Tumours of the testes

The lymphatic drainage of the testes follows the spermatic cord to end in the para-aortic lymph nodes near the origin of the gonadal vessel. Lymphatics from the medial side of the testis may run with the artery to the vas and drain into a node at the bifurcation of the common iliac artery. The contra-lateral para-aortic lymph nodes are sometimes involved by tumour spread but the inguinal lymph nodes are only affected if the scrotal skin is involved.

Malignant

About 99 per cent of testicular neoplasms are malignant, and although they make up only about 1—2 per cent of malignant tumours in men, they are one of the commonest forms of cancer in the young male adult. Maldescent undoubtedly predisposes to malignancy. It is curious that despite the fact that the testis is usually easily palpable, a testicular tumour often escapes detection until after it has metastasised. There is a campaign to encourage men to perform regular testicular self-examination in the hope that tumours will be detected earlier but as yet this has not been as successful as a similar drive to get women to screen their own breasts for lumps.  

 

Tumours of the testis are classified according to the predominant cellular type:

•  seminoma (40 per cent);

•  teratoma (32 per cent);

•  combined seminoma and teratoma (14 per cent);

•  interstitial tumours (1.5 per cent);

•  lymphoma (7 per cent);

•  other tumours (5.5 per cent).

Teratomas tend to occur in a younger age group, the peak incidence being between 20 and 35 while that of seminoma is between 35 and 45. Seminoma is extremely rare before puberty.

Seminoma

Seminoma compresses neighbouring testicular tissue as it grows (Fig. 68.13). The enlarged testis is smooth and firm. The cut surface is homogeneous and pinkish cream in colour. Occasionally fibrous septa give a lobulated appearance. In rapidly growing tumours there may be areas of necrosis of variable consistency.

Histologically, a seminoma is made of slightly oval cells with clear cytoplasm and large rounded nuclei with prominent acidophilic nucleoli. The cells are arranged in sheets separated by a fine fibrous stroma. Derived from seminiferous tubules, the cells resemble spermatocytes. Active infiltration of the tumour with lymphocytes suggests a good host response and a better prognosis.

Seminomas spread via the lymphatics (Fig. 68.14) and metastasis via the bloodstream is uncommon.

Teratoma

Teratoma arises from totipotent cells in the rete testis and often contains a variety of cell types of which one or more predominate. The tumour may be as small as a peanut or as large as a coconut. Even when large, the tumour is moulded by the tunica albuginea so the overall outline of the testis is maintained although the surface may be slightly irregular.

The usual variety is yellowish in colour with cystic spaces containing gelatinous fluid (Fig. 68.15). Nodules of cartilage are often present.

Histology. The Testicular Tumour Panel has classified teratomas as follows:

•  Teratoma differentiated (TD) (uncommon) has no histologically recognisable malignant components but cannot be considered benign because such growth has metastasised. The best known variety is a dermoid cyst which may contain cartilage and muscle as well as glandular elements.

•       Malignant teratoma intermediate, teratocarcinoma (MTI — A and B)

(most common) contains definitely malignant and incompletely differentiated components. There is some mature tissue in type A but not in type B.

•       Malignant teratoma anaplastic (MTA), embryonal carcinoma is composed of anaplastic cells of embryonal origin in parts. Cells presumed to be derived from yolk sac are often responsible for elevated ct-fetoprotein levels. MTA is not always radiosensitive.

•       Malignant teratoma trophoblastic (MTT) (uncommon) contains within other cell types a syncytial cell mass with malignant villous or papillary cytotrophoblast (chroriocarcinoma). It often produces human chorionic gonadotrophin (HCG). Spread by bloodstream and lymphatics is early. It is one of the most malignant tumours known.

Interstitial cell tumours

Interstitial cell tumours arise from Leydig or Sertoli cells. A Leydig cell tumour masculinises; a Sertoli cell tumour feminises.

Prepubertal interstitial cell tumours excrete .androgens which cause sexual precocity and extreme muscular development. Regression of the symptoms after orchidectomy may be incomplete because of hypertrophy of the contralateral testis.

Postpubertal interstitial cell tumours usually arise from Sertoli cells with output of feminizing hormones leading to gynaecomastia, loss of libido and a-spermia. As a rule the tumour is benign and orchidectomy cures.

Clinical features

The patient may not seek advice for several months after first noticing that he has a testicular lump. A sensation of heaviness occurs when the testis is two or three times its normal size but there is pain in only 30 per cent or so. There is a history of trauma to the affected side in over 10 per cent. It is generally conceded that this merely calls attention to the testicular enlargement and in no way initiates the neoplasm.

