Background/Objectives: To develop a DL-based model predicting recurrence risk in HER2-low breast cancer patients and to compare performance of the MRI-alone, clinicopathologic-alone, and combined models. Methods: We analyzed 453 patients with HER2-low breast cancer who underwent surgery and preoperative breast MRI between May 2018 and April 2022. Patients were randomly assigned to either a training cohort (n = 331) or a test cohort (n = 122). Imaging features were extracted from DCE-MRI and ADC maps, with regions of interest manually annotated by radiologists. Clinicopathological features included tumor size, nodal status, histological grade, and hormone receptor status. Three DL prediction models were developed: a CNN-based MRI-alone model, a clinicopathologic-alone model based on a multi-layer perceptron (MLP) and a combined model integrating CNN-extracted MRI features with clinicopathological data via MLP. Model performance was evaluated using AUC, sensitivity, specificity, and F1-score. Results: The MRI-alone model achieved an AUC of 0.69 (95% CI, 0.68–0.69), with a sensitivity of 37.6% (95% CI, 35.7–39.4), specificity of 87.5% (95% CI, 86.9–88.2), and F1-score of 0.34 (95% CI, 0.33–0.35). The clinicopathologic-alone model yielded the highest AUC of 0.92 (95% CI, 0.92–0.92) and sensitivity of 93.6% (95% CI, 93.4–93.8), but showed the lowest specificity (72.3%, 95% CI, 71.8–72.8) and F1-score of 0.50 (95% CI, 0.49–0.50). The combined model demonstrated the most balanced performance, achieving an AUC of 0.90 (95% CI, 0.89–0.91), sensitivity of 80.0% (95% CI, 78.7–81.3), specificity of 83.2% (95% CI: 82.7–83.6), and the highest F1-score of 0.55 (95% CI, 0.54–0.57). Conclusions: The DL-based model combining MRI and clinicopathological features showed superior performance in predicting recurrence in HER2-low breast cancer. This multimodal approach offers a framework for individualized risk assessment and may aid in refining follow-up strategies.

최서윤, et al. J Korean Soc Radiol. 2023 Jul;84(4):879-888. https://doi.org/10.3348/jksr.2022.0106

IgG4-related disease is a rare immune-mediated disease that can involve many organs in the body. The lymph node is also where IgG4-related diseases occur, but its histological structure is different from that of other organs. For this reason, pathologists have difficulty diagnosing IgG4-related lymphadenopathy. If there were specific imaging findings of IgG4-related lymphadenopathy, it would be of great help to pathologists. A 64-year-old male visited our hospital with right ankle pain. On physical examination, the right lower extremity showed severe swelling with wound dehiscence, and infection was suspected. On CT (128-MDCT, Somatom Definition Flash, Siemens Healthcare) taken at the lower extremity, multiple enlarged lymph nodes were incidentally noted in the right inguinal area. On ultrasonography, a “starry night sign” resembling hyperechoic follicles was observed in the enlarged lymph node. A core needle biopsy was performed, and IgG4-related lymphadenopathy was diagnosed. Laboratory examination showed hypergammaglobulinemia with marked elevated serum IgG4, corresponding to IgG4-related disease. Chest and abdominal imaging were evaluated, but there was no extranodal IgG4-related disease. IgG4-related lymphadenopathy showed a very unique ultrasonography imaging finding. The cortex was filled with diffusely scattered hyperechoic foci and some bright foci gathered to form a follicle. This imaging finding may help diagnose IgG4-related lymphadenopathy.

Rationale: Large cell neuroendocrine carcinoma of the breast (LCNECB) is extremely rare, accounting for <0.1% of breast cancers, and has been associated with aggressive clinical behavior. Owing to its rarity, diagnostic and prognostic imaging features remain poorly defined. Patient concerns: A 55-year-old woman was referred for evaluation after an abnormality was detected on screening mammography. She had no personal or family history of breast cancer. Diagnoses: Mammography and ultrasound revealed a left breast mass with irregular margins. Breast magnetic resonance imaging demonstrated rim enhancement, adjacent vessel sign, increased ipsilateral vascularity, and restricted diffusion. Diffusion-weighted imaging showed an apparent diffusion coefficient (ADC) of 0.745 × 10 ⁻³ mm ² /s, with a peritumoral-to-tumoral ADC ratio of 2.79. Histopathology and immunohistochemistry confirmed LCNECB. Interventions: The patient underwent a partial mastectomy and sentinel lymph node biopsy following preoperative imaging evaluation. Outcomes: The tumor measured 3.1 cm, with lymphatic invasion but no nodal metastasis. The patient did not return after surgery and was lost to follow-up; therefore, subsequent clinical outcomes could not be assessed. Lessons: This case highlights the diagnostic potential of breast magnetic resonance imaging in LCNECB, particularly the presence of pronounced hypervascularity and a markedly elevated peritumoral-to-tumoral ADC ratio, which may serve as valuable imaging markers for prognosis and differentiation.

Background: The synchronous occurrence of primary pure squamous cell carcinoma (SCC) and invasive ductal carcinoma (IDC) of the breast is rare. Accurate identification of synchronous primary malignancies is crucial because their prognosis and treatment differ significantly from recurrent diseases. Herein, we present an unusual case highlighting the synchronous development of primary SCC and IDC in the ipsilateral breast. Case Report: A 48-year-old woman presented with a palpable mass in her right breast. Preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) demonstrated an irregularly shaped mass with internal rim enhancement. Surgical resection confirmed IDC of nuclear grade 3 with a high proliferation index (Ki-67: 70%), and the patient underwent adjuvant chemotherapy without radiation. Five months postoperation, a chest computed tomography (CT) revealed a new round-shaped lesion with rim enhancement and relatively circumscribed margins near the previous operation site. Breast ultrasound additionally identified a complex cystic and solid mass with an echogenic rind and increased vascularity. Following total resection, a pure squamous cell carcinoma with prominent keratinization was confirmed. Conclusion: Accurate and early diagnosis of synchronous multiple primary malignancies from recurrence of the primary tumor is critical for improving prognosis by establishing an appropriate treatment and follow-up plan. Recognizing complex cystic and solid masses with relatively circumscribed margins on radiological imaging can assist clinicians in identifying and managing rare cases where IDC and SCC coexist or appear sequentially within a short period.