Case 1E -

Radial scar

History: This specimen is from a 53 year old woman. What was the most likely mammographic abnormality that prompted this core needle biopsy? Case 1E - Figure 1 Case 1E - Figure 2 Diagnosis: Radial scar Discussion: Radial scar is an uncommon but important lesion and a great deal of controversy has surrounded radial scars in the breast. This lesion is characterized by a combination of epithelial proliferation, stromal fibrosis and sclerosis resulting in a mass-like lesion. Radial scars can clinically, mammographically, and histologically be mistaken for carcinoma. These stellate lesions are usually only a few millimeters in size, but occasionally they are very complex, exceeding 1 cm. Approximately less than 0.5% of core needle biopsies performed yield radial scar. The pathogenesis of radial scars in the breast is still uncertain. However, there is no doubt that both in situ and invasive carcinoma can occur in association with radial scars. Recent studies by Jacobs et al. and Sanders et al. have shown that radial scars are a histologic risk factor for subsequent development of breast carcinoma. Jacobs et al. demonstrated that the presence of radial scars almost doubles the risk of breast cancer and this risk is further increased in women with larger or multiple radial scars. However, radial scars are not in themselves thought to be premalignant. Both the mammographic and histopathologic appearances of a radial scar overlap with tubular carcinoma. Histologically, radial scars have a central sclerotic core composed of fibrosis and elastosis. Entrapped ductules without atypia are easily found within the central core area. The finding of a myoepithelial layer is a clue to the benign nature of this lesion. At the periphery of the radial scar, there is a benign proliferation composed of adenosis, epithelial hyperplasia, cyst formation and micropapillomas. In tubular carcinoma, a stellate configuration can also be found. However, the diagnosis of tubular carcinoma is a microscopic one and is based on the presence of haphazard proliferation of tubules with open lumens that are tear-drop shaped and lined by a single layer of epithelial cells with apical snouts in about one third of cases. The neoplastic ducts in this lesion are distributed in a background of desmoplastic stroma and not much in the way of benign proliferation is seen. Cytologic atypia is minimal and a myoepithelial cell layer is absent. The differential diagnosis includes sclerosing adenosis. At low power magnification, the entire lesion maintains a lobular configuration with a well-defined periphery, unlike that seen in tubular carcinoma. This lobular configuration is very helpful in differentiating this lesion from malignancy. The size and shape of the tubular structures are quite variable. Many times the most sclerosed region is in the center of the lesion with more dilated ductules around the periphery. However, there are cases of irregular sclerosing adenosis where the tubules are haphazardly arranged and appear pseudoinfiltrative. Apocrine metaplasia is occasionally seen involving sclerosing adenosis; these areas often raise concern for carcinoma. The architecture of sclerosing adenosis may not be as apparent, making the diagnosis sometimes quite difficult on core needle biopsy. The double cell lining with myoepithelial cells and lack of atypia can be very helpful to confirm the benign process. Few studies have correlated the findings in an open biopsy when a radial scar is diagnosed on core needle biopsy. Jackman et al. carried out a study to determine the rate of false-negative findings and histologic underestimates in stereotactic biopsy of nonpalpable lesions. Five radial scars diagnosed in core needle biopsy were included in this study. Two of five radial scars demonstrated carcinoma at open biopsy (1 DCIS, 1 invasive carcinoma). Based on this finding, they believe that radial scars should be categorized as high-risk lesions and require excision. Philpotts et al. found no carcinomas at excision of core needle biopsy detected radial scars; however, there was a high rate of atypia at excision (50%), with four of eight lesions showing atypical ductal hyperplasia. Recently, Brenner et al. evaluated the outcome of cases where radial scar was diagnosed by core needle biopsy. One hundred fifty-seven lesions constituted their study group, with 102 having surgical excision and 55 with mammographic surveillance. They found carcinoma in 28% (8/29) of lesions with associated atypia (not included in table below) and 4% (5/128) of lesions without associated atypia. Cawson et al. reported their experience with core needle biopsy in sampling radial scars. Fifty-four lesions diagnosed as radial scar went to open biopsy and 4 were found to reveal DCIS associated with radial scar; however, all four of these lesions were diagnosed as DCIS or atypical ducal hyperplasia on core needle biopsy. This data adds confusion about management of patients diagnosed with radial scar on core needle biopsy since these patients would be referred to open biopsy without the co-existent radial scar. Summary of Surgical Biopsy Findings in Women with Radial Scar at Core Needle Biopsy* Core Biopsy Surgical Excisional Biopsy Benign Atypical DCIS Inv CA 233 184 (79%) 37 (16%) 11 (4.5%) 1 (0.5%) *Jackman (1999), Philpotts (2000), Kirwan (2000), Brenner (2002), Cawson (2003) Still there is insufficient data on this entity to know how to appropriately manage a patient when the diagnosis of radial scar is rendered at core needle biopsy. Many clinicians feel that for this reason, all radial scars should prompt excision. Others believe that if the mammographic abnormality has the appearance of a radial scar, needle localization and open surgical biopsy is a more suitable approach than core needle biopsy. Larger studies with both surgical and mammographic follow up are very much needed to resolve this issue . References: Alleva DQ, Smetherman DH, Garr, GH, Cederbom GJ. Radial scar of the breast: Radiologic pathologic correlation in 22 cases. Radiographics 1999; 19:S27-S35. Brenner RJ, Jackman RJ, Parker SH, Evans WP, Philpotts, L, Deutch BM, Lechner MC, Lehrer D, Sylvan P, Hunt R, Adler SJ, Forcier N. Percutaneous core needle biopsy of radial scars of the breast: When is excision necessary? AJR 2002; 179:1179-1184. When is excision necessary? AJR 2002; 179:1179-1184. Cawson JN, Malara f, Kavanagh A, Hill P, Balasubramanium G, Henderson M. Fourteen-gauge needle core biopsy of mammographically evident radial scars. Is excision necessary? Cancer 2003; 97:345-351. Elvecrog EL, Lechner MC, Nelson MT. 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Sanders ME, Dupont WD, Schuyler PA, Simpson JF, Page DL. Interdependence of radial scar and proliferative disease with respect to invasive breast cancer risk in benign breast biopsies. Modern Pathology 2002; 15:50A.