(18)F-FDG PET/CT in bilateral primary adrenal T-cell lymphoma

Primary adrenal lymphoma is extremely rare. We report a young patient who presented with non- specific symptoms of fever and abdominal pain. Conventional imaging modalities demonstrated bilateral bulky adrenal masses, and whole-body fluorine-18-fluorodesoxyglucose ((18)F-FDG) positron emission tomography/computed tomography showed intense (18)F-FDG-avid bilateral adrenal masses with no evidence of extra-adrenal spread. A pathological diagnosis of non-Hodgkin lymphoma of peripheral T-cell type was made. The present case indicates that primary adrenal lymphoma should be included in the differential diagnosis of bilateral adrenal masses.     

Adrenal neoplasms

Adenoma, myelolipoma, phaeochromocytoma, metastases, adrenocortical carcinoma, neuroblastoma, and lymphoma account for the majority of adrenal neoplasms that are encountered in clinical practice. A variety of imaging methods are available for evaluating adrenal lesions including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques such as meta-iodobenzylguanidine (MIBG) scintigraphy and positron-emission tomography (PET). Lipid-sensitive imaging techniques such as unenhanced CT and chemical shift MRI enable detection and characterization of lipid-rich adenomas based on an unenhanced CT attenuation of ≤10?HU and signal loss on opposed-phase compared to in-phase T1-weighted images, respectively. In indeterminate cases, an adrenal CT washout study may differentiate adenomas (both lipid-rich and lipid-poor) from other adrenal neoplasms based on an absolute percentage washout of >60% and/or a relative percentage washout of >40%. This is based on the principle that adenomas show rapid contrast washout while most other adrenal neoplasms including malignant tumours show slow contrast washout instead. (18)F-2-fluoro-2-deoxy-d-glucose-PET ((18)FDG-PET) imaging may differentiate benign from malignant adrenal neoplasms by demonstrating high tracer uptake in malignant neoplasms based on the increased glucose utilization and metabolic activity found in most of these malignancies. In this review, the multi-modality imaging appearances of adrenal neoplasms are discussed and illustrated. Key imaging findings that facilitate lesion characterization and differentiation are emphasized. Awareness of these imaging findings is essential for improving diagnostic confidence and for reducing misinterpretation errors.     

Laparoscopic scar: a mimicker of Sister Mary Joseph's nodule on positron emission tomography/CT

Positron emission tomography/CT is an established imaging method in the diagnosis and staging of cancers. (18)F-fluoro-2-deoxy-d-glucose (FDG) is the most commonly used radiotracer in positron emission tomography/CT. It is a tumour viability agent and usually its uptake within a lesion reflects the presence of a viable tumour tissue. However, false-positive FDG uptake is known to occur in benign processes of either inflammatory or infectious aetiology. We describe FDG uptake at the site of laparoscopic scar that mimicked Sister Mary Joseph's nodule in a patient with gastric adenocarcinoma. Here, the knowledge of the patient's history and subtle imaging findings helped in accurate staging of the patient. In this case report, we emphasize the value of the knowledge of the patient history and awareness of different pitfalls of FDG to achieve a correct diagnosis on positron emission tomography/CT.     

Positron emission tomography/computed tomography in the management of Hodgkin's disease and non-Hodgkin's lymphoma

The incidence of Hodgkin's disease (HD) and Non-Hodgkin's lymphoma (NHL) is around 8% of all malignancies. Fortunately, HD and NHL are among the few malignancies that are potentially curable with current existing treatment modalities, even in advanced or recurrent disease. Accurate staging, early therapy monitoring, and posttreatment evaluation of lymphomas are important for optimum management of these patients. We reviewed the imaging findings of patients with histologically proved lymphoma who underwent staging positron emission tomography/computed tomography (PET/CT), early monitoring therapy PET/CT (after 3 cycles of chemotherapy), and posttreatment PET/CT. PET/CT imaging findings are shown. Utility of PET/CT in recognizing false-positive and false-negative cases of CT and PET alone is addressed. Pitfalls and diagnostic difficulties are analyzed. PET/CT is a new imaging technology that improves the evaluation of lymphoma. This review will help the reader to better understand the imaging findings and applications of PET/CT in the management of lymphoma.     

