CHAPTER X CHAPTER 4 - Cancer et environnement

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A B Fig. 4.14 Intratubular germ cell neoplasia (IGCNU). A Spread of malignant germ cells to rete. B Higher magnification discloses cytological features of IGCNU. non-seminomatous germ cell tumours but not seminoma {886}. If both tumour types are present, the expression is even more heterogeneous. Ultrastructure By electron microscopy the IGCNU are very similar to prespermatogenic germ cells in their early stage of differentiation {911,1895,2409}. Differential diagnosis IGCNU has to be distinguished from spermatogenic arrest at spermatogonia stage, which lacks the nuclear features of IGCNU and PLAP reactivity. Giant spermatogonia have a round nucleus with evenly dispersed chromatin and are solitary and widely scattered. Intratubular seminoma distends and completely obliterates the lumina of the involved tubules. Intratubular spermatocytic seminoma shows the 3 characteristic cell types. less frequent loss of parts of chromosome 4 and 13, and gain of 2p {2694}. Prognosis About 50% of cases progress to invasive germ cell tumours in 5 years and about 90% do so in 7 years. These statements are based on retrospective follow-up of infertile men with IGCNU or prospective surveillance of patients with a treated TGCT or IGCNU in the contralateral testis {233,2750}. Rare cases may not progress {345,892,2116,2431}. Tumours of one histological type Seminoma Definition A germ cell tumour of fairly uniform cells, typically with clear or dense glycogen containing cytoplasm, a large regular nucleus, with one or more nucleoli, and well defined cell borders. ICD-O code 9061/3 Epidemiology The increase in the incidence of testicular germ cell tumours in white populations affects seminoma and non-seminomatous neoplasms equally, the rate doubling about every 30 years. In non white populations trends in incidence are not uniform including both an increase (Singapore Chinese, New Zealand Maoris and Japanese) and no increase (US Blacks) {2017,2132}. Clinical features Signs and symptoms The most common mode of presentation is testicular enlargement, which is usually painless. Hydrocele may be present. Genetics The DNA content of IGCNU has been reported to be between hypotriploid and hypopentaploid {567,676,1830,1900}. In fact, the chromosomal constitution of IGCNU, adjacent to an invasive TGCT is highly similar to the invasive tumours, with the absence of gain of 12p being the major difference {1543,2216,2236,2536}. It can therefore be concluded that gain of 12p is not the initiating event in the development of TGCTs, in line with earlier observations {861}. This demonstrates that polyploidization precedes formation of i(12p). These findings support the model that IGCNU in its karyotypic evolution is only one step behind invasive TGCTs {1964}. CGH has shown that IGCNU adjacent to invasive TGCTs have Fig. 4.15 Intratubular germ cell neoplasia (IGCNU) and microinvasion. Note the lymphocytic infiltration. 230 Tumours of the testis and paratesticular tissue
small tumour insufficient to produce a palpable or macroscopic mass or at the edge of a large tumour; intratubular infiltration; pagetoid spread along the rete. Seminoma cells are round or polygonal with a distinct membrane. Cytoplasm is usually clear reflecting the glycogen or lipid content. Less commonly, they have more densely staining cytoplasm. Nuclei contain prominent nucleoli, which may be bar shaped. Mitoses are variable in number. A Fig. 4.16 Seminoma. A Transverse ultrasound image of the testis shows a large, well defined, uniformly hypoechoic mass (white arrow). A small rim of normal, more hyperechoic, parenchyma remains (black arrows). B Longitudinal ultrasound image of the tesits shows lobular, well defnined, hypoechoic mass (arrows). Imaging Seminoma has one of the more sonographically characteristic appearances of the testicular tumours. They are generally well defined and uniformly hypoechoic. Seminomas can be lobulated or multinodular; however, these nodules are most commonly in continuity with one another. Larger tumours