Untypical bilateral breast cancer with peritoneal fibrosis on 18F-FDG PET/CT: case report and literature review.

Background: Retroperitoneal fibrosis, a condition of uncertain origin, is rarely linked to 8% of malignant cases, including breast, lung, gastrointestinal, genitourinary, thyroid, and carcinoid. The mechanism leading to peritoneal fibrosis induced by tumors is not well understood, possibly encompassing direct infiltration of neoplastic cells or the initiation of inflammatory responses prompted by cytokines released by tumor cells. We report a case of breast cancer with renal metastasis and retroperitoneal fibrosis detected using 18F-FDG PET/CT, providing help for clinical diagnosis and treatment. Case report: A 49-year-old woman was referred to the hospital with elevated creatinine and oliguria for over a month. Abdominal computer tomography (CT) and magnetic resonance imaging (MRI) showed a retroperitoneal fibrosis-induced acute kidney injury (AKI) was suspected. However, a percutaneous biopsy of the kidney lesion confirmed metastasis from breast cancer. The physical examination revealed inverted nipples and an orange peel appearance on the skin of both breasts. Ultrasonography revealed bilateral hyperplasia (BIRADS 4a) of the mammary glands and bilateral neck and axillary lymphadenopathy. Subsequently, 18F-deoxyglucose positron emission tomography/computer tomography (18F-FDG PET/CT) detected abnormally high uptake (SUVmax) in the bilateral mammary glands and axillary lymph nodes, suggesting bilateral breast cancer. Furthermore, abnormal 18F-FDG uptake was detected in the kidney, suggesting renal metastasis. In addition, abnormal 18F-FDG uptake was observed in the vertebrae, accompanied by an elevation in inhomogeneous bone mineral density, raising suspicion of bone metastases. However, the possibility of myelodysplasia cannot be dismissed, and further investigations will be conducted during close follow-ups. There was significant 18F-FDG uptake in the retroperitoneal position indicating a potential association between retroperitoneal fibrosis and breast cancer. The final pathological diagnosis of the breast tissue confirmed bilateral invasive ductal carcinoma. The patient had been treated with 11 cycles of albumin-bound (nab)-paclitaxel (0.3 mg) and had no significant adverse reaction. Conclusion: In this case, neither the bilateral breast cancer nor the kidney metastatic lesion showed typical nodules or masses, so breast ultrasound, abdominal CT, and MRI did not suggest malignant lesions. PET/CT played an important role in detecting occult metastases and primary lesions, thereby contributing to more accurate staging, monitoring treatment responses, and prediction of prognosis in breast cancer.

A rare case of primary cardiac diffuse large B-cell lymphoma imaged with 18F-FDG PET/CT: a case report and literature review.

Background: One of the exceptionally rare forms of non-Hodgkin's lymphoma (NHL) is primary cardiac lymphoma (PCL). The principal clinical manifestation in patients with PCL involves cardiac symptoms resulting from myocardial infiltration by lymphoma, including arrhythmias, heart failure, and chest pain. 18F-FDG PET/CT serves as a reliable and indispensable imaging modality for assessing clinically staging NHL. Case report: We present a rare case involving a 72-year-old woman diagnosed with primary intracardiac diffuse large B-cell lymphoma. For further staging, the patient underwent 18F-FDG PET/CT, revealing multiple nodular soft tissue density lesions in the heart and pericardium exhibiting increased FDG metabolism (SUVmax = 12.1). The supradiaphragmatic and infradiaphragmatic segments of the inferior vena cava exhibited irregular morphology with localized nodular changes and increased FDG metabolism in the surrounding area (SUVmax = 9.7). Additionally, multiple enlarged lymph nodes were identified in the left axilla, mediastinum, and adjacent to the abdominal aorta, displaying heterogeneous FDG uptake with an SUVmax of 9.3, indicating lymphoma involvement. The above imaging findings suggested that the mass was a PCL. Hence, the patient underwent a combination of chemotherapy and immunotherapy using R-CDOP (rituximab, cyclophosphamide, liposomal doxorubicin, vincristine, and prednisone). Following two courses of treatment within a span of 2 months, there was a partial remission observed in the cardiac lymphoma and the enlarged lymph nodes. Conclusion: The case elucidated in this report contributes to an enhanced understanding of the disease for clinicians, with 18F-FDG PET/CT providing comprehensive insights into the extent of cardiac involvement, as well as the engagement of extracardiac organs and pathologic lymph nodes. The 18F-FDG PET/CT examination not only visually delineates the lesion's location and extent but also serves as a cornerstone for clinical tumor staging, offering valuable support for treatment monitoring and subsequent follow-up.

Chronic Stress-Induced Elevation of Melanin-Concentrating Hormone in the Locus Coeruleus Inhibits Norepinephrine Production and Associated With Depression-Like Behaviors in Rats.