Difficulties in the prospective diagnosis of functional adrenal diseases by CT

The accuracy of prospective diagnosis of functional adrenal disorders by computed tomography (CT) was evaluated in 65 patients strongly suspected of having such disorders. Thirty-seven patients also underwent adrenal venography and selective adrenal venous sampling. Of the 65 patients, 21 had a hyperfunctioning cortical adenoma, 25 had cortical or medullary hyperplasia, and 11 pheochromocytoma, while 10 had no functional adrenal disease. Diagnosis by CT alone was correct in 66%; diagnosis by CT and venous sampling was correct in 89%. Incorrect prospective CT diagnosis resulted most often from a normal appearance of functionally hyperplastic glands (9 cases), nodular hyperplasia simulating a focal adenoma (8 cases), or an incidental nonfunctioning mass (3 cases). This study emphasizes the need to correlate CT findings with biochemical evaluation and the usefulness of venous sampling in selected cases to avoid inappropriate surgery. When CT is interpreted in correlation with complete biochemical analysis, correct diagnosis can usually be made. A small number of cases may still require adrenal venous sampling.     

Difficulties in the prospective diagnosis of functional adrenal diseases by CT

The accuracy of prospective diagnosis of functional adrenal disorders by computed tomography (CT) was evaluated in 65 patients strongly suspected of having such disorders. Thirty-seven patients also underwent adrenal venography and selective adrenal venous sampling. Of the 65 patients, 21 had a hyperfunctioning cortical adenoma, 25 had cortical or medullary hyperplasia, and 11 pheochromocytoma, while 10 had no functional adrenal disease. Diagnosis by CT alone was correct in 66%; diagnosis by CT and venous sampling was correct in 89%. Incorrect prospective CT diagnosis resulted most often from a normal appearance of functionally hyperplastic glands (9 cases), nodular hyperplasia simulating a focal adenoma (8 cases), or an incidental nonfunctioning mass (3 cases). This study emphasizes the need to correlate CT findings with biochemical evaluation and the usefulness of venous sampling in selected cases to avoid inappropriate surgery. When CT is interpreted in correlation with complete biochemical analysis, correct diagnosis can usually be made. A small number of cases may still require adrenal venous sampling.     

Neurolymphomatosis on F-18 FDG PET/CT and MRI Findings: A Case Report

Neurolymphomatosis is a rare manifestation of malignant lymphoma. A 74-year-old man, in complete remission from diffuse large B cell lymphoma, presented with a loss of pain and temperature sensation in the left hemiface and left upper extremity, and motor weakness in the left upper and both lower extremities. Cerebrospinal fluid analysis and brain magnetic resonance imaging (MRI) findings were negative. Combined fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) revealed multiple linear hypermetabolic lesions along the mandibular branch of the left trigeminal nerve, left brachial plexus, right axillary nerve, right suprarenal plexus, right adrenal gland, right femoral nerve, and both sciatic nerves, which corresponded to the patient’s complex neurologic symptoms. C-spine and pelvic MRI revealed diffuse thickening with enhancement in the left brachial plexus and in the proximal portion of the left sciatic nerve, but negative findings for other sites identified by FDG-PET/CT. These findings suggest that FDG-PET/CT can detect peripheral nerve infiltration by malignant lymphoma earlier than MRI. Thus, if a patient with a history of lymphoma presents with neurologic symptoms, FDG-PET/CT should be performed to evaluate neurolymphomatosis.     

Computed tomography and angiography in the evaluation of adrenal diseases

Computed tomography, adrenal venous blood sampling, phlebography and arteriography were compared as diagnostic methods in 50 proven cases of adrenal disease. The diagnostic accuracy was 90 per cent for CT, 100 per cent for adrenal venous sampling, 75 per cent for phlebography and 58 per cent for arteriography. It was necessary in some instances to correlate the findings for more than one modality to reach a correct diagnosis. From an analysis of the different examination methods a sequence in the radiologic evaluation of the pathologic adrenal gland is suggested. CT can be used to advantage as the primary imaging method. However, the other modalities, still play an important role.     

Calcified adrenal masses

We reviewed 106 cases of adrenal masses of all types in all age groups. Thirty-three contained calcium visible on radiographs, sonography, or computed tomography (CT). Neuroblastoma was the most common calcified adrenal mass (10 cases), and occurred only in children. Adrenal cyst (6 cases) was the most common calcified adrenal mass in adults. Other calcified adrenal masses included 5 cortical adenomas, 4 adrenal carcinomas, 3 cases of adrenal hemorrhage, 2 adrenal metastases, 2 pheochromocytomas, and 1 histoplasmoma. Calcification within an adrenal mass is therefore nonspecific. All the adrenal cysts had a characteristic radiographic pattern, showing only peripheral curvilinear calcification. The presence and pattern of calcium in an adrenal mass must be correlated with other imaging features (e.g., size, homogeneity, enhancement pattern, margination) to allow correct differential diagnosis. This can best be done by CT.     

