Intracystic breast carcinoma. An important differential diagnosis in postmenopausal patients presenting with a rapidly growing breast cyst. Management and literature review.

Intracystic breast carcinoma is a rare clinical entity accounting for 0.5-2% of all breast cancers. It represents a distinctive clinical form rather a histological subtype of breast cancer and can either be in situ or invasive tumor. We herein describe a rare case of intracystic breast carcinoma arising from the wall of a cyst in a postmenopausal patient, who presented with a rapidly growing complex breast cyst. Diagnostic evaluation and management of the patient are discussed along with a review of the literature. Complex breast cysts may represent a diagnostic and therapeutic challenge. An underlying malignancy has been reported in 21-31% of the cases. Preoperative diagnosis is challenging. Complex breast cysts with thick wall, thick inner septations, and intracystic solid components should undergo histological evaluation in order to rule out an underlying malignancy. The cytological analysis may be inconclusive. Ultrasound-guided biopsy is the diagnostic modality of choice. The correlation of clinical features, with imaging and histopathological findings is very important for the optimal treatment. In cases of discordance, a complete surgical excision is necessary with careful assessment of the extent of the disease and appropriate treatment.