can completely replace the normal parenchyma and may be more heterogeneous. Tumour spread Seminoma metastasizes initially via lymphatics to the paraaortic lymph nodes, and afterward to the mediastinal and supraclavicular nodes. Haematogeneous spread occurs later and involves liver, lung, bones and other organs. B uniform cells arranged in sheets or divided into clusters or columns by fine fibrous trabeculae associated with a lymphocytic infiltrate, which may be dense with follicle formation. Plasma cells and eosinophils may also occur on occasion. Less frequently appearances include dense fibrous bands and "cystic" spaces produced by oedema within the tumour. Granulomatous reaction and fibrosis are common and occasionally so extensive that the neoplasm is obscured. Seminomas usually obliterate testicular architecture but other growth patterns include: interstitial invasion (or microinvasion) in a Variants Cribriform, pseudoglandular and tubular variants of seminoma The seminoma cells may be arranged in a nested pseudoglandular/alveolar or “cribriform” pattern with sparse lymphocytes {549}. A tubular pattern may occur, resembling Sertoli cell tumour {2892}. Confirmation of pure seminoma may require demonstration of positive staining for placental alkaline phosphatase (PLAP) and CD117 (C-Kit) with negative staining for inhibin, alpha-fetoprotein (AFP) and CD30. Seminoma with high mitotic rate Seminomas with a greater degree of cellular pleomorphism, higher mitotic activity and a sparsity of stromal lymphocytes have been called atypical seminoma, Macroscopy The affected testis is usually enlarged although a proportion of seminomas occurs in an atrophic gonad. A small hydrocoele may be present but it is unusual for seminoma to spread into the vaginal sac. Veins in the tunica are prominent. Characteristically a seminoma forms a grey, cream or pale pink soft homogeneous lobulated mass with a clear cut edge and may have irregular foci of yellow necrosis. Cyst formation and haemorrhage are uncommon. Nodules separate from the main mass may be seen and occasionally the tumour is composed of numerous macroscopically distinct nodules. Tumour spread into the epididymis and cord is rare. Histopathology Seminomas are typically composed of A B Fig. 4.17 Seminoma. A Typical homogenous whitish seminoma. B Nodular architecture. A B Fig. 4.18 Seminoma. A Seminoma cells with finely granular eosinophilic cytoplasm. B Intratubular typical seminoma. Germ cell tumours 231
Page 1 and 2: CHAPTER 4X Tumours of the of the Te
Page 3 and 4: TNM classification of germ cell tum
Page 5 and 6: Germ cell tumours P.J. Woodward A.
Page 7 and 8: senting symptom: back or abdominal
Page 9 and 10: A B Fig. 4.03 Germ cell tumours gen
Page 11 and 12: process at all {1524}. In addition,
Page 13: A B Fig. 4.12 Comparison of morphol
Page 17 and 18: A B C Fig. 4.22 Seminoma. A Pseudog
Page 19 and 20: A B Fig. 4.27 Spermatocytic seminom
Page 21 and 22: Differential diagnoses Differential
Page 23 and 24: Histologic patterns Microcystic or
Page 25 and 26: A Fig. 4.40 Yolk sac tumour. A Pleo
Page 27 and 28: Teratoma Teratomas are generally we
Page 29 and 30: A B C Fig. 4.49 Teratoma. A Teratom
Page 31 and 32: A B Fig. 4.52 Teratoma with somatic
Page 33 and 34: A B Fig. 4.59 Mixed germ cell tumou
Page 35 and 36: A B C Fig. 4.64 Leydig cell tumour.
Page 37 and 38: A Fig. 4.69 Androgen insensitivity
Page 39 and 40: tinguished from Sertoli cell nodule
Page 41 and 42: ound and have spherical, regularly
Page 43 and 44: Tumours containing both germ cell a
Page 45 and 46: Miscellaneous tumours of the testis
Page 47 and 48: Lymphoma and plasmacytoma of the te
Page 49 and 50: Tumours of collecting ducts and ret
Page 51 and 52: Tumours of paratesticular structure
Page 53 and 54: Epidemiology Nodular mesothelial hy
Page 55 and 56: A B Fig. 4.104 Papillary cystadenom
Page 57 and 58: Fig. 4.109 Desmoplastic small round
Page 59 and 60: Fig. 4.115 Leiomyosarcoma. Coronal,
Page 61 and 62: Secondary tumours C.J. Davis Defini

CHAPTER X CHAPTER 4 - Cancer et environnement

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