Primary bilateral adrenal lymphoma: 2 case reports

Primary adrenal lymphoma is extremely rare. We describe 2 patients who presented with adrenal insufficiency or fever 'of unknown origin. Conventional imaging studies demonstrated bilateral bulky adrenal masses, and whole-body FDG positron emission tomography- computed tomography showed that the masses were the unique manifestation. Pathological diagnosis was non-Hodgkin lymphoma. The present cases indicated that primary adrenal lymphoma should be included in the differential diagnosis of bilateral adrenal masses.     

Adrenal gland and adrenal mass calcification

With the widespread use of computed tomography (CT), it is not unusual to find calcification within the adrenal glands. There are a variety of adrenal lesions that may calcify, but usually the appearance of the calcification is not specific. However, when the pattern and morphology of the adrenal calcification are combined with the other imaging features and the appropriate clinical history, the correct diagnosis may be suggested.     

原发性肾上腺淋巴瘤合并肝细胞癌全身18F-FDG PET/CT显像1例

笔者报道了1例原发性肾上腺淋巴瘤（PAL）合并肝细胞癌患者全身18F-氟脱氧葡萄糖（FDG） PET/CT 显像,PAL在临床上相对少见,特别是遇到合并其他恶性肿瘤的患者时容易误诊为恶性肿瘤转移。笔者主要分析了PAL合并肝细胞癌全身18F-FDG PET/CT 显像的特点并进行文献复习,为其诊断提供更多参考。     

A black adrenal adenoma difficult to be differentiated from a malignant adrenal tumor by CT,MRI, scintigraphy and FDG PET/CT examinations

Black adrenal adenoma (BAA) is an adrenal adenoma which contains lipofuscin and has a black or brown appearance. Preoperative diagnosis of BAA is difficult because it is diagnosed by pathologic findings. We report a case of an incidentally discovered non-hyperfunctioning BAA in the left adrenal gland of a 58-year-old man. It showed an oval lipid-poor mass, 3 cm × 2 cm in size on computed tomography (CT) and magnetic resonance imaging (MRI), no avid uptake of ¹³¹I-norcholesterol and ¹²³I-meta-iodobenzylguanidine (MIBG) on scintigraphy, and intense avid uptake of ¹⁸F-fluorodeoxyglucose (FDG) on positron emission tomography–CT (PET/CT). FDG PET/CT showed that it was a hypermetabolic lesion, more intense than the activity of the liver, and the maximum standardized uptake value was 5.6 on 1-h early imaging and 8.3 on 2-h delayed imaging, suggesting a malignant tumor. BAA is a clinically rare benign adrenal adenoma, but it should be kept in mind that BAA may exhibit false-positive results for malignancy or inconclusive results for benignity with modern imaging modalities including CT, MRI, adrenal scintigraphy with radiolabelled cholesterol and radiolabelled MIBG, and FDG-PET like this case.     

肾上腺淋巴瘤的CT 表现

目的：分析肾上腺淋巴瘤的C T表现,以熟悉对该病的认识。方法对20例经手术病理或穿刺活检证实的肾上腺淋巴瘤病例进行回顾性分析,男性15例,女性5例,年龄30～80岁,中位年龄65岁。所有病例均行C T 平扫、增强扫描,观察病变的C T表现并与临床和病理对照。结果20例肾上腺淋巴瘤病例中,双侧的18例,单侧的2例;病灶呈椭圆形25个,三角形的12个,肾上腺漫增厚的1个。肿瘤直径4．1～10．7cm ,平均6．3cm。动态增强动脉期轻度强化,门脉期中度强化,其中均匀强化30个病灶,不均均强化8个病灶。结论肾上腺淋巴瘤有特征性的C T表现,C T检查有助于与肾上腺其他肿瘤鉴别。     

