Page 509 - Concise Pathology for Exam Preparation ( PDFDrive )

494 SECTION II Diseases of Organ Systems

- Cytotrophoblasts: Regular, polygonal cells with distinct cell borders,
clear cytoplasm; single uniform nucleus; grow in cords and masses.
(iii) Embryonal carcinoma
• Common in third decade
• Tumour is composed of markedly pleomorphic cells, arranged in tubules,
acini or sheets.
• Tumour cells have hyperchromatic nuclei with prominent nucleoli.
• Necrosis is prominent.
• Tumour secretes AFP and HCG.
(c) Teratoma
• Tumour composed of differentiated tissue derived from more than one germ cell
layer arranged in a haphazard but organoid pattern in a fibrous or myxoid
stroma.
• More common in infants and children (constitutes 40% of infantile testicular
tumours). Teratoma in a prepubertal child is considered benign, whereas that in
a post-pubertal male is regarded as malignant.
• A large number of these are mixed tumours (most commonly occur in combination
with embryonal carcinoma).
• Elevated HCG or AFP is found in 50% cases.
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Gross morphology: Large tumour, may replace the whole testis.
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Cut surface: Variegated appearance—grey-white with solid and cystic areas; may
show foci of cartilage and bone formation.
Microscopy:
Based on histology, teratomas are classified into three types:
• Mature (differentiated) teratoma
- Composed of a variety of well-differentiated (resembling adult tissue)
structures like cartilage, bone, smooth muscle, intestinal and respiratory
epithelium, mucous glands, thyroid, bronchial, bronchiolar and transi-
tional epithelium, neural tissue and fat.
- The cystic variant with primarily ectodermal differentiation is labelled ‘dermoid
cyst’ and is more common in ovaries than testes.
• Immature teratoma: Characterized by the presence of elements resembling foetal
or embryonal tissue.
• Teratomas with malignant transformation: Clear evidence of a non–germ cell
malignancy arising in the derivatives of one or more germ cell layers; usually
squamous cell carcinoma, adenocarcinoma or a sarcoma.
2. Sex cord-stromal tumours
(a) Sertoli cell tumours
(i) Yellowish, homogenous cut surface
(ii) Histologically, show small cells arranged in trabeculae or cords resembling
immature seminiferous tubules
(iii) Associated with hormonal effects
(b) Leydig cells
(i) Derived from and resemble normal testicular interstitial cells
(ii) Well-defined nodules , 5 cm in diameter
(iii) Characteristic golden brown colour due to intracytoplasmic inclusions called
Reinke’s crystalloids and lipofuscin.

Q. Differentiate between seminomatous and nonseminomatous
germ cell tumours.

Ans. Differences between the seminomatous and nonseminomatous germ cell tumours
are shown in Table 17.1.

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