Pseudoangiomatous stromal hyperplasia with columnar cell lesions of the breast: 2 interesting case reports

Abstract

Tumorous pseudoangiomatous stromal hyperplasia (PASH) of mammary gland is a rare benign lesion caused by the hyperplasia of breast interstitial myofibroblast. Columnar cell lesions (CCLs) can be observed in close association with PASH-like stroma. There are extremely few reports of PASH with CCLs in the literature to date. In this study, we performed a detailed morphological and immunohistochemical analysis of 2 cases of this rare phenomenon. Two patients, who were 29 and 22 years of age, were referred to our hospital with masses presenting as rapidly enlarging nodules in the left axilla or in the left breast on physical examination, which were suspected to be malignancy or fibroadenomas, respectively. Interestingly, immunohistochemistry showed that both our cases involved young women who were negative for hormone receptors. More remarkably, case 1 showed new foci arising in the axillary region a very short time after mastectomy. The new foci may have been due to recurrence of the excised PASH or the emergence of new PASH from uncertain causes. The etiology and mechanism of the recurrence of PASH is currently unknown.Therefore, complete surgical resection and long-term postoperative follow-up are important.

Keywords

• Pseudoangiomatous stromal hyperplasia
• Columnar cell lesions
• Morphology
• Immunohistochemistry