BACKGROUND: Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that projects throughout the central nervous system, including the noradrenergic locus coeruleus (LC). Our previous study suggested that MCH/MCH receptor 1 (MCHR1) in the LC may be involved in the regulation of depression. The present study investigated whether the role of MCH/MCHR1 in the LC in depression-like behaviors is associated with the regulation of norepinephrine. METHOD: Chronic unpredictable stress (CUS) and an acute intra-LC microinjection of MCH induced depression-like behaviors in rats. The MCHR1 antagonist SNAP-94847 was also microinjected in the LC in rats that were suffering CUS or treated with MCH. The sucrose preference, forced swim, and locomotor tests were used for behavioral evaluation. Immunofluorescence staining, enzyme-linked immunosorbent assay, western blot, and high-performance liquid chromatography with electrochemical detection were used to explore the mechanism of MCH/MCHR1 in the regulation of depression-like behaviors. RESULTS: CUS induced an abnormal elevation of MCH levels and downregulated MCHR1 in the LC, which was highly correlated with the formation of depression-like behaviors. SNAP-94847 exerted antidepressant effects in CUS-exposed rats by normalizing tyrosine hydroxylase, dopamine ß hydroxylase, and norepinephrine in the LC. An acute microinjection of MCH induced depression-like behaviors through its action on MCHR1. MCHR1 antagonism in the LC significantly reversed the MCH-induced downregulation of norepinephrine production by normalizing MCHR1-medicated cAMP-PKA signaling. CONCLUSIONS: Our study confirmed that the MCH/MCHR1 system in the LC may be involved in depression-like behaviors by downregulating norepinephrine production. These results improve our understanding of the pathogenesis of depression that is related to the MCH/MCHR1 system in the LC.

Case Report: A rare case of multicentric angiosarcomas of bone mimicking multiple myeloma on 18F-FDG PET/CT.

Background: Angiosarcoma, a rare endothelial-origin tumor, can develop throughout the body, with the head and neck skin being the most commonly affected areas. It can also originate in other sites such as the breast, iliac artery, and visceral organs including the liver, spleen, and kidneys. Angiosarcoma of the bone is remarkably rare, presenting as either unifocal or multifocal bone lesions and often leading to a grim prognosis. Diagnosing bone angiosarcoma poses a significant challenge. 18F-FDG PET/CT serves as a reliable and indispensable imaging modality for evaluating distant metastases and clinically staging angiosarcomas. Case report: A 57-year-old woman presented with a 10-day history of dizziness and headaches. Cranial CT scan revealed bone destruction of the parietal bone, accompanied by soft tissue lesions, protruding into the epidural space. MRI examination demonstrated lesions with slightly elevated signal intensity on T2FLAIR, showing moderate enhancement. Furthermore, multiple foci were observed within the T12, L1-5, and S1-2 vertebrae, as well as in the bilateral iliac bones. For staging, 18F-FDG PET/CT was performed. The MIP PET showed multifocal FDG-avid lesions in the sternum, bilateral clavicles, bilateral scapulae, multiple ribs, and pelvic bones. Heterogeneous FDG uptake was observed in multiple bone lesions, including intracranial (SUVmax = 11.3), right transverse process of the T10 vertebra (SUVmax = 5.8), ilium (SUVmax = 3.3), and pubis (SUVmax = 4.7). The patient underwent surgical resection of the cranial lesion. The pathological diagnosis was made with a highly differentiated angiosarcoma. Conclusion: Angiosarcoma of bone on FDG PET/CT scans is characterized by abnormal FDG uptake along with osteolytic destruction. This case highlights that angiosarcoma of bone can manifest as multicentric FDG uptake, resembling the pattern seen in multiple myeloma. FDG PET/CT can be a useful tool for staging this rare malignant tumor, offering the potential to guide biopsy procedures toward the most metabolically active site. And it should be considered in the differential diagnosis of multiple osteolytic lesions, including metastatic carcinoma, multiple myeloma, and lymphoma of bone.

Multimodality imaging of Xp11.2 translocation/TFE3 gene fusion associated with renal cell carcinoma: a case report.

