Page 531 - Concise Pathology for Exam Preparation ( PDFDrive )

516 SECTION II Diseases of Organ Systems

- Poorly differentiated tumours: Irregular nests and cords composed of
highly atypical epithelium invading the stroma.
(iv) Pseudomyxoma peritonei
- Seen in 2–5% cases of ovarian mucinous tumours.
- Characterized by massive gelatinous accumulation arranged in a locu-
lated pattern in the peritoneal cavity.
- Large amount of mucin; reaches peritoneal cavity either by dissection
through cyst wall or through a perforation.
- Strips of mature cells with basally arranged regular vacuoles filled with mu-
cous or individual epithelial cells found free floating within gelatinous masses.
(c) Endometrioid ovarian tumours:
• Ten to twenty-five percent of all surface epithelial tumours.
• Thirty percent are bilateral: 15–30% have a concomitant endometrial carcinoma.
• Solid-cystic; may arise as a mass from an endometriotic cyst filled with choco-
late-coloured fluid.
• Lined by tall columnar epithelium with a centrally located nucleus.
(d) Brenner tumour: Derived from coelomic epithelium of ovary; forms the typical
urothelial-like epithelial elements through a metaplastic process.
(i) Benign Brenner: Rare ovarian neoplasm; affect individuals more than 50 years.
Gross morphology:
• Usually an incidental discovery (because of a large frequency of microscopic
lesions).
• Average size is 2–8 cm; may produce compression of surrounding ovarian
tissue.
• Solid, encapsulated, firm and grey-white with a whorled cut surface.
Microscopy:
• Solid-cystic epithelial nests surrounded by a stroma composed of bundles
of tightly packed spindle-shaped cells.
• Epithelial cells are polygonal to squamoid with pale eosinophilic cytoplasm
and oval nucleus showing longitudinal grooving (coffee-bean appearance).
• No mitotic figures or atypia is seen.
• Association of Brenner with other cystic neoplasms, eg, mucinous
cystadenoma and cystic teratoma are well known.
(ii) Borderline malignant Brenner tumour
• Cystic with papillary fronds
• Epithelium resembles noninvasive papillary transitional cell carcinoma of
urinary bladder or grade 3 dysplasia (squamous cell carcinoma in situ)
(iii) Malignant Brenner tumour: Shows frankly malignant histological features
with stromal invasion by epithelial elements. Malignant component may be:
• Transitional cell carcinoma.
• Squamous cell carcinoma
• Undifferentiated carcinoma
(e) Cystadenofibroma: In some serous neoplasms, fibroblastic stromal component is
unduly prominent, appearing as a solid white nodular focus in an otherwise cystic
lesion; may be benign, borderline or malignant.
(f) Clear cell carcinoma (mesonephroid carcinoma):
Gross morphology: Spongy and cystic.
Microscopy:
• Tubular cystic, papillary or sheet-like arrangement of neoplastic epithelium.
• Tumour cells are large with a clear cytoplasm and nuclei projecting into the
lumina (hob nailing).
• Originally thought to originate from mesonephric rests but now definitely
known to arise from surface epithelium.
2. Tumours of germ cell origin
(a) Dysgerminoma:
• Malignant tumour which arises in second to third decades.
• Counterpart of testicular seminoma.
• Associated with gonadal dysgenesis.

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