On examination, the testis is enlarged, smooth, firm and heavy. Later one or more softer protruberances may be palpable. In no other disease is testicular sensation lost so early or so completely but the sign should be elicited with care for fear of disseminating the disease. Ten per cent have a lax secondary hydrocele which does not usually obscure the underlying tumour. The epididymis is normal at first but becomes more difficult to feel as it is flattened or incorporated in the growth. Thickening of the spermatic cord occurs later due to cremasteric hypertrophy and enlargement of the testicular vessels. The vas is never thickened and rectal examination shows the prostate and seminal vesicles to be normal.

Secondary retroperitoneal deposits may be palpable especially just above the umbilicus on the side of the tumour.

There may be hepatic enlargement. Occasionally, an enlarged supraclavicular node is the presenting sign of a testicular tumour (Fig. 68.16). A chest radiograph is most likely to show pulmonary metastases when the primary tumour is a teratoma (Fig. 68.17).

Occasionally, the predominant symptoms are those of metastatic disease. Intra-abdominal disease may cause abdominal or lumbar pain and the mass may be discovered in the epigastrium. Lung metastases are usually silent but they can cause chest pain, dyspnoea and haemoptysis in the later stages of the disease. The primary tumour may not have been noticed by the patient and may indeed be so tiny that it can only be detected by sophisticated ultrasound imaging or operative exploration. Atypical cases may simulate epididymo-orchitis; there may even be a urinary infection. All testicular swellings should be treated with suspicion and failure to respond to antibiotics should raise the possibility of a testicular tumour. Rarely, patients present with severe pain and acute enlargement of the testis due to haernorrhage into a neoplasm. Between 1 and 5 per cent have gynaecomastia (mainly the teratomas).

The hurricane tumour is a ferocious malignancy which kills in a matter of weeks. A few teratomas grow slowly with increasing enlargement of the testis over 2 or 3 years.

Treatment of testicular tumours

Staging is an essential first step in planning treatment.

•  Blood is collected for radioimmunoassay of tumour markers (human chorionic gonadotrophin, alpha-foetoprotein and lactate dehydrogenase. Their level in the blood can be used to monitor the response to treatment.

•  A chest radiograph will show whether there are pulmonary deposits.

•       Orchidectomy is essential to remove the primary tumour and to obtain information about the histological type of the tumour.

•       Computerised tomography and magnetic resonance imaging are the most useful means of detecting intra­abdominal and intrathoracic secondaries and for detecting their response to therapy.

Scrotal exploration and orchidectomy for suspected testicular tumour. The spermatic cord is displayed by dividing the external oblique aponeurosis through a groin incision. A soft clamp is placed across the cord to stop dissemination of malignant cells as the testis is mobilised into the wound. If there is doubt about the diagnosis at this stage, the testis should be bisected along its anterior convexity so that its internal structure can be examined. If there is a tumour or doubts still remain even after frozen section, the cord should be double ligated at the level of the inguinal ring and divided so that the testis can be removed.

Staging of testicular tumours

The stages are:

•  stage 1: testis lesion only — no spread;

•  stage 2: nodes below the diaphragm only;

•  stage 3: nodes above the diaphragm;

•  stage 4: pulmonary or hepatic metastases.

Management by staging and histological diagnosis (after orchidectomy)

Seminomas are radiosensitive and excellent results have been obtained by irradiating stage 1 and stage 2 tumours. More recently, the tumour has been shown to be highly sensitive to cisplatin, which is already being used for patients with metastatic disease. The experts are divided as to whether patients with stage 1 disease should have adjuvant chemotherapy.

Teratomas are less sensitive to radiation. Stage 1 tumours can be managed by watching the level of serum markers and by repeated computerised tomography. Teratomas at stages 2—4 are managed by chemotherapy. Cisplatin, methotrexate, bleomycin and vincristine have been used in combination with great success. There are those who advocate adjuvant chemotherapy for stage 1 teratoma arguing that effective prophylaxis is less troublesome to the patient than prolonged surveillance.

Retroperitoneal lymph node dissection is sometimes needed when retroperitoneal masses remain after chemotherapy   (Fig. 68.18). The tissue removed may contain only necrotic tissue but a proportion of patients has foci of mature teratoma or active malignancy. The operations can be formidable if the tumour is large and retrograde ejaculation is likely unless steps are taken to preserve the sympathetic outflow to the bladder neck.

Prognosis of testicular tumours depends on the histological type and the stage of the growth.

Seminoma. If there are no metastases 95 per cent will be alive 5 years after orchidectomy and radiotherapy or chemotherapy. If there are metastases survival drops to 75 per cent.

Teratoma. More than 85 per cent 5-year survival is achievable in stages 1 and 2 teratoma. In stages 3 and 4, the survival is about 60 per cent and getting better with improvements in chemotherapy.

Testicular tumours in children are usually anaplastic teratomas. They occur before the age of 3 years and are often rapidly fatal.

Tumours of the epididymis may be benign mesothelioma or malignant sarcoma or secondary carcinoma. They are extremely rare but should not be forgotten when the patient presents with a noncystic lump in the epididymis.