68Ga-PSMA PET/CT to Distinguish Brain Metastasis of Renal Cell Carcinoma From Radiation Necrosis After Stereotactic Radiosurgery

ABSTRACT

Renal cell carcinoma (RCC) is the most common primary malignancy of the kidney. Approximately 35% of patients of RCC presents with distant metastasis at initial evaluation. CT and MRI are the mainstay imaging modalities. Distinguishing radiation necrosis from tumor progression after stereotactic radiosurgery is challenging. Herein, we present a case of a 43-year-old man with RCC who was treated with stereotactic radiosurgery for brain metastases. We want to emphasize the potential value of 68Ga-PSMA PET/CT imaging in the differential diagnosis and follow-up of tumor progression from radiation necrosis in RCC patients.

18F-FDG PET/CT Findings of Myeloid Sarcoma in the Pancreas

ABSTRACT

Myeloid sarcoma (MS) is a rare neoplasm of leukemic cells that infiltrates an extramedullary soft tissue. MS may present at initial diagnosis of any myeloproliferative disease or relapse after treatment. It is most commonly associated with acute myeloid leukemia. The incidence of pancreatic involvement of MS is very rare. Herein we present FDG PET/CT findings of a rare case of MS involving the pancreas, which was initially misdiagnosed as pancreatic carcinoma.

Porta Hepatic Schwannoma on FDG PET/CT

ABSTRACT

Schwannomas are benign tumors that arise from Schwann cells of neural sheath. They can occur in any part of the body. However, the most common locations are the head, neck, spinal cord, and extremities. Schwannoma in the porta hepatis is extremely rare. Herein, we describe a case of porta hepatic schwannoma in a 36-year-old woman who presented with abdominal pain for a month.

Sacral Insufficiency Fracture on 68Ga-DOTATATE PET/CT

ABSTRACT

68Ga-DOTATATE PET/CT is an important tool for imaging neuroendocrine tumors, including skeletal metastases. However, false-positive results can occur in inflammatory pathologies such as sacral insufficiency fracture. We report the case of a 47-year-old man who was diagnosed with a neuroendocrine tumor of the pancreas. 68Ga-DOTATATE PET/CT showed 68Ga-DOTATATE uptake at the right side of the sacrum. Afterward, MRI made the diagnosis of sacral insufficiency fracture.

Central Nervous System Complications of Erdheim-Chester Disease: FDG PET/CT Findings

ABSTRACT

Erdheim-Chester disease is an uncommon non-Langerhans cell histiocytosis. The diagnosis depends on imaging and histological criteria. The most common presentation is the multiple bone lesions with involvement of at least 1 more organ. We present the FDG PET/CT findings of a 19-year-old man who presented with central nervous system symptoms such as progressive polyuria, polydipsia, gait disturbances, and eye pain and was later diagnosed with Erdheim-Chester disease.

Brown Tumors Secondary to Tertiary Hyperparathyroidism Masquerading as Lytic or Sclerotic Skeletal Metastases on Preoperative/Postoperative 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: A Case Report

Tertiary hyperparathyroidism (TH) is a rare condition that develops from secondary hyperparathyroidism in cases when the secretion becomes autonomous. Brown tumors (BTs) are rare skeletal lesions of hyperparathyroidism that may mimic cancer metastasis. We report a case of a patient who was diagnosed with TH with multiple BTs which mimics osteolytic/osteoblastic metastases that were evaluated with two fluorodeoxyglucose positron emission tomography scans with an interval of 23 months in the preoperative and postoperative period.

Calcified Adrenal Metastasis of High-Grade Osteosarcoma on FDG PET/CT

ABSTRACT

Classic type of high-grade osteosarcoma is the most common type of skeletal malignancy in children and adolescents. Metastasis of osteosarcoma frequently occurs in the lung. Adrenal metastasis of osteosarcoma is extremely rare, with only few reported case in the literature. Herein, we present the case of a 13-year-old boy with adrenal metastasis of high-grade osteosarcoma, which was seen as a solitary calcified hypermetabolic adrenal lesion on FDG PET/CT.

Petrous Apex Cholesterol Granuloma Showing 68Ga-DOTATATE Uptake

ABSTRACT

The importance of 68Ga-DOTATATE PET/CT in the evaluation of neuroendocrine tumors is well established. However, false-positive results can occur due to inflammatory pathologies. We report a 47-year-old man who was diagnosed with a neuroendocrine tumor of the stomach. Initial 68Ga-DOTATATE PET/CT showed intense 68Ga-DOTATATE uptake in the petrous apex. Histopathological confirmation could not be obtained, thus the asymptomatic patient was followed with periodic clinical/radiologic examinations for more than 2.5 years. Therefore, this lesion was diagnosed as a cholesterol granuloma of the temporal bone. These results suggested that an initial wait-and-scan approach is a feasible management strategy for similar presentations.

