struthers" case.)
(The unusual site of the tumour is to be noted.)]
#Myeloma.#--A myeloma is composed of large multinuclear giant cells surrounded by round and spindle cells. The cut surface of the tumour presents a deep red or maroon colour. While occasionally met with in tendon sheaths and bursae, and is then of an orange-yellow colour, the myeloma occurs most frequently in the cancellous tissue at the ends of the long bones, its favourite site being the upper end of the tibia.
Although formerly cla.s.sified as a sarcoma, it is the exception for it to present malignant features, and it can usually be extirpated by local measures without fear of recurrence. The diagnosis, X-ray appearances, and the method of removal are considered with the diseases of bone.
Sometimes the myeloma is met with in multiple form in the skeleton, in a.s.sociation with an unusual form of protein in the urine (Bence Jones).
#Myoma.#--A myoma is composed of non-striped muscle fibres. A pure myoma is very rare, and is met with in organs possessed of non-striped muscle, such as the stomach, intestine, urinary bladder, and prostate. In the uterus, which is the most common situation, these tumours contain a considerable admixture of fibrous tissue, and are known as _fibroids_ or _fibro-myomas_. They present on section a fasciculated appearance, which may resemble that of a section of b.a.l.l.s of cotton (Fig. 54). They are encapsulated and vascular, frequently attain a large size, and may be single or multiple. While they may occasion neither inconvenience nor suffering, they frequently give rise to profuse haemorrhage from the uterus, and may cause serious symptoms by pressing injuriously on the ureters or the intestine, or by complicating pregnancy and parturition.
The #Rhabdomyoma# is an extremely rare form of tumour, met with in the kidney, uterus, and t.e.s.t.i.c.l.e. It contains striped muscle fibres, and is supposed to originate from a residue of muscular tissue which has become sequestrated during development.
[Ill.u.s.tration: FIG. 54.--Fibro-myoma of Uterus.
(Anatomical Museum, University of Edinburgh.)]
#Glioma.#--A glioma is a tumour composed of neuroglia. It is met with exclusively in the central nervous system, retina, and optic nerve. It is a slowly growing, soft, ill-defined tumour, which displaces the adjacent nerve centres and nerve tracts, and is liable to become the seat of haemorrhage and thus to give rise to pressure symptoms resembling apoplexy. The glioma of the retina tends to grow into the vitreous humour and to perforate the globe. It is usually of the nature of a glio-sarcoma and is highly malignant.
#Endotheliomas# take origin from the endothelium of lymph vessels and blood vessels, and serous cavities. They show great variation in type, partly because of the number of different kinds of endothelium from which they are derived, and partly because the new connective tissue which is formed is liable to undergo transformation into other tissues.
They may be soft or hard, solid or cystic, diffuse or circ.u.mscribed; they grow very slowly, and are almost always innocent, although recurrence has been occasionally observed. Cases of multiple endotheliomata of the skin have recently been described by Wise.
_Angioma_, _lymphangioma_, and _neuroma_ are described with the disease of the individual tissues.
MALIGNANT CONNECTIVE-TISSUE TUMOURS--SARCOMA
The term sarcoma is applied to any connective-tissue tumour which exhibits malignant characters. The essential structural feature is the predominance of the cellular elements over the intercellular substance or stroma, in which respect a sarcoma resembles the connective tissue of the embryo. The typical sarcoma consists chiefly of immature or embryonic connective tissue. It most frequently originates from fascia, intermuscular connective tissue, periosteum, bone-marrow, and skin, and forms a rounded or nodulated tumour which appears to be encapsulated, but the capsule merely consists of the condensed surrounding tissues, and usually contains sarcomatous elements. The consistence of the tumour depends on the nature and amount of the stroma, and on the presence of degenerative changes. The softer medullary forms are composed almost exclusively of cells; while the harder forms--such as the fibro-, chondro-, and osteo-sarcoma--are provided with an abundant stroma and are relatively poor in cells. Degenerative changes may produce areas of softening or liquefaction which result in the formation of cystic cavities in the interior of the tumour. The colour depends on the amount of blood in the tumour, and on the presence of the products of degeneration.
The blood vessels are usually represented by mere c.h.i.n.ks or s.p.a.ces between the cells. This peculiarity accounts for the facility with which haemorrhage takes place into the substance of the tumour, the persistence of the bleeding when it is incised or ulcerates through the skin, and the readiness with which the sarcomatous cells are carried off and infect distant parts through the blood-stream. Sarcomas are devoid of lymphatics, and unless originating in lymphatic structures--for example, in the tonsil--they rarely infect the lymph glands. Minute portions of the tumour grow into the small veins, and, becoming detached, are transported by the blood-current to distant organs, where they are arrested in the capillaries and give rise to secondary growths. These are most frequently situated in the lungs, except when the primary growth lies within the territory of the portal circulation, in which case they occur in the liver. The secondary growths closely resemble the parent tumour. Sarcoma may invade an adjacent vein on such a scale that if the invading portion becomes detached it may const.i.tute a dangerous embolus. This may be observed in sarcoma of the kidney, the growth taking place along the renal vein until it projects into the vena cava.
[Ill.u.s.tration: FIG. 55.--Recurrent Sarcoma of Sciatic Nerve in a woman aet. 27. Recurrence twenty months after removal of primary growth.]
In its growth, a sarcoma compresses and destroys neighbouring parts, surrounds vessels and nerves, and may lead to destruction of the skin, either by invading it, or more commonly by causing sloughing from pressure. Inflammatory and suppurative changes may take place as a result of pyogenic infection following upon sloughing of the overlying skin or upon an exploratory incision. Once the skin is broken the tumour fungates through the opening. Sarcomas vary in malignancy, especially as regards rapidity of growth and capacity for dissemination. Certain of them, such as the so-called "recurrent fibroid of Paget," grow comparatively slowly, and are only malignant in the sense that they tend to recur locally after removal; others--especially the more cellular ones--grow with extreme rapidity, and are early disseminated throughout the body, resembling in these respects the most malignant forms of cancer. They are usually solitary in the first instance, although primary multiple growths are occasionally met with in the skin and in the bones.
Many varieties of sarcoma are recognised, according to its structural peculiarities. Thus, in virtue of the size and character of the cells, we have the _small round-celled_ and the _large round-celled_ sarcoma, the _small_ and the _large spindle-celled_, the _giant-celled_ and the _mixed-celled_ sarcoma. The _lympho-sarcoma_ presents a structure similar to that of lymph-follicular tissue, and the _alveolar sarcoma_ an arrangement of cells in alveoli resembling that seen in cancers. When there is a considerable amount of intercellular fibrous tissue, the tumour is called a _fibro-sarcoma_.
[Ill.u.s.tration: FIG. 56.--Fungating Sarcoma of Arm.