Background: Xp11.2 translocation/TFE3 gene fusion associated with renal cell carcinoma (Xp11.2 RCC) exhibits unique biological characteristics and is associated with an increased incidence of tumor thrombosis, lymph node metastasis, and advanced disease stages. Multimodality imaging, including US, contrast-enhanced CT, multi-parametric MRI, and 18F-FDG PET/CT plays a crucial role in the preoperative diagnosis and differentiation of renal tumors. Case report: A 15-year-old female presented with lumbar pain worsened, and developed persistent painless hematuria. The CT attenuation values of the scan without contrast, corticomedullary phase, nephrographic phase, and delayed phases were 35 HU, 83 HU, 82 HU, and 75 HU, respectively. The solid component of the mass displayed heterogeneous marked enhancement. Furthermore, MRU indicated that the lesion involved the cortical medulla and infringed on the renal sinus fat. The lesion appeared isosignal in T1WI, slightly low signal in T2WI, and slightly high signal in DWI. The degree of enhancement in the three phases of enhancement scan was lower than that in the renal parenchyma, and hemorrhage and necrosis were observed within the internal part of the lesion. To further clarify the staging, the patient underwent 18F-FDG PET/CT. PET/CT images showed multiple irregular occupancies in the right kidney with unclear borders, showing a heterogeneous increase in 18F-FDG uptake, with SUVmax values ranging from 2.3 to 5.2 in the routine imaging phase (60 min post-injection), compared to SUVmax values ranging from 2.8 to 6.9 in the delayed imaging phase (160 min post-injection). Additionally, multiple enlarged and fused lymph nodes were observed in the medial part of the right kidney and the retroperitoneum, exhibiting a heterogeneous increase in 18F-FDG uptake, with SUVmax values ranging from 4.1 to 8.7 in the routine imaging phase, compared to SUVmax values ranging from 4.4 to 9.1 in the delayed imaging phase. The postoperative pathology, immunohistochemistry, and molecular analysis of histiocytes were consistent with a diagnosis of Xp11.2 RCC. One month after surgery, enhanced-CT examination of the patient revealed lung metastasis, peritoneal metastasis, and multiple lymph node metastases throughout the body, with an overall survival of 16 months. Conclusion: Xp11.2 RCC exhibits unique biological characteristics and is associated with an increased incidence of tumor thrombosis, lymph node metastasis, and advanced disease stages. Long-term follow-up is essential to monitor the likelihood of recurrence and metastasis. 18F-FDG PET/CT examination can comprehensively visualize the lesion's location and extent, providing a basis for clinical tumor staging and aiding in treatment monitoring and follow-up. To address the limitations of FDG, the utilization of specific tracers designed for RCC or tracers that are not excreted via the urinary system would be ideal. Further advancements in molecular imaging technologies and the development of novel tracers hold great promise in advancing the diagnosis and management of RCC, ultimately contributing to better patient outcomes and overall disease management.

Duodenal-type follicular lymphoma in 18F-FDG PET/CT imaging: a case report.

Follicular lymphoma (FL) is a subtype of non-Hodgkin lymphoma (NHL) that is typically characterized by a slow-growing course. Duodenal-type follicular lymphoma (D-FL) was recently reclassified as a distinct variant. This subtype exhibits unique clinical and biological characteristics, which set it apart from other forms of FL. We report a case of a 36-year-old male patient with multiple, small, gray polypoid lesions in the descending duodenum which were detected by esophagogastroduodenoscopy. The pathological diagnosis was low-grade D-FL. 18F-FDG PET/CT was performed for staging and revealed the pancreas and peripheral lymph nodes were involved by FL, with a clinical IV stage. The patient underwent a bone marrow smear cytology, which revealed no bone marrow abnormalities, and excluded bone marrow involvement. He was treated with six cycles of chemotherapy using the R-CHOP regimen and reached complete remission.

Multimodality imaging of an unusual giant cell tumor of thoracic spine with mediastinal invasion: a case report.

Giant cell tumor (GCT) is a benign yet locally aggressive bone neoplasm typically situated in the juxta-articular metaphysis of long bones. Although spinal involvement is rare, it is predominantly reported in the axial skeleton, with the sacrum being the primary location. Conversely, GCTs are notably uncommon in the thoracic spine. In this report, we present computed tomography (CT), magnetic resonance imaging (MRI), and 2-Deoxy-2-[fluorine-18]-fluoro-D-glucose (18F-FDG) positron emission tomography combined with computed tomography (PET/CT) multimodality imaging findings of a 36-year-old woman diagnosed with a GCT of the thoracic spine. CT scans provide a precise evaluation of cortical thinning and penetration. While MRI lacks specific diagnostic indicators for GCT, it remains invaluable for delineating the extent of soft tissue expansion and the tumor's relationship with intraspinal neural elements - critical information for surgical planning. 18F-FDG PET/CT effectively illustrates the lesion's hypermetabolic and locally aggressive characteristics. It is noteworthy that GCT occasionally exhibits metastatic malignant potential, underscoring the value of FDG PET as a pivotal modality for staging, restaging, or assessing therapy response, and for monitoring the efficacy of radiotherapy. Familiarity with the imaging features of GCT is essential for physicians to avoid misinterpretation. This tumor should be considered in the differential diagnosis of spinal tumors, distinguishing it from bone metastases or neurogenic tumors.