Page 723 - Textbook of Pathology, 6th Edition

germ cell tumours are associated with cryptorchidism. The 707
 TABLE 23.1: Classification of Testicular Tumours.
high incidence is attributed to higher temperature to which
I. GERM CELL TUMOURS the undescended testis in the groin or abdomen is exposed.
1. Seminoma Intra-abdominal testis is at greater risk than the inguinal
2. Spermatocytic seminoma testis. There is increased incidence of tumour in the contra-
3. Embryonal carcinoma lateral normally-descended testis. There are no data to
4. Yolk sac tumour (Syn. endodermal sinus tumour, orchio- confirm or deny whether surgical repositioning or
blastoma, infantile type embryonal carcinoma) orchiopexy of a cryptorchid testis alters the incidence of
5. Polyembryoma testicular tumour. However, surgical correction is still helpful
6. Choriocarcinoma since it is easier to detect the tumour in scrotal testis than in
7. Teratomas an abdominal or inguinal testis.
(i) Mature
(ii) Immature 2. Other developmental disorders. Dysgenetic gonads
(iii) With malignant transformation associated with endocrine abnormalities such as androgen
8. Mixed germ cell tumours insensitivity syndrome have higher incidence of
II. SEX CORD-STROMAL TUMOURS development of germ cell tumours.
1. Leydig cell tumour 3. Genetic factors. Genetic factors play a role in the develop-
2. Sertoli cell tumour (Androblastoma) ment of germ cell tumours supported by the observation of
3. Granulosa cell tumour high incidence in first-degree family members, twins and in
4. Mixed forms white male populations while blacks in Africa have a very
III. COMBINED GERM CELL-SEX CORD-STROMAL TUMOURS low incidence. However, no definite pattern of inheritance
Gonadoblastoma has been recognised.
IV. OTHER TUMOURS 4. Other factors. A few less common factors include the
1. Malignant lymphoma (5%) following:
2. Rare tumours i) Orchitis. A history of mumps or other forms of orchitis
may be given by the patient with germ cell tumour. CHAPTER 23
ii) Trauma. Many patients give a history of trauma prior to
CLASSIFICATION the development of the tumour but it is not certain how
trauma initiates the neoplastic process. Instead, possibly it
The most widely accepted classification is the histogenetic brings the patient to attention of the physician.
classification proposed by the World Health Organisation iii) Carcinogens. A number of carcinogens such as use of
(Table 23.1). Based on this, all testicular tumours are divided certain drugs (e.g. LSD, hormonal therapy for sterility,
into 3 groups: germ cell tumours, sex cord-stromal tumours and copper, zinc etc), exposure to radiation and endocrine abnor-
mixed forms. Vast majority of the testicular tumours (95%) malities may play a role in the development of testicular
arise from germ cells or their precursors in the seminiferous tumours.
tubules, while less than 5% originate from sex cord-stromal
components of the testis. From clinical point of view, germ HISTOGENESIS
cell tumours of the testis are categorised into 2 main groups—
seminomatous and non-seminomatous which need to be Pathogenesis of testicular tumours remains controversial
distinguished (Table 23.2). except that vast majority of these tumours originate from
germ cells. Based on current concepts on histogenesis of
ETIOLOGIC FACTORS testicular tumours, following agreements and disagreements The Male Reproductive System and Prostate
have emerged (Fig. 23.4):
Exact etiology of testicular germ cell tumours is unknown,
but the following factors have been implicated: 1. Developmental disorders. Disorders such as cryptor-
chidism, gonadal dysgenesis and androgen insensitivity
1. Cryptorchidism. The probability of a germ cell tumour syndrome are high risk factors for development of testicular
developing in an undescended testis is 30-50 times greater germ cell tumours. These observations point to develop-
than in a normally-descended testis. About 10% of testicular mental defect in gonadogenesis.

  TABLE 23.2: Distinguishing Features of Seminomatous (SGCT) and Non-seminomatous (NSGCT) Germ Cell Tumours of Testis.
Feature SGCT NSGCT
1. Primary tumour Larger, confined to testis for sufficient time; Smaller, at times indistinct;
testicular contour retained testicular contour may be distorted
2. Metastasis Generally to regional lymph nodes Haematogenous spread early
3. Response to radiation Radiosensitive Radioresistant
4. Serum markers hCG; generally low levels hCG, AFP, or both; high levels
5. Prognosis Better Poor