A case of breast lymphoma diagnosed by IQon spectral computed tomography

Introduction

Patients with breast cancer who require systemic evaluation need to undergo computed tomography (CT) examination. Conventional CT can quickly detect systemic metastases; however, it is easy to miss small metastatic lesions, which in turn can increase radiation to the breast if additional scans are required. IQon spectral CT uses iodine densitometry to properly evaluate tiny metastatic lesions. Additionally, replacing real plain scans with virtual plain scans that are created by removing iodine reduces radiation exposure (1). This study sought to investigate the diagnostic value of IQon spectral CT for patients with breast tumors in a clinical setting.

Case presentation

A 52-year-old woman presented with redness, puffiness, itching, and red spots on both breasts that had persisted for one month. An ultrasound examination showed multiple breast masses on both sides, and multiple swollen lymph nodes in the right axilla.

The thoracic arterial and venous phases were scanned using a IQon spectral CT (Philips Healthcare, Amsterdam, The Netherlands). The patient was scanned in the prone position, with thoracic sponge pads used to fully extend both breasts. The scanning region extended from the thoracic inlet to the lower edge of the costal arch. The scanning parameters were as follows: tube voltage: 120 KVp; pitch: 0.969; collimator width: 64×0.625; and tube speed: 0.5 s/rotation. Iodixanol (1 mL/kg) was injected via the antecubital vein using a high-pressure syringe (German Ulrich, Ulm, Germany), and the injection flow rate was 3.5 mL/s.

The spectral-based image obtained during the scanning process was transferred to the Philips Intellispace Portal (version 10) post-processing workstation, which provided the effective atomic number map, iodine density map, and energy spectrum curve. The effective atomic number map clearly showed multiple abnormally perfused masses in the arterial stage of the breasts bilaterally (Figure 1). The bilateral breasts were markedly enlarged, with thicker skin, non-concave nipples, and heterogeneous fat density. The maximum intensity projection map revealed multiple non-stenotic vasculature shadows in the lesions in the arterial stage (Figure 2). The iodine density figure revealed a small lymph node (around 5 mm in diameter) in the abdomen fat layer, with apparent iodine uptake in the venous stage, The iodine density was 1.27 mg/mL, which was higher than that of other normal lymph nodes, which had an iodine density of 0.8 mg/mL (Figure 3). The slope of the energy spectrum curve of the breast mass in the venous stage was consistent with that of small metastatic lymph nodes (Figure 4). Multiple metastatic lymph nodes were seen in the right supraclavicular fossa, bilateral axillae, right inguinal region, and mesenteric region. There were multiple mildly delayed-enhancing metastatic tumors in the medial part of the left anterior chest wall, the left adnexal area, the vagina, and the perineum.

Figure 1 Effective atomic number map. This map clearly shows the area of bilateral breast slight perfusion abnormality (the Z-effective value was 7.5) as indicated by the white arrows and represented by the green color. Effective atomic number maps can clarify the extent of the mass and the surrounding invasion. CT, computed tomography; Z effective, effective atomic number; Info, information; A, above; F, front; R, right; L, left; P, posterior.

Figure 2 Maximum intensity projection map. Vascular penetration was observed in the mass, with no evidence of vascular invasion. A, above; F, front; R, right; L, left; P, posterior.

Figure 3 Iodine density map. This is a quantitative method for evaluating perfusion according to the distribution of iodine. This map has been shown to be effective in detecting small metastatic lymph nodes. In this case, a small lymph node in the fat layer of the abdominal wall was identified with a diameter of 5 mm and an iodine uptake of 1.27 mg/mL. This lymph node was confirmed to be metastatic by pathology. This lymph node would have been easily missed by conventional CT. CT, computed tomography; Info, information; Ar, area; Av, average; SD, standard deviation; Perim, perimeter; A, above; F, front; R, right; L, left; P, posterior.

Figure 4 The energy spectrum curve suggested that the slope of the metastatic lymph node in Figure 3 was consistent with that of breast lymphoma. This suggests that this metastatic lymph node had homology with breast lymphoma, and was a lymphoma metastatic lymph node. HU, Hounsfield unit; ROI, region of interest; Av, average; SD, standard deviation; A, above; F, front; R, right; L, left; P, posterior.