68Ga-DOTATATE PET/CT Findings of Cervical Esophageal Neuroendocrine Tumor

ABSTRACT

Neuroendocrine tumors (NETs) of the esophagus are extremely rare and aggressive and have a poor prognosis. Because most esophageal cancers occur in the middle and lower parts of the esophagus, cervical esophageal NETs are even rarer. Herein, we present 68Ga-DOTATATE PET/CT findings in a 37-year-old woman who was diagnosed with cervical esophageal NET.

Recurrent Glomus Jugulare Tumor Invading the Cerebellum on 68Ga-DOTATATE PET/CT

ABSTRACT

Glomus tumors are rare, slow-growing extra-adrenal paragangliomas of the head and neck. Treatment and prevention of neurological deficits become more difficult as these tumors aggressively grow in size and infiltrate adjacent anatomical structures. Because glomus tumors are paragangliomas of neuroendocrine origin, 68Ga-DOTATATE PET/CT can be used as imaging method in the diagnosis and follow-up. In this case, we presented a recurrent glomus jugulare tumor that invaded to the cerebellum on 68Ga-DOTATATE PET/CT imaging.

A Rare Case of Pituitary Carcinoma With Bone Metastases: 68Ga-DOTATATE PET/CT Findings

ABSTRACT

Pituitary carcinomas are extremely rare and aggressive tumors that comprise only 0.2% of all pituitary tumors. Because of its rarity, pituitary carcinomas are difficult to diagnose. Conventional imaging methods are inadequate to detect metastatic lesions. Pituitary carcinomas are neuroendocrine tumors and express somatostatin receptors; therefore, 68Ga-DOTATATE PET/CT may be used in the staging of these rare tumors. Herein, we present an exceptional case of pituitary carcinoma with sclerotic skeletal metastases showing 68Ga-DOTATATE uptake.

18F-FDG PET/CT and 99mTc-MDP Bone Scintigraphy Findings of Multifocal Desmoid Fibromatosis

ABSTRACT

Desmoid fibromatosis, also called desmoid tumors, is a group of locally aggressive fibromatous proliferative disorders. They represent less than 3% of all soft tissue sarcoma and are multifocal in approximately 10% of cases. However, there are only a few cases in the literature describing 18F-FDG PET/CT and 99mTc-MDP bone scan features of extra-abdominal desmoid fibromas, and all were solitary bone lesions. Herein, we presented a unique case of multifocal desmoid fibromatosis of bone illustrating the prospective value of 18F-FDG PET/CT and 99mTc-MDP bone scan in the evaluation of desmoid tumors.

Evaluating therapeutic efficacy of extended shelf-life 90 Y glass microspheres in transarterial radioembolization for colorectal cancer: a quantitative FDG PET/CT analysis

OBJECTIVES

There is a lack of sufficient evidence regarding the use of extended shelf-life (ExSL) Yttrium-90 ( 90 Y) glass radiomicrospheres in metastatic colorectal cancer (mCRC) patients. We aimed to investigate the efficacy of ExSL 90 Y glass radiomicrospheres with a personalized treatment approach by analyzing 18 F-FDG PET/CT quantitative parameters [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] separately before and after the treatment.

METHODS

A total of 93 radioembolization sessions involving 77 patients were included. Simplicit 90 Y software was utilized to perform multicompartmental voxel-based dosimetry. Adverse events were recorded using the CTCAE v5.0 criteria. The survival data were recorded in detail.

RESULTS

The overall disease control rate was 84.9%, with a median overall survival (OS) of 12.7 months and median progression-free survival (PFS) of 8.3 months. A statistically significant increase in treatment response rate was observed when there was an increase in absorbed tumor dose for pre-treatment unit MTV ( P  = 0.005) and TLG ( P  = 0.004) values. We didn't observe any additional side effects/vital risks that could be considered clinically significant.

CONCLUSION

Our study has provided evidence on the therapeutic effectiveness and safety in terms of dose-toxicity profile of ExSL 90 Y glass microspheres in a large cohort of mCRC patients. With a personalized treatment approach, the increase in radiation dose absorbed by the tumor has shown a significant contribution to treatment response rate, as indicated by quantitative measurements obtained through 18 F-FDG PET/CT.

Extranodal Mantle Cell Lymphoma Presented as Bilateral Adrenal Masses on 18 F-FDG PET/CT and 68 Ga-DOTATATE PET/CT

ABSTRACT

Mantle cell lymphoma (MCL) is a rare type of B-cell non-Hodgkin lymphoma that commonly presents with constitutional symptoms, lymphadenopathy, and laboratory abnormalities. Although less common, extranodal involvement of MCL may be seen at initial presentation and most commonly occurs in the spleen, liver, bone marrow, and gastrointestinal tract. Adrenal involvement in MCL is extremely rare, and only a few cases have been reported in the literature. Herein, we present 18 F-FDG PET/CT and 68 Ga-DOTATATE PET/CT findings of a unique case of primary extranodal MCL with gastric and adrenal involvement.

