Adenomas arise in secretory glands, and resemble the structure from which they arise. They are encapsulated, and sometimes they secrete hormones which profoundly influence metabolism, as in the case of the thyroid, parathyroid and pancreas. Occasionaliy an adenoma contains a large proportion of fibrous tissue, e.g. the hard fibroadenoma in the breast, while in other situations, notably the pancreas and thyroid gland, cystic degeneration is common. Those arising from superficial glands of mucous membrane are liable to pedunculation, as in the case of a rectal ‘polyp,.
A papilloma consists of a central axis of connective tissue, blood vessels and lymphatics; the surface is covered by epithelium, either squamous, transitional, cuboidal or columnar, according to the site of the tumour. The surface may be merely roughened, or composed of innumerable delicate villous processes, as in the case of those occurring in the kidney, bladder and rectum. In these situations, papillomas resemble malignant rumours, as secondary growths arise by implantation and, sooner or later, the tumour becomes frankly malignant (Chapter 65). Other common sites for papillomas are the skin, the colon, the tongue and lip, t] vocal cords and the walls of cysts (particularly those the breast and ovary).
A true fibroma (containing only fibrous connective tissue) rare. Most fibromas are combined with other mesoderm tissues such as muscle (fibromyoma), fat (fibrolipoma) ai nerve sheaths (neurofibroma). Multiple rumours are n uncommon as, for example, in neurofibrornatosis (v Recklinghausen’s disease, ).
Fibromas are either hard or soft, depending on the propc non of fibrous to the other cellular tissue. Soft fibromas a common in the subcutaneous tissue of the face, and appear soft, brown swellings.
[This unusual type of flbroma occurs in the abdominal wall. An intraperitoneal form is associated with familial adenomato polyposis.
This overgrowth of fibrous tissue commonly occurs in scars, especially black people.
A lipoma is a slowly growing tumour composed of fat cells adult type. Lipomas may be encapsulated or diffuse. Tb occur anywhere in the body where fat is found and earn tl titles of the ‘universal tumour’ or the ‘ubiquitous tumour The head and neck area, abdominal wall and thighs are particularly favoured sites.
Encapsulatedlipomas are among the commonest of rumours. The characteristic features are the presence of a definite edge and lobulation. A sense of fluctuation may be obtained. As would be expected, a lipoma deeply situated is liable to be mistaken for other swellings. Most lipomas are painless, but some give rise to an aching sensation which may radiate.
Multiplelipomas are not uncommon. The rumours remain small or moderate in size, and are sometimes painful, in which case the condition is probably one of neurolipomatosis. Dercum ‘s disease (adiposis dolorosa), characterised
by tender deposits of fat, especially on the trunk, is an associated condition.
Should the lipoma contain an excessive amount of fibrous tissue, it is termed a fibrolipoma.In other cases, considerable vascularity is present, often with telangiectasis of the overlying skin, in which case the tumour is a naevolipoma.Large lipomas of the thigh, the shoulder and the retroperitoneum occasionally undergo sarcomatous changes. Myxomatous degeneration, saponification and calcification sometimes occur in lipomas of long duration.
Clinically, circumscribed lipomas are classified according to their Situation.
• Subcutaneous. Commonly found on the shoulders or the back, although no part of the body is immune. A lipoma may be present over the site of a spina bifida. Subcutaneous lipomas occasionally become pedunculated (lipoma arborescens).
• Sub fascial. Occurring under the palmar or plantar fascia, they are liable to be mistaken for tuberculous tenosynovitis, as the tough, overlying fascia masks the definite edge and lobulation of the tumour. Difficulty is encountered in complete removal as pressure encourages the tumour to ramify. Subfascial lipomas also occur in the areolar layer under the epicranial aponeurosis and, if of long duration, they erode the underlying bone, so that a depression is palpable on pushing the tumour to one side.
• Subs ynovial. From the fatty padding around joints, especially the knee. In the knee, they are apt to be mistaken for Baker’s cysts but are easily distinguished as, in distinction to a cyst or bursa, their consistency is constant whether the joint is in extension or flexion.
• Intenmuscular. Mainly in the thigh or around the shoulder. Owing to transmitted pressure, the tumour becomes firmer when the adjacent muscles are contracted. Weakness or aching results, owing to mechanical interference with muscular action. The condition is often difficult to distinguish from a fibrosarcoma.
• Panosteal occasionally occur under the periosteum of a bone.
• Subserous are sometimes found beneath the pleura, where they constitute one variety of innocent thoracic tumour. A retroperitoneal lipoma may grow to enormous dimensions, and simulate a hydronephrosis or pancreatic cyst.
• Submucous occur under the mucous membrane of the respiratory or alimentary tracts. Rarely a submucous Iipoma in the larynx causes respiratory obstruction. A submucous lipoma can occur in the tongue. One situated in the intestine is likely to cause an intussusception, which may be the first indication of its presence.
