Context: In situ carcinoma in breast can be studied at two levels:
1. different morphologic patterns
2. by utilizing a prognostic grading system like the Van Nuys system. This study would provide information regarding the patterns, classification, prognostic grading, also predict the risk of recurrence after excision and assist in selecting treatment options.

Aims:
• To estimate the cases displaying different architectural patterns of in situ carcinoma in invasive breast cancers.
• Determination of prognostic index (Van Nuys) of in situ carcinoma based on these patterns.

Methods and Material: A Cross sectional study of 40 Modified Radical Mastectomy specimens collected for a period of 18 months in our Tertiary care hospital. For histopathology study, specimens were fixed in 10% formalin, processed, paraffin embedded, sections (3-5 ì thickness) taken, stained with Haematoxylin and Eosin and studied under light microscope. Statistical analysis used: Continuous variables are expressed as mean ±SD whereas categorical variables are expressed as percentages. Data was analysed using SPSS version 20. P value < 0.0 was considered as statistically significant.

Results: All architectural patterns of DCIS either single or mixed were present in the cases of invasive breast carcinoma, with solid [9 (36%) cases]: most common single architectural pattern and Solid and comedo [7 (47%) cases]: the most common mixed architectural pattern. High grade ductal carcinoma in situ was seen in 18 patients (45% of cases), intermediate grade in 17 patients (43%) and low grade was seen in 5 patients (12%). 

Conclusions: The current study provides evidence of the frequency of significant histologic heterogeneity of in situ carcinoma, with at least 2 different architectural patterns of ductal carcinoma in situ commonly present in individual lesions.

Keywords: Ductal Carcinoma; In Situ Component; Histological Grading.