Lymphomas of the Breast - Clinical Tree

Definition and Epidemiology

Malignant lymphoma arises within lymph nodes or develops outside of nodal tissues (extranodal). Primary extranodal presentation of lymphoma occurs in 20% to 30% of cases and involvement of the breast is uncommon. The diagnosis of primary breast lymphomas (PBL) requires fulfillment of three criteria: the lymphomatous infiltrate is closely associated with mammary tissue, an adequate histopathologic evaluation is performed, and systemic or antecedent extramammary lymphoma is excluded, although ipsilateral axillary lymph node involvement is acceptable. Patients with regional lymph node (supraclavicular and internal mammary) and bilateral breast involvement without evidence of distant disease may be included. Secondary breast lymphoma is the presence of systemic lymphoma with concurrent or subsequent involvement of the breast. PBL is rare, comprising ~2% of extranodal lymphomas, ~1% of non-Hodgkin lymphoma (NHL), and 0.5% of breast malignancies. According to Surveillance, Epidemiology, and End Results (SEER) registry data, the incidence of PBL has increased in the United States over the last four decades, from 0.66 per 1 million women in 1975 to 1977 to 2.96 per 1 million women in 2011 to 2013.

Clinical Features

PBL typically presents in middle aged to elderly women, although younger women, including pregnant or lactating women, and, rarely, men can be affected. The median age at diagnosis for NHL PBL is 62 to 67 years, whereas breast implant–associated anaplastic large cell lymphoma (BIA-ALCL) occurs in younger women with a median age at diagnosis of 52 years. In the majority of patients, PBL is detected by palpation of a painless, unilateral breast mass rather than by mammography. Previous studies suggested that the right breast is more frequently involved than the left; however, recent SEER data indicate that unilateral presentation is balanced between the right and left breasts. Approximately 10% of patients have bilateral breast involvement. B symptoms, including fever, weight loss, and night sweats, are uncommon in PBL.

Imaging Studies

Imaging features of PBL are nonspecific and overlap with other breast malignancies and benign processes. Between 10% and 20% of PBL is diagnosed by mammogram, which is less frequently than breast carcinoma. Mammography most commonly shows oval to round high-density masses without architectural distortion in the surrounding tissue, calcifications, or speculated margins. On ultrasound, PBL typically appears as an oval mass with relatively well-circumscribed margins and a hyperechoic pattern, although PBL can have a wide spectrum of appearances on ultrasound. However, no radiographic features are diagnostic and histologic evaluation is required. Fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) is useful to determine tumor avidity and stage, and is used to monitor response to therapy.

Staging

PBLs that are non-Hodgkin B-cell types are staged according to the Lugano classification. The majority of patients present with limited-stage/localized disease involving the breast and without axillary node involvement (stage IE; E designates extranodal). The remaining patients have regional disease at diagnosis with involvement of axillary lymph nodes (stage IIE). Clinical and radiographic assessment of the contralateral breast is mandatory because PBL is bilateral in up to 11% of patients at diagnosis. Bilateral PBL has a worse overall survival and expert opinion is divided in terms of classifying bilateral PBL as IIE or IVE. Pediatric patients with NHL are staged using a four-stage system proposed by Murphy and Hustu. Similar to the Lugano classification report that updated the Ann Arbor staging system for adult NHL, a revised International Pediatric NHL Staging System (IPNHLSS) has been proposed. The pattern of disease spread in BIA-ALCL is more similar to solid tumors than other NHL subtypes and is staged according to a modified tumor, node, metastasis (TNM) system.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here