Which solid benign ovarian tumor consists of transitional epithelial cells with characteristic 'coffee-bean' nuclear grooves?

English Explanation The correct answer is Brenner tumor.
A Brenner tumor is an uncommon, typically solid and benign ovarian tumor of surface epithelial origin . Histologically, it consists of nests, masses, or columns of transitional epithelial cells (resembling urothelium) scattered within a dense, compact fibrous stroma of the ovary . A pathognomonic microscopic feature of these transitional cells is their ovoid nuclei with longitudinal grooves, giving them a classic "coffee-bean" nuclei appearance .

Why other options are incorrect:
- Thecoma: This is a solid, estrogen-producing sex cord-stromal tumor that classically occurs in postmenopausal women . On microscopy, it consists of spindle-shaped theca cells with lipid-rich, vacuolated cytoplasm, but lacks transitional cells and coffee-bean nuclear grooves .
- Fibroma: This is the most common benign solid ovarian tumor . It is hormonally inert and classically associated with Meigs' syndrome (triad of benign ovarian fibroma, ascites, and pleural effusion) . It consists of bundles of spindle-shaped fibroblasts and collagen but does not contain transitional epithelial nests .
- Serous cystadenoma: This is the most common benign epithelial ovarian tumor and is cystic rather than solid . It is lined by a single layer of ciliated low columnar epithelium resembling tubal epithelium .

বাংলা ব্যাখ্যা সঠিক উত্তর হলো Brenner tumor।
Brenner tumor হলো একটি বিরল এবং সাধারণত solid ও benign ovarian tumor যা surface epithelium থেকে metaplasia-র মাধ্যমে transitional epithelium (urothelium)-এ রূপান্তরিত হয়ে উৎপত্তি লাভ করে [1-3]। Histologically, এই টিউমারে ovarian fibrous stroma-র মধ্যে transitional epithelial cell-এর nests বা islands (যা Walthard nests নামে পরিচিত) দেখা যায় । এই cell-গুলোর নিউক্লিয়াসে longitudinal groove বা ভাঁজ থাকে, যার কারণে এদের দেখতে অনেকটা কফি বিনের মতো লাগে । একেই "coffee-bean" nuclei বলা হয়, যা Brenner tumor এর অত্যন্ত গুরুত্বপূর্ণ এবং শনাক্তকারী histological বৈশিষ্ট্য ।

অন্যান্য অপশনগুলো ভুল হওয়ার কারণ:
- Thecoma: এটি একটি estrogen-producing, solid sex cord-stromal tumor যা সাধারণত postmenopausal মহিলাদের ক্ষেত্রে দেখা যায় । অণুবীক্ষণ যন্ত্রে এতে lipid-rich cytoplasm যুক্ত spindle-shaped theca cell দেখা যায়, কোনো transitional epithelial cell বা coffee-bean nuclei থাকে না ।
- Fibroma: এটি ডিম্বাশয়ের সবচেয়ে সাধারণ benign solid tumor । এটি hormonally inert এবং এর সাথে Meigs' syndrome (ascites, pleural effusion এবং benign ovarian fibroma এর ট্রায়াড) সম্পর্কিত থাকে । অণুবীক্ষণ যন্ত্রে এতে collagen fibers এবং spindle-shaped fibroblasts দেখা যায় ।
- Serous cystadenoma: এটি ডিম্বাশয়ের সবচেয়ে সাধারণ benign epithelial tumor যা প্রধানত cystic হয়ে থাকে । এটি ciliated low columnar epithelium দ্বারা আবৃত থাকে ।

BCS High Yield Points
- Brenner tumor represents 1-2% of all ovarian tumors and histologically shows transitional epithelium nests in a compact fibrous stroma [1-3].
- The characteristic "coffee-bean" nuclei (grooved or folded nuclei) are also pathognomonic features found in Granulosa cell tumor (which is also characterized by Call-Exner bodies) .
- Fibroma is the most common benign solid tumor of the ovary and is classically associated with Meigs' syndrome [9-11].
- Serous cystadenoma is the most common benign epithelial tumor of the ovary, while Dermoid cyst (mature cystic teratoma) is the most common ovarian tumor in young women .
- Ovarian tumor marker for epithelial ovarian tumors is CA-125, while sex cord-stromal tumors produce inhibin, estrogen, or testosterone .

Source: DC Dutta’s Textbook of Gynecology and Harsh Mohan's Textbook of Pathology