ABSTRAK
Latar belakang. Karsinoma medular sulit dibedakan secara histopatologik dan imunohistokimia dengan karsinoma invasif NST dengan gambaran medular derajat 3, karena beberapa gambaran yang tumpang tindih. Pembedaannya sangat penting terkait perbedaan tatalaksana dan prognosis. Karsinoma invasif NST dengan gambaran medular derajat 3 dianggap varian dari karsinoma invasif NST derajat 3, sehingga dapat mewakilinya. Karsinoma medular menunjukkan indeks apoptosis yang lebih tinggi dibandingkan karsinoma invasif NST derajat 3. Tujuan penelitian ini adalah mengetahui apakah indeks apoptosis dapat digunakan untuk mempertajam diagnosis karsinoma payudara medular secara obyektif menggunakan indeks apoptosis. Bahan dan Cara. Dilakukan penelitian retrospektif observasional analitik secara potong lintang terhadap 20 kasus karsinoma medular dan 20 kasus karsinoma invasif NST derajat 3. Dilakukan penilaian indeks apoptosis dengan metode TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick endlabeling); selanjutnya membandingkan nilai keduanya dan menghitung titik potongnya. Dari titik potong yang didapat, selanjutnya dibandingkan indeks apoptosisnya pada sediaan simulasi core biopsy dan sediaan mastektomi/eksisinya pada kedua kasus. Hasil. Indeks apoptosis (IA) pada karsinoma medular lebih tinggi secara bermakna dibandingkan karsinoma invasif NST derajat 3 ( p 0,001). Berdasarkan kurva ROC, kami mendapatkan titik potong yang optimal pada IA 1.25. Uji kappa terhadap keselarasan sediaan core biopsy dan eksisi/mastektomi mendapatkan hasil 0,3. Kesimpulan. IA dapat digunakan untuk mempertajam diagnosis karsinoma meduler payudara pada sediaan eksisi/mastektomi. Didapatkan titik potong IA: dinyatakan ´medular´ apabila lebih besar/ sama dengan 1,25. IA potensial dapat membantu pada sediaan core biopsy jika >1.25 pada gambaran histopatologik yang memenuhi sebagian kriteria karsinoma medular.

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ABSTRACT
Background. Difficulties are often faced to differentiate between medullary breast carcinoma and invasive carcinoma of no special type with medullary features grade 3, due to morphology and immunohistochemistry overlapping features. It is important to differentiate between them due to differences in the treatment and prognosis . Invasive carcinoma NST with medullary features grade 3 is considered a variant of invasive carcinoma NST grade 3 so it can represent it. Some study showed that apoptotic index in medullary breast carcinoma is higher than invasive carcinoma of no special type grade 3. The aim of this study is to investigate whether apoptotic index can be more definitive in diagnosing medullary breast carcinoma. Patients and methods. This is a retrospective-analytic cross-sectional study using 20 cases of medullary breast carcinoma and 20 cases of invasive carcinoma of no special type grade 3. Apoptotic cell were assessed by TUNEL and the apoptotic index (AI) was calculated. Results. AI in medullary breast carcinoma is significantly higher than invasive carcinoma of no special type grade 3 (p 0,001). The cut off point of AI between medullary carcinoma and invasive carcinoma NST grade 3 is 1.25. Kappa test was done to determine the concordance between core biopsy simulation AI with the related excision/mastectomy and the result is 0,3. Conclusion. The AI can be used to improve diagnostic accuracy of medullary breast carcinoma in excision/mastectomy. The cut off point of the apoptotic index between medullary carcinoma and invasive carcinoma NST grade 3 is 1.25. Only if AI >1.25 can potentially be used to support the diagnosis of medullary carcinoma in core biopsy in case showing some of the medullary carcinoma morphologic criteria.