Fig. 276.—Branchial Carcinoma—subsequently removed by operation.
It is more common in men than in women, and there is often a history of a small swelling having been present for many years, or even since birth. About middle life more active growth begins, the swelling becomes more fixed and is painful, and once it begins to grow, it increases rapidly and within a month or two may reach the size of a child's head. In spite of its size, however, it seldom causes interference with breathing or swallowing, and it has comparatively little effect on the general health. Clinically, the induration and fixation of the tumour suggest its epitheliomatous character, but the absence of a primary growth in the mouth or pharynx excludes its being a metastasis in the lymph glands.
Unless completely removed at an early stage, recurrence inevitably takes place.
Primary carcinoma may also occur in a supernumerary thyreoid, and in the para-thyreoid glands.
We have met with a case of paraffin epithelioma on the neck, and a similar type of epithelioma may be met with in a lupus or a burn of long standing.
The Thymus Gland.—The thymus gland begins to diminish in size towards the end of the second year, and by the time puberty is reached it has entirely disappeared. In some cases, however, the process of involution fails to take place, and the gland may even undergo hyperplasia and exert pressure on the trachea, the great blood vessels, or the left vagus nerve and its recurrent branch. The enlargement of the thymus may be part of a general lymphatic hyperplasia—known as the status lymphaticus.
The pressure effects may be entirely referable to the trachea—thymus stenosis of the trachea—giving rise to progressive dyspnœa accompanied by stridor, with paroxysmal exacerbations during which the child becomes asphyxiated. It is only expiration that is interfered with, as with each inspiratory effort the gland is sucked in towards the mediastinum and so frees the air-passages, while with expiration it rises again, and, becoming jammed in the upper opening of the thorax, exerts pressure on the trachea, and during expiration a soft swelling is sometimes recognisable in the episternal notch. The paroxysms occur at irregular intervals, and any one of them may prove fatal. In some cases the symptoms seem to be associated with pressure on the blood vessels and nerves rather than on the air-passages, and in these there is distension of the veins and a tendency to syncopal attacks.
The only way to afford relief is to expose the gland and withdraw it from behind the sternum by making traction on its capsule. If the breathing is not thereby improved, the capsule should be opened and the gland shelled out.