Findings
Full-field digital mammography (FFDM), bilateral CC and MLO view showed extremely dense breast tissue with no obvious abnormality [Figure 1]. Ultrasound (US) of the breast showed non-specific findings with non-circumscribed mixed echogenic area in the region of palpable lump at 12 o’clock, and a lymph node with eccentric cortical thickening in right axilla [Figure 2]. Subsequent US guided right axillary lymph node FNAC showed reactive hyperplasia. She was followed up after 3 months with persistence of her clinical symptom which was stable. This time she was evaluated with contrast enhanced mammography (CEM) which revealed heterogeneous non-mass enhancement in segmental distribution measuring 56 x 60mm in the central portion of right breast [Figure 3]. Pre-operative dynamic post contrast breast MRI showed nodular and clustered ring non-mass enhancement [Figure 4] in the similar distribution as in CEM. No other abnormality was seen in rest of the right breast and contralateral breast. US guided core needle biopsy of the right breast mass and the final histopathology of the mastectomy specimen yielded ductal carcinoma in situ (DCIS), solid type nuclear grade III without invasion [Figure 5]. Sentinel node biopsy was negative for malignancy.
Answer
High grade Ductal carcinoma in situ.
Discussion
Discussion: Ductal carcinoma in situ (DCIS) is proliferation of tumor cells within the terminal ductal lobular unit with preservation of the basement membrane.1 It is a non-obligate precursor of invasive breast cancer which remains the important cause of morbidity and mortality. Understanding various imaging appearances of DCIS is essential for prompt diagnosis and accurate preoperative assessment of extent of the disease. DCIS is mostly detected in the form of microcalcifiations on screening mammography as clinical symptoms are present only in 10-24% of DCIS patients. 1 However 10-20% of DCIS cases manifest with non-calcified lesions which may be occult on mammography, and 82% of the patients with non-calcified DCIS are symptomatic at the time of diagnosis.2 They present with palpable mass or nipple discharge. Mammography may demonstrate focal asymmetry, mass with indistinct margins, architectural distortion or skin thickening. But, the findings may be obscured due to superimposed breast tissue. Hence, additional imaging modalities play an important role in the diagnosis of non-calcified DCIS. US findings of non-calcified DCIS are heterogeneous and overlap with some of the benign entities including fibrocystic change, apocrine metaplasia, papillary duct hyperplasia and adenosis.3 They are appreciated as a vague area of altered echotexture, mass, cluster of cysts or ductal abnormalities. Masses are often non-circumscribed with indistinct or irregular margins, hypoechoic or complex echotxure, parallel in orientation, no posterior acoustic shadowing or enhancement and may have ductal extension. Non-calcified DCIS manifesting as cluster of cysts or complex cystic mass are usually associated with internal vascularity. Ductal changes are seen in the form of ductectasia, intraductal lesion and periductal hypoechogenicity or desmoplasia. However, 7% of non-calcified DCIS are occult on US. MRI has the highest sensitivity to detect and accurately delineate the true extent of non-calcified DCIS.4 Most often they manifest as clumped non-mass enhancement. The newer breast imaging technology, contrast enhanced mammography (CEM) also depicts DCIS as heterogeneous non-mass enhancement. Few studies have evaluated the use of CEM in DCIS, and results were comparable to MRI. 5 CEM could be another low-cost alternative to MRI especially when CE-MRI could not be performed due to certain limitations or contraindications. Most of the time non-calcified DCIS identified on CE-MRI or CEM can be depicted on second-look US correlating in terms of lesion location, depth, size and shape. Thus US-guided core needle biopsy can be performed. If no US correlate is identified for a suspicious area of non-mass enhancement, MRI guided biopsy should be performed. Pathologically, DCIS has been classified based on architectural pattern (solid, cribriform, papillary, micropapillary, and comedo-type) and the presence of necrosis into low, intermediate and high grade. Low grade DCIS is usually not life threatening associated with better prognosis, slow progression and low recurrence rate. High grade DCIS has worse prognosis associated with rapid progression and may harbour foci of invasion. Treatment: 1.Surgery: Breast conservative surgery (lumpectomy) or mastectomy depending on the extent of the lesion. Sentinel lymph node dissection if planning mastectomy. 2.Radiation therapy: Usually after lumpectomy. 3. Hormonal therapy: Tamoxifen or Leterozol (Aromatase inhibitor) as an adjuvant therapy for 5 years to prevent recurrence of DCIS or invasive breast cancer.
Reference
1. Silverstein MJ, Poller DN, Waisman JR, et al. Prognostic classification of breast ductal carcinoma-insitu. Lancet 1995;345(8958):1154–1157. 2. Ikeda DM, Andersson I. Ductal carcinoma in situ: atypical mammographic appearances. Radiology. 1989;172:661-666. 3. Stavros AT. US of ductal carcinoma in situ. In: Silverstein MJ, ed. Ductal carcinoma in situ of the breast. 2nd ed. Philadelphia, Pa: Lippincott, Williams & Wilkins, 2002; 128–169. 4. Kuhl CK, Schrading S, Bieling HB, et al. MRI for diagnosis of pure ductal carcinoma in situ: a prospective observational study. Lancet 2007;370 (9586):485–492. 5. Cheung YC, Juan YH, Lin YC, et al. Dual-energy contrast enhanced spectral mammography: Enhancement analysis on BI-RADS 4 non-mass microcalcifications in Screened Women. PLoS One 2016;11(9):e0162740