Prognostic significance of 18F-FDG PET/CT indices in metastatic renal cell cancer and evaluation of revised IMDC risk model by including 18F-FDG PET-CT parameters

Background

Prognostic markers in metastatic renal cell cancer (mRCC) are still insufficient. Any prognostic model objectively determines disease burden.

Purpose

To investigate the relationship between 18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) parameters and outcomes in mRCC, and to define a revised International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model for the intermediate-risk group.

Material and Methods

A retrospective study of mRCC was conducted. To investigate the prognostic significance of 18F-FDG PET/CT parameters, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) were determined in pre-treatment images. Cutoff values were defined by ROC curve analyses and their association with outcomes was analyzed. Additionally, a TLG-adjusted IMDC model was created by stratifying intermediate-risk group patients according to TLG levels.

Results

The study included 52 patients. The disease control rate (DCR) was 61.5% and median overall survival (OS) was 18 months (95% confidence interval=9.2–25.8). In the univariate analyses, IMDC score, MTV, and TLG were prognostic factors for Disease Control Rate (DCR), and Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS), IMDC score, lactate dehydrogenase (LDH), treatment option, MTV, and TLG were prognostic factors for OS ( P < 0.05 each). In the multivariate analyses, MTV was an independent prognostic factor for DCR, and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. According to the revised-IMDC model, the intermediate-favorable group showed longer OS than the intermediate-unfavorable group.

Conclusion

Pretreatment MTV was independent prognostic factor for DCR and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. Revised-IMDC model could identify patients with a worse prognosis among the IMDC intermediate-risk group.

Solitary Contralateral Adrenal Metastasis of Renal Cell Carcinoma: 68Ga-DOTATATE PET/CT Findings

ABSTRACT

68Ga-DOTATATE PET/CT is an imaging technique used in the diagnosis of neuroendocrine tumors. Since renal cell carcinoma (RCC) expresses the somatostatin receptors, 68Ga-DOTATATE PET/CT could be used in the surveillance of RCC. However, limited cases showing 68Ga-DOTATATE uptake in the metastases of RCC have been reported before. Herein, we report a case of a 55-year-old woman with a history of left nephrectomy for clear cell renal cell carcinoma 2 years before, and referred to 68Ga-DOTATATE PET/CT for the evaluation of adrenal mass. 68Ga-DOTATATE PET/CT showed intense 68Ga-DOTATATE uptake on the adrenal mass. Histopathology of the adrenal mass confirmed the diagnosis of clear cell renal cell carcinoma metastasis.

18F-FDG PET/CT Metabolic Response With Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Treated With Cyclin-Dependent 4/6 Kinase Inhibitors

ABSTRACT

Dysregulation of the cyclin D-CDK4/6-INK4-RB pathway, which leads to uncontrolled cell proliferation, is frequently observed in breast cancer. Recently, 3 CDK4/6 inhibitors have been FDA approved as first-line treatment for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer. Despite promising clinical results, the metabolic response to treatment with these new drugs has not been elaborately demonstrated yet. Herein, we presented a patient with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer who demonstrated a complete metabolic response on 18F-FDG PET/CT to treatment with a CDK4/6 inhibitor (ribociclib).

Primary Adenosquamous Carcinoma of the Liver on FDG PET/CT

ABSTRACT

Primary adenosquamous carcinoma (ASC) of the liver is a rare subtype of intrahepatic cholangiocarcinoma. Hepatic ASC consists of both adenocarcinoma and squamous cell carcinoma components. Because hepatic ASC is extremely rare, only a few cases describing the imaging findings of hepatic ASC were reported before. Herein, we present FDG PET/CT findings of hepatic ASC in a 78-year-old woman who was admitted to hospital with a 4-week history of right upper quadrant pain.

Skin and Subcutaneous Tissue Metastases of the Pulmonary Carcinoid Tumor on 68 Ga-DOTATATE PET/CT

ABSTRACT

Pulmonary carcinoid tumors are a very rare type of neuroendocrine tumor, accounting for only 1% to 2% of all primary lung cancers. Pulmonary carcinoids most commonly metastasize to the mediastinal lymph nodes, liver, and bones. Metastasis of pulmonary carcinoids to the skin and subcutaneous tissue is extremely rare and has been reported in only a small number of cases. We presented 68 Ga-DOTATATE PET/CT findings of an exceptional case of a pulmonary carcinoid tumor with extensive skin, subcutaneous, thyroid, and intramuscular metastases.