• Central nervous system. Lipomas may occur anywhere within the extradural spaces, the spinal cord and brain; they usually arise from the pia mater, within the central subarachnoid spaces (especially the quadrigeminal cisterns); a lipoma of the corpus callosum may be accompanied by calcification on the convex margins.
• Intraglandular. Lipomas have been found occasionally in the pancreas, under the renal capsule and in the breast .
• Retropenitoneal. Large lipomas are seen not infrequently in the retroperitoneal tissues. Some of them turn Out to be liposarcomas.
If a lipoma is causing trouble on account of its site, size, appearance or the presence of pain, removal is indicated.
During operation, any finger-like projections of the tumour into the surrounding tissue should also be removed. Although the tumour is relatively avascular, care is needed to obtain complete haemostasis in the resulting cavity otherwise a haematoma is common, which may be followed by infection and delay in wound healing; drainage is often necessary.
Diffuselipoma occasionally occurs in the subcutaneous tissue of the neck, from which it spreads on to the preauricular region of the face. The tumour is not obviously encapsulated, and gives rise to no trouble, beyond being unsightly.
True neuromas are rare rumours, and occur in connection with the sympathetic system. They comprise the following types:
• Ganglioneuroma, which consist of ganglion cells and nerve fibres. It arises in connection with the sympathetic ganglia, and therefore is found in the retroperitoneal tissue, or in the neck or thorax.
• Neuroblastoina, which is less differentiated than the ganglioneuroma, the cells being of an embryonic type. The tumour somewhat resembles a round-celled sarcoma, and disseminates by the bloodstream. It occurs in infants and young children. It may occasionally undergo spontaneous remission.
• Myelinic neuroma is very rare, being composed only of nerve fibres, as the ganglion cells are absent. They arise in connection with the spinal cord or pia mater.
Neurilemmoma (syn. Schwannoma)
These lobulated and encapsulated tumours arise from the neurilemrnal cells. They are soft and whitish in appearance. They displace the nerve from which they arise and can be removed.
Neurofibroma arise from the connective tissue of the nerve sheath. The following varieties are described.
A single neurofibroma is usually found in the subcutaneous tissue. The ‘painful subcutaneous nodule’ forms a smooth firm swelling which may be moved in a lateral direction, but is otherwise fixed by the nerve from which it arises. Paraesthesia or pain is likely to occur from the pressure of the tumour on the nerve fibres which are spread over its surface. Cystic degeneration or sarcomatous changes occur occasionally.
Neurofibromas may also grow from the sheath of a peripheral nerve or a cranial nerve, e.g. the acoustic tumour . As the nerve fibres are ‘part and parcel’ of the tumour they are difficult to remove without removal of the nerve itself. In major nerves recurrence is a problem, as is malignant (sarcomatous) change.
(syn. von Rechlinghausen’s disease of nerves)
In this inherited (autosomal-dominant) disease, any cranial, spinal or peripheral nerve may be diffusely or modularly thickened . The overgrowth occurs in connection with the endoneurium. Associated pigmentation (cafe au lait) of the skin is common, and sarcomatous changes may occur.
This rare condition usually occurs in connection with branches of the fifth cranial nerve , although it may occur in the extremities . The affected nerves become enormously thickened as a result of myxofibromatous degeneration of the endoneuriurn.
Elephantiasis neuromatosa is a rare variant congenital condition. The skin is coarse, dry and thickened, resembling an elephant’s hide, and the subcutaneous tissues become greatly thickened. If a leg is affected, the patient finds walking increasingly difficult. A famous patient of the London Hospital with this condition (the ‘Elephant Man’) was befriended by his surgeon, Sir Frederick Treves .
Arises from the connective tissue of the nerve sheath after injury to a nerve (lacerations or amputation). These swellings consist of fibrous tissue and coiled nerve fibres.
They are represented in various forms, capillary, cavernous and plexiform being common.
Glomangioma (syn. glomus tumour)
These rumours arise from a cutaneous glomus composed of a tortuous arteriole which communicates directly with a venule, the vessels being surrounded with a network of small nerves. These specialised organs regulate the temperature of the skin, and are found in the limbs, especially the nail beds. The tumour is compressible. The associated pain is out of all proportion to the size of the tumour, which may be only a few millimetres in diameter. The pain is burning in nature and radiates peripherally, and is more often noticeable when the limb is exposed to sudden changes in temperature.
On section the tumour consists of a mixture of blood spaces, nerve tissue and muscle fibres derived from the wall of the arteriole (angiomyoneuroma). Large cuboidal cells are frequently seen (glomal cells). Cutaneous glomus rumours grow very slowly, and do not become malignant. They should be excised.
The term hamartoma is roughly translated from the Greek as a ‘fault’, and its original meaning was ‘missing the mark in spear throwing’. It is a developmental malformation consisting of overgrowth of tissue or tissues proper to the part. The possible range therefore is very wide and the lesions are often multiple. Common lesions that are hamartomas are benign pigmented moles, and the majority of angiomas and neurofibromas. On rare occasions a malignant change occurs in a hamartoma, but for practical purposes the lesion is benign (Peters).
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