The immunohistochemistry results of the bilateral mammary gland aspiration biopsy were as follows: CD20 (diffuse +); MUM1 (+); CD3 (−); CD5 (−); CD10 (−); BCL-2 (+); ki-67 positivity rate: 70%; pathological diagnosis: diffuse large B-cell lymphoma (DLBCL) of the breast (non-Germinal center B-cell-like, stage IV). The immunohistochemistry results of the right abdominal lymph node and left axillary lymph node excision biopsy were as follows: CD20 (+); MUM1 (+); C-myc (+); CD3 (−); BCL-2 (+); BCL-6 (−); ki-67 positivity rate: 85%; pathological diagnosis: lymph node: DLBCL (Figure 5). All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Figure 5 Pathological and immunohistochemical images. Pathological image (A; HE, ×200) and immunohistochemistry (B-D; ×200) result was DLBCL. HE, hematoxylin eosin; DLBCL, diffuse large B-cell lymphoma.

Discussion

DLBCL is the most common lymphoma, and it is characterized by its aggressive nature and rapid growth (2). Extranodal lymphomas are most commonly found in the gastrointestinal tract, head and neck, bone, and skin. Breast lymphoma is extremely rare, accounting for only about 0.05% of breast malignancies, and is most common in postmenopausal women (3). Primary breast lymphoma and secondary breast lymphoma are distinguished based on whether or not they begin in the breast. Primary breast lymphoma is defined as having a primary origin in the breast, with or without axillary, supraclavicular and internal mammary region lymph node involvement, with no other lymphoma present. Secondary breast lymphoma is defined as systemic lymphoma with concurrent or secondary breast involvement. It is rarer than primary breast lymphoma (4). Given the patient’s enlarged lymph nodes throughout her body, including the chest wall, diaphragm, female reproductive system, and breast, a diagnosis of secondary breast lymphoma was considered.

It is important to note that breast lymphoma and other breast cancers have very different treatments and prognoses. Thus, the accurate diagnosis and staging of different breast tumors is crucial for determining the appropriate treatment approach and thus improving patient prognosis. The most commonly available imaging technique is magnetic resonance plain scanning and enhancement (5), However, patients with breast tumors who require systemic evaluation and are unable to undergo scanning for an extended period may require CT examination.

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is widely used for the initial staging of DLBCL due to its superior sensitivity and specificity in detecting both nodal and extranodal disease. FDG-PET/CT provides comprehensive information on the metabolic activity and anatomical distribution of lymphoma, which is essential for identifying the extent of disease and guiding therapeutic decisions. This imaging modality also plays a critical role in assessing the treatment response and detecting early relapse (6). However, FDG-PET/CT is expensive and many patients cannot afford it. It also has a lower spatial resolution and higher radiation dose than IQon spectral CT.

IQon spectral CT is capable of not only evaluating the enhancement mode and morphological characteristics of breast lymphoma, but also of using iodine densitometry to evaluate perfusion, and it can be used to discover small metastatic lymph nodes that are easily missed by conventional enhanced CT. Additionally, the energy spectral curve can be employed to determine the source of lymph node metastasis. Virtual plain scans obtained by removing iodine can replace real plain scans, providing the basis for clinical treatment while reducing the scanning time.

The IQon spectral CT features of breast lymphoma are as follows: (I) thicker breast skin without nipple indentation; (II) a breast mass with regular borders, no burrs or calcification; (III) vascular penetration in the mass, and no signs of invasion, such as stenosis and deformation of blood vessels. Tumors have an even and abundant blood supply, which is why lymphoma necrosis is rare (7); (IV) mild delayed enhancement on the enhanced scan of the mass; and (V) an energy spectrum curve indicating multiple enlarged lymph nodes and metastatic foci throughout the body, which is consistent with the slope of the energy spectrum curve of the breast mass.

In clinical practice, the diagnostic value of IQon spectral CT for patients with breast tumors is significantly higher than that of conventional CT, and the scanning time for patients is reduced; thus, it can be recommended for patients with breast neoplasms.

Acknowledgments

Funding: This study was supported by the National Health Commission Key Laboratory Special Project (No. 23GSSYA-2).

Footnote

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-478/coif). The authors report that this study was supported by the National Health Commission Key Laboratory Special (No. 23GSSYA-2). W.M. receives consulting fees from AMCA. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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