Cytological features of pure micropapillary carcinoma of various organs: A report of eight cases

Micropapillary carcinoma (MPC) is a rare aggressive tumor, which generally accompanies the primary carcinoma of the organ of its origin, while the pure form is extremely uncommon. Angiolymphatic involvement is widespread and a considerable proportion of the cases present with metastases. The current study presents eight pure MPC cases arising from the breast (n=3), urinary bladder (n=3), parotid gland (n=1) and lung (n=1, presenting with pericardial effusion), with the cytological findings. The eight patients included three female and five male cases aged between 48 and 74 years. The most common cytological findings were three-dimensional aggregates, cell clusters with angulated or scalloped borders, single cells with a columnar configuration and eccentric nuclei, and high-grade nuclear features. Histopathological sections showed accompanying in situ ductal carcinoma in the cases of MPC arising in the parotid gland and breast (n=3), and one case in the bladder exhibited only in situ MPC. The average follow-up period was 20 months (range, 6–54 months) and, during this period, three patients succumbed to the disease. At present, four patients are alive with disease and one patient is alive and disease-free. In conclusion, cytology is an important tool for the diagnosis and management of MPC.