Breast imaging differential diagnosis
Breast alternatives are described with BI-RADS-style descriptors: shape, margin, internal enhancement and associated calcification. The clue column states what made the alternative less likely.
| Alternative diagnosis | Feature that argues against it | Case |
|---|---|---|
| Abscess | Presents as a tender fluctuant complex fluid collection with surrounding inflamed fat and systemic symptoms rather than a solid spiculated mass. | Male breast cancer, synchronous tumours, bilateral |
| Acute infectious mastitis or breast abscess | Presents with fever, leukocytosis and focal tenderness with a drainable collection, and improves within one to two weeks of antibiotics, whereas inflammatory breast cancer shows no response. | Inflammatory breast cancer |
| Breast adenosis | Presents with clustered punctate calcifications or a diffuse heterogeneous pattern without a discrete stable circumscribed mass, and lacks the biphasic epithelial and myoepithelial proliferation of adenomyoepithelioma. | Adenomyoepithelioma |
| Breast carcinoma | Primary breast carcinoma arises in the glandular tissue rather than within the implant capsule and shows spiculated morphology with washout kinetics, not a circumscribed intracapsular mass. | Silicone-induced breast implant capsule granuloma (SIGBIC) |
| Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) | BIA-ALCL usually presents as a large peri-implant seroma that does not resolve spontaneously and is often associated with capsular contracture, but it lacks the well-circumscribed, progressively enhancing solid intracapsular nodule seen here. | Silicone-induced breast implant capsule granuloma (SIGBIC) |
| Breast metastasis | Presents as multiple bilateral round circumscribed nodules in a patient with a known extramammary primary; the absence of such a history and the unilateral dominant presentation favour a primary breast lymphoma. | Primary breast lymphoma, diffuse large B-cell |
| Breast sarcoma | Is a large heterogeneous mesenchymal mass without an eccentric subareolar location or the epithelial immunohistochemical profile of primary breast carcinoma. | Male breast cancer, synchronous tumours, bilateral |
| Breast tuberculosis | Usually presents as a cold abscess with chronic sinus tracts and caseating granulomas, with acid-fast bacilli or a positive culture or PCR result, and is often accompanied by necrotic axillary nodes with calcification. | Idiopathic granulomatous mastitis |
| Carcinoma (inflammatory or medullary) | Shows a discrete solid mass with suspicious microcalcifications, spiculated margins and axillary adenopathy, and does not resolve with corticosteroid therapy. | Idiopathic granulomatous mastitis |
| Complex cyst with septations | Shows enhancing internal septa and thickened walls with internal vascularity, and lacks the fat-density lucency and lucent-centred calcifications of fat necrosis. | Microcystic calcifications of fat necrosis |
| Diabetic mastopathy | Occurs in insulin-dependent diabetic men as ill-defined, very hypoechoic masses with dense fibrous stroma that show little or no enhancement on MRI. | Infiltrating ductal carcinoma of the right breast |
| Ductal carcinoma in situ | Typically manifests as segmental linear-branching microcalcifications or clumped non-mass enhancement on MRI, rather than a long-standing stable circumscribed solid nodule. | Adenomyoepithelioma |
| Fibroadenoma | Fibroadenoma is a smaller (usually less than 3 cm), well-circumscribed, homogeneous hypoechoic oval mass with a thin capsule, without the rapid growth, necrosis, cystic change or chest wall infiltration seen here. | Malignant phyllodes tumour of the breast |
| Fibroadenoma | A circumscribed oval hypoechoic mass parallel to the skin with uniform internal echoes and no diffusion restriction, unlike the heterogeneous washout enhancement and profound ADC reduction seen here. | Primary breast lymphoma, diffuse large B-cell |
| granulomatosis with polyangiitis | Produces granulomatous inflammation with vasculitis accompanied by upper-airway, pulmonary or renal disease and positive ANCA serology. | Idiopathic granulomatous mastitis |
| Granulomatous mastitis | Shows lobulocentric granulomas on biopsy without malignant cells or dermal lymphatic tumour emboli, and follows a chronic rather than rapidly progressive course. | Inflammatory breast cancer |
| Gynaecomastia | Produces flame-shaped, centrally located retroareolar glandular tissue symmetrical about the nipple, without a spiculated eccentric mass, microcalcifications or axillary adenopathy. | Male breast cancer, synchronous tumours, bilateral |
| Gynaecomastia (nodular type) | Presents as a subareolar, fan-shaped or flame-shaped retroareolar density that is symmetric and shows neither spiculation nor internal vascularity, unlike the eccentric spiculated mass seen here. | Infiltrating ductal carcinoma of the right breast |
