Clinicopathological Features and Prognosis of Invasive Micropapillary Carcinoma Compared to Invasive Ductal Carcinoma-NOS: Worse or Better?

OBJECTIVE: To evaluate whether there are differences in invasive micropapillary carcinoma (IMPC) and invasive ductal carcinoma-NOS (IDC-NOS) according to the clinicopathological features and prognosis including molecular subtypes. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Pathology, University of Health Sciences, Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey, from 2003 to 2016. METHODOLOGY: Operated breast cancer cases (58 IMPC + 326 IDC-NOS), with long-term follow-up findings (cases followed up until 2020), were reviewed. The cases, whose other component was only IDC-NOS, were included in the mixed IMPC group. The clinical features, including clinical presentation, treatments, and follow-up information were obtained from the patient clinical database. The IMPC cases included in the study were re-examined, and micropapillary tumour components were confirmed based on the criteria set by the World Health Organisation (WHO). The clinicopathological findings, recurrence, and survival data of both groups were compared. In addition, IDC-NOS was divided into the molecular subgroups and compared with IMPC cases in terms of 5-year overall survival (OS). RESULTS: There was no significant difference between the two groups for the distribution of molecular subtypes. There was a statistically significant difference among the nuclear grade, tumour size, nodal status, lymphovascular, and perineural invasion. In the first 5-year period, the OS rate for IDC-NOS and IMPC was 90.8% and 86.2% (p<0.05). The 5-year OS rate of luminal A, luminal B, HER2, triple negative (TN), and IMPC patients was 97.6%, 91.3%, 90%, 70%, and 86.2%, respectively (p<0.05). The OS rate in patients with TN and IMPC was similar which was found significantly lower than the other groups (luminal A, luminal B, and HER2). The median OS was 51.3 months and 53.9 months for the patients with TN and IMPC, respectively (p<0.001). This difference disappeared in the 10th and 15th years of follow-up. CONCLUSION: The majority of the deaths in IMPC occurred within the first 5 years. The 5-year OS rates were similar in the TN and IMPC patients. The survival pattern of IMPC is parallel with TN, Therefore, clinical, therapeutic, and prognostic evaluation in IMPC can be done like TN. KEY WORDS: Invasive ductal carcinoma, Invasive micropapillary carcinoma, Survival.

How Accurately FNAC Reflects the Breast Papillary Lesions?

Context: Diagnosis of papillary lesions of the breast by fine needle aspiration cytology (FNAC) is problematic. For this reason, it is situated in the indeterminate zone in classification systems. Aims: To ascertain the accuracy of cytological diagnosis of papillary lesions in distinguishing papillary lesions from non-papillary lesions and to determine whether papillomas can be reliably distinguished from malignant papillary lesions by FNAC. Material and Methods: A total of 346 cases with the diagnoses of breast papillary lesions were selected among 5112 breast FNAC procedures performed in our center. One hundred and thirty-nine cases with excised lesions were included in this study, and their corresponding histology was reviewed. Results: Papillary lesion diagnosis was confirmed by histopathology in 103 (74.1%) of 139 patients. Cytology and histopathology results were not found to be compatible in 35 (25.2%) cases. The diagnostic accuracy of distinguishing papillary breast lesions as malignant or benign was assessed statistically. According to the cytology-histology comparison, one case was evaluated as false negative (FN) and twelve cases as false positive (FP). Overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FNAC in distinguishing papillary lesions as benign or malignant were calculated as 87%, 97%, 83%, 72%, and 98%, respectively. Conclusions: The diagnostic accuracy of papillary breast lesions classified by FNAC might be improved by careful evaluation together with cytological, radiological, and clinical findings (triple test). Cell block may allow more accurate evaluation of the papillary lesion and can be applied to immunohistochemical examination. It may also facilitate the differentiation of benign/malignant papillary lesions.