Nodular sclerosing adenosis of breast: A diagnostic pitfall in fine needle aspiration cytology
A 46-year-old lady complained of awareness of breast mass. The mass was present for around 12 years and she was taking homeopathic medicines on and off for the same. There was history of waxing and waning in the size of the mass. There was a recent increase in the size of the mass and the surgeon referred the patient for a mammogram and FNA. On examination, the lump measured 3.5 cm, which was very firm to hard in consistency and had restricted mobility. The nipple was mildly retracted. No lymph nodes were palpable in the axilla. Mammography of left breast showed a high-density mass in the central region suspicious of malignancy; however, there was no evidence of microcalcifications. The lesion was classified as BI-RADS 4.\nFNAC was performed using a 23-gauge needle and smears were air-dried and stained using May Grünwald-Giemsa method as well as fixed in 95% ethanol and stained with hematoxylin and eosin. Lump was gritty on FNA and yielded particulate material. The smears were highly cellular and showed predominantly three-dimensional cohesive clusters and few scattered cells [Figure and ]. At places, the clusters showed acinar formation []. Occasional clusters of apocrine cells and singly scattered large cells with moderate nuclear pleomorphism and conspicuous nucleolus were also found []. Admixed benign cell clusters, few bipolar cells and hyalinized eosinophilic stroma were found in the background []. Considering the overall picture, a cytological diagnosis of ductal carcinoma was made, and she was advised surgical excision and histopathological examination to rule out invasion. Lumpectomy was performed, and the histopathological examination of the specimen showed a nodular lesion with expanded lobular units which showed extensive adenosis with marked sclerosis of intervening stroma. The proliferating glands were distorted in many areas and showed apocrine metaplasia at places. The lining cells showed moderate nuclear pleomorphism and atypia []. The individual glands were surrounded by myoepithelial cells which were confirmed by immunohistochemistry for smooth muscle actin (SMA) []. There was no evidence of any associated lobular or ductal intraepithelial neoplasia. The surrounding area showed features of fibrocystic disease. There was no evidence of an in situ or invasive malignancy. Based on these features, a diagnosis of nodular sclerosing adenosis was made.