| Haematoma | Evolves over time with changing internal echoes and a haemosiderin rim, and in the subacute phase is hyperintense on T1-weighted MRI without a fat-fluid or oil cyst appearance. | Microcystic calcifications of fat necrosis |
| Hamartoma or fibroadenolipoma | Contains a mixture of fat, fibrous and glandular tissue within a pseudocapsule and shows fat-density components on mammography, which are absent here. | Adenomyoepithelioma |
| Intracapsular haematoma | An intracapsular haematoma shows signal intensity that varies with the age of blood and no progressive nodular enhancement, unlike the enhancing solid mass here. | Silicone-induced breast implant capsule granuloma (SIGBIC) |
| Intracystic papillary carcinoma | Presents as a complex cystic lesion with a solid mural nodule that shows internal vascularity, in contrast to the avascular wall calcifications and oil cysts of fat necrosis. | Microcystic calcifications of fat necrosis |
| Invasive carcinoma of no special type | Usually shows spiculated or irregular margins with architectural distortion and possible microcalcification, whereas these lesions are round, circumscribed and non-calcified with very low ADC values favouring lymphoma. | Primary breast lymphoma, diffuse large B-cell |
| Invasive lobular carcinoma | Shows subtle ill-defined enhancement with architectural distortion and is often mammographically occult, unlike the ductal segmental calcification pattern. | Multifocal high-grade DCIS with invasion |
| Late seroma | A late seroma is a simple fluid collection without a solid enhancing component or nodular areas, whereas this lesion contains a solid intracapsular mass. | Silicone-induced breast implant capsule granuloma (SIGBIC) |
| Liposarcoma and other soft-tissue sarcomas | Characteristically contain macroscopic fat or lipomatous components visible on mammography and MRI, which are absent in this lesion. | Infiltrating ductal carcinoma of the right breast |
| Locally advanced breast carcinoma | Invasive carcinoma usually shows spiculated margins with suspicious microcalcifications and skin or nipple changes and does not typically produce the hugely lobulated, cystic-necrotic mass with rapid interval growth seen in a malignant phyllodes tumour. | Malignant phyllodes tumour of the breast |
| Locally advanced non-inflammatory breast carcinoma | Presents as a dominant mass with overlying skin changes but lacks the diffuse erythema and dermal oedema occupying more than one third of the breast that defines inflammatory disease. | Inflammatory breast cancer |
| Mastitis | Produces diffuse skin thickening, oedema and clustered ring enhancement with clinical inflammation rather than ductal non-mass enhancement. | Multifocal high-grade DCIS with invasion |
| Medullary carcinoma | A well-circumscribed soft round mass with a pushing border and prominent lymphoplasmacytic infiltrate, but it does not show the extremely low ADC values produced by tightly packed lymphoma cells. | Primary breast lymphoma, diffuse large B-cell |
| Metastasis to the breast | Usually appears as multiple superficial, round, circumscribed masses without spiculation and without an in-situ component, typically in a patient with a known extramammary malignancy. | Infiltrating ductal carcinoma of the right breast |
| Metastatic disease to the breast | Usually arises from the contralateral breast, melanoma or lymphoma, presents as one or more circumscribed masses, and requires identification of a primary tumour elsewhere. | Male breast cancer, synchronous tumours, bilateral |
| Myofibroblastoma | A benign spindle-cell tumour that is well-circumscribed and oval with smooth margins, showing no spiculation, no posterior shadowing and no internal vascularity. | Infiltrating ductal carcinoma of the right breast |
| Phyllodes tumour | A large circumscribed lobulated mass with cystic spaces and rapid growth, lacking the homogeneous intermediate T2 signal and marked diffusion restriction of this lesion. | Primary breast lymphoma, diffuse large B-cell |
| Primary breast sarcoma | Primary sarcoma also forms a large heterogeneous mass but lacks the epithelial component and leaf-like architecture of a phyllodes tumour, which is confirmed on histology and immunohistochemistry. | Malignant phyllodes tumour of the breast |
| Radiation dermatitis or radiation recall | Is confined to a previously irradiated field, resolves with supportive care, and produces no diffuse breast enlargement or dermal lymphatic involvement. | Inflammatory breast cancer |
| Seroma | Appears as a well-defined unilocular anechoic collection without internal echoes, septa or fat signal, and does not contain calcification on mammography. | Microcystic calcifications of fat necrosis |
The confirmed diagnosis of each case is stated on the case page and is not repeated here. Sorted alphabetically; the order says nothing about probability.