Calcified adrenal masses

We reviewed 106 cases of adrenal masses of all types in all age groups. Thirty-three contained calcium visible on radiographs, sonography, or computed tomography (CT). Neuroblastoma was the most common calcified adrenal mass (10 cases), and occurred only in children. Adrenal cyst (6 cases) was the most common calcified adrenal mass in adults. Other calcified adrenal masses included 5 cortical adenomas, 4 adrenal carcinomas, 3 cases of adrenal hemorrhage, 2 adrenal metastases, 2 pheochromocytomas, and 1 histoplasmoma. Calcification within an adrenal mass is therefore nonspecific. All the adrenal cysts had a characteristic radiographic pattern, showing only peripheral curvilinear calcification. The presence and pattern of calcium in an adrenal mass must be correlated with other imaging features (e.g., size, homogeneity, enhancement pattern, margination) to allow correct differential diagnosis. This can best be done by CT.     

A case of diffuse-type primary hepatic lymphoma mimicking diffuse hepatocellular carcinoma

Primary hepatic lymphoma (PHL) is a very rare disease, especially in the diffuse type. We report a case of a middle-aged man with hepatitis C virus infection who developed diffuse-type PHL mimicking diffuse hepatocellular carcinoma (HCC). Contrast-enhanced computed tomography (CT) and magnetic resonance imaging showed diffusely infiltrated hypovascular lesions throughout the liver, but no intrahepatic portal venous thrombus was observed. Diffusion-weighted imaging and ¹⁸F-FDG positron emission tomography/CT, respectively, showed a very low apparent diffusion coefficient value and high FDG uptake. These findings were more suggestive of diffuse-type PHL than diffuse HCC. Liver biopsy examination confirmed a diagnosis of diffuse large B-cell lymphoma. Systemic staging revealed no evidence of nodal or bone marrow involvement, so PHL was diagnosed. The patient was treated with chemotherapy and achieved complete remission. We suggest that a combination of image modalities may enable differentiation of diffuse-type PHL from diffuse HCC.     

Two cases of adrenal hemangioma: CT and MRI findings with pathological correlations

We present two cases of adrenal hemangioma, a rare non-functioning adrenal tumor, and correlate the CT and MR imaging findings with the pathological findings. Peripheral spotty contrast enhancement with centripetal enhancement was noted in one case. This pattern of enhancement is crucial for diagnosing adrenal hemangioma. The other case showed only thin rim enhancement without centripetal enhancement. This finding can be seen in other adrenal tumors, making diagnosis difficult. Marked hyperintensity on T2-weighted images and focal hyperintensity on T1-weighted images that showed focal hemorrhage and calcification were noted. These findings can also be seen in other adrenal tumors and are not pathognomonic of adrenal hemangioma. However, observing the combination of these findings can lead to the correct diagnosis.     

Adrenal gland scintigraphy

There is no question that high-resolution imaging techniques have revolutionized the approach to diagnostic imaging. Computed tomography (CT) and magnetic resonance imaging provide exquisite images of the adrenal glands and offer the best initial imaging approach in the evaluation of patients with suspected adrenal disease. However, an assessment of anatomy is only a portion of the diagnostic effort, which begins with a biochemical evaluation to establish the presence of adrenal gland dysfunction. With a confirmed biochemical diagnosis in hand, a logical and stepwise diagnostic approach can be tailored to a particular patient. Where scintigraphy fits in the evaluation of diseases of the adrenal cortex and medulla in the context of high-resolution imaging and which radiopharmaceuticals should be deployed has changed substantially during the last 2 decades. Adrenal functional imaging has evolved from classic planar scintigraphy to single-photon emission computed tomography (SPECT) and positron emission tomography (PET) using tracers that, by targeting specific metabolic or synthetic processes within the gland, have depicted adrenal pathophysiology. New PET/CT and SPECT/CT technologies integrate anatomic and functional information and redefine the radiotracer principle in the larger context of high resolution anatomic imaging.     

State-of-the-art adrenal imaging.

The adrenal gland is a common site of disease, and detection of adrenal masses has increased with the expanding use of cross-sectional imaging. Radiology is playing a critical role in not only the detection of adrenal abnormalities but in characterizing them as benign or malignant. The purpose of the article is to illustrate and describe the appropriate radiologic work-up for diseases affecting the adrenal gland. The work-up of a suspected hyperfunctioning adrenal mass (pheochromocytoma and aldosteronoma) should start with appropriate biochemical screening tests followed by thin-collimation computed tomography (CT). If results of CT are not diagnostic, magnetic resonance (MR) and nuclear medicine imaging examinations should be performed. CT