Sebaceous breast carcinoma

Abstract

Breast sebaceous carcinoma is one of the rarest breast neoplasms, with less than 30 cases reported worldwide. Due to the rarity, the new WHO classification of breast tumors grouped these tumors among the ductal carcinoma. A detailed description of these cases is relevant due to the insufficient knowledge about the prognosis of this neoplasm. We report the clinical, histological, and immunohistochemical characteristics of a case of sebaceous carcinoma of the breast in an 81-year-old woman with a right breast nodule. The tumor was composed of nests of a varying mixture of sebaceous cells with abundant slightly vacuolated cytoplasm, surrounded by smaller oval-to-fusiform cells with eosinophilic cytoplasm without vacuolization. No lymph node metastases were present. The immunohistochemical reactions were positive for GATA3, EMA, CD15, and GCDFP15 (focal staining), and negative for RE, RP, and HER-2. The tumor was classified as triple-negative. Morphologically, the differential diagnoses included skin sebaceous carcinoma, lipid-rich carcinoma, apocrine carcinoma, and glycogen-rich clear cell carcinoma. Most of the previously reported cases were positive for RE and RP, which generally was associated with a better prognosis. However, some cases presented a more aggressive behavior with distant and lymph node metastases.

Invasive Breast Carcinoma With Sebaceous Morphologic Pattern Showing Lymph Node Macrometastasis: A Case Report

“…This pattern is characterized as a breast carcinoma with sebaceous differentiation originating from the mammary gland tissue, with no evidence of derivation from cutaneous adnexa [ 5 ]. The origin of sebaceous cells in breast carcinoma is not fully understood [ 6 ]. There are hypotheses that attempt to explain sebaceous differentiation, including the existence of a ductal reserve cell capable of sebaceous differentiation, as well as the displacement of the embryonic group of epidermal cells into the breast parenchyma [ 6 ].…”

“…The origin of sebaceous cells in breast carcinoma is not fully understood [ 6 ]. There are hypotheses that attempt to explain sebaceous differentiation, including the existence of a ductal reserve cell capable of sebaceous differentiation, as well as the displacement of the embryonic group of epidermal cells into the breast parenchyma [ 6 ]. The morphology of the tumor is thought to result from the malignant transformation of these cells [ 7 , 8 ].…”

“…The differential diagnosis includes lipid-rich carcinoma, glycogen-rich clear cell carcinoma, and skin SC [ 6 ]. The tumor must originate from breast gland parenchyma and lack evidence of primary cutaneous adnexal sebaceous glands [ 5 ].…”

“…However, unlike the sebaceous pattern which shows a compact lobulated solid growth pattern and finely vacuolated cells, lipid-rich carcinomas infiltrate similarly to a regular invasive ductal carcinoma with a watery-clear cytoplasm and less conspicuous vacuolization [ 12 ]. In lipid-rich carcinoma, cytoplasm may stain positive with Sudan III or Oil red in the fresh material [ 6 ]. Most cases are negative for ER and PR, and Her2 positivity is variable in the literature [ 13 ].…”