Objective: To describe policy and prognosis of patients with a cystic mammary lesion caused by an intracystic mammary carcinoma (ICMC).
Design: Retrospective, descriptive.
Method: The study concerned retrospective analysis of 17 patients presenting with intracystic carcinoma of the breast in an educational clinic in the period 1988-2000, who were selected by searching the national pathology database (PALGA). None of the patients was on hormone replacement therapy. In addition a literature search was carried out in the Medline system.
Results: The patients with an intracystic carcinoma of the breast were 10 years older compared to the other breast cancer patients and presented themselves with a palpable mass. Mammography showed a single, well-defined and lobulated mass. Microcalcifications were uncommon. Ultrasound investigation showed a well-defined, inhomogenous and hypoechoic mass. 6 patients had encysted lesions and in 3 a solid, hypoechoic component within the cystic mass was found. Cytology of the cystic fluid is false negative in 36% (5/14). All patients were treated surgically, varying from excisional biopsy to modified radical mastectomy. In 15 patients an intracystic papillary carcinoma (ICPC) was found. 5 patients show a 'pure' ICPC. In the other 10 patients, 5 had an ICPC with a component of DCIS and 5 patients an ICPC with an invasive component. The median follow-up was 84 months (range: 28-165). In 15 patients no evidence of disease was found at follow-up; 2 patients developed local recurrence. The survival was 100%.
Conclusion: Based on the investigation and on the available literature it is concluded that cysts in breasts of postmenopausal women, who do not use hormone replacement therapy, are malignant until proved otherwise. Ultrasound is invaluable in the diagnostic pathway of intracystic carcinoma of the breast. When ICPC is suspected excisional biopsy with sentinel node biopsy is the treatment of choice. The prognosis is good.