Results

The study comprised 63 patients with breast lesions who underwent FNAC and whose respective histopathology reports were available. The age-wise distribution of patients presenting with breast lumps showed that the majority of cases occurred in the younger and middle age groups. The highest proportion was observed in the 15-24 years age group (32%), followed by the 35-44 years age group (27%) and the 25-34 years age group (25%). A comparatively lower percentage was noted in the 45-54 years age group (10%), as shown in Figure 1.

Figure 1: Bar chart showing the percentage distribution of breast lump cases across different age groups.The highest proportion of cases was observed in the 15-24 years age group (32%), followed by the 35-44 years (27%) and 25-34 years (25%) groups. A marked decline in frequency was seen in older age groups, with 10% of cases in the 45-54 years category and only 3% each in the 55-64 and 65-74 years groups.

The prevalence further declined in the older age groups, with only 3% of cases each in the 55-64 years and 65-74 years categories. This pattern indicates that breast lumps were more commonly reported among younger women, emphasizing the need for increased awareness, early clinical evaluation, and screening practices in this population.

The distribution of breast lumps based on laterality revealed that the majority of cases involved the right breast. Out of the total study population, 34 cases were observed in the right breast, followed by 24 cases in the left breast. Bilateral breast lumps were comparatively less common, accounting for only 5 cases, as shown in Figure 2.

Figure 2: Bar chart illustrating the distribution of breast lumps according to laterality.

On recategorizing breast cytology cases according to the International Academy of Cytology (IAC, 2016), Category I (insufficient material), Category II (benign), Category III (atypical), Category IV (suspicious), and Category V (malignant) comprised 3.17%, 84.06%, 4.8%, 3.17%, and 4.8% of cases, respectively, as shown in Figure 3.

Figure 3: Bar chart depicting the percentage distribution of cases across the five IAC Yokohama categories.Category II constituted the vast majority of cases, accounting for 84.06%, while Categories III and V each represented 4.8% of cases. Categories I and IV were the least common, each comprising 3.17% of the total. Overall, the findings demonstrate a marked predominance of Category II lesions, with all other categories contributing only a small proportion to the total distribution.IAC: International Academy of Cytology.

Among these 63 cases, two cases categorized under Category I (insufficient material) were diagnosed as fibroadenoma on histopathology. Out of 53 cases in Category II (benign), 52 cases were reported as fibroadenoma, fibrocystic disease, mastitis, abscess, and benign phyllodes, while one case was reported as malignant. Out of three cases in Category III (atypical), two cases were benign and one case was malignant. Two cases under Category IV (suspicious of malignancy) and three cases under Category V (malignant) were all reported as malignant (invasive ductal carcinoma), as shown in Figure 4.

Figure 4: Bar chart illustrating the distribution of benign and malignant breast lesions across different diagnostic categories.

The ROM varied across the different diagnostic categories. It was 0% in Category I (insufficient), 1.92% in Category II (benign), 33.3% in Category III (atypical), and 100% in both Category IV (suspicious for malignancy) and Category V (malignant), as illustrated in Figure 5.

Figure 5: Risk of malignancy (ROM) associated with each diagnostic category in breast FNAC.Bars represent the percentage ROM for Category I (non-diagnostic/inadequate, 0%), Category II (benign, 1.92%), Category III (atypical, probably benign, 33%), Category IV (suspicious, probably malignant, 100%), and Category V (malignant, 100%).FNAC: Fine-needle aspiration cytology.

Considering histopathological examination as the gold standard for the diagnosis of breast lesions, FNAC showed a sensitivity of 87.5% and a specificity of 96.4%. The PPV and NPV were 77.7% and 98%, respectively, as presented in the Table 1.

Sl. No. | Parameter | Percentage (%)
1 | Sensitivity | 87.50%
2 | Specificity | 96.40%
3 | PPV | 77.70%
4 | NPV | 98%

Figure 6 demonstrates a case of cytology-histopathology discordance. The FNAC smear (Figure 6A) showed features suggestive of fibroadenoma, including cohesive sheets and branching clusters of ductal epithelial cells with uniform nuclei, the presence of myoepithelial cells, and a relatively clean background, leading to a benign cytological interpretation. However, histopathological examination (Figure 6B) revealed invasive breast carcinoma characterized by infiltrating malignant glands, marked cellular atypia, stromal desmoplasia, and loss of normal ductal architecture.

Figure 6: 6A. Photomicrograph of cytology smear (H&E stain, ×10 magnification) showing features of fibroadenoma. Flat sheets of benign ductal epithelial cells with myoepithelial cells and bipolar naked nuclei are seen in a clean background (Category II: benign). 6B. Photomicrograph (H&E stain, ×40 magnification) showing the histological diagnosis of infiltrating ductal carcinoma, not otherwise specified (NOS).Note: The irregular infiltrative glands with malignant epithelial cells exhibiting nuclear pleomorphism, prominent nucleoli, and desmoplastic stromal reaction.

Figure 7 demonstrates the cytological and corresponding histopathological findings in a case categorized as suspicious for malignancy. The FNAC smear (Figure 7A) showed highly cellular smears composed of loosely cohesive and discohesive clusters of atypical ductal epithelial cells. The cells exhibited an increased nuclear-cytoplasmic ratio, nuclear pleomorphism, hyperchromasia, and prominent nucleoli, leading to a cytological diagnosis of Category IV (suspicious for malignancy). Subsequent histopathological examination (Figure 7B) confirmed the diagnosis of invasive breast carcinoma of no special type (NST), characterized by invasive malignant ductal structures with marked cellular atypia and a desmoplastic stromal reaction.

Figure 7: 7A: Photomicrograph of cytology smear (H&E stain, ×10 magnification) showing features suspicious for malignancy (Category IV). Cohesive clusters of atypical epithelial cells with irregular nuclei, prominent nucleoli, and scant cytoplasm are seen in a necrotic background. 7B: Photomicrograph (H&E stain, ×40 magnification) showing the histological diagnosis of infiltrating ductal carcinoma, not otherwise specified (NOS). Tumor cells form angulated glands and single files infiltrating dense desmoplastic stroma with lymphocytic infiltrate.

Figure 8 depicts the cytological and corresponding histopathological findings in a case diagnosed as malignant. The FNAC smear (Figure 8A) showed highly cellular smears composed of markedly atypical ductal epithelial cells arranged in irregular clusters and dispersed singly. The cells exhibited a high nuclear-cytoplasmic ratio, significant nuclear pleomorphism, hyperchromatic nuclei, irregular nuclear membranes, and prominent nucleoli, consistent with a Category V (malignant) diagnosis. Subsequent histopathological examination (Figure 8B) confirmed the diagnosis of invasive breast carcinoma of NST, characterized by infiltrating malignant ductal structures, marked cytological atypia, and stromal desmoplasia. This case highlights the high diagnostic accuracy of FNAC in identifying malignant breast lesions and reinforces its role as a reliable, rapid, and minimally invasive diagnostic tool in the evaluation of breast lumps.

Figure 8: 8A: Photomicrograph of cytology smear (Papanicolaou stain, ×40 magnification) showing features of malignancy (Category V). 3D malignant epithelial clusters with a high nuclear-to-cytoplasmic ratio, coarse chromatin, irregular nuclear membranes, prominent nucleoli, and tumor diathesis are seen. 8B: Photomicrograph (H&E stain, ×40 magnification) showing the histological diagnosis of infiltrating ductal carcinoma, not otherwise specified (NOS). Ill-formed glands and solid nests of atypical cells with marked pleomorphism and brisk mitotic activity are seen within a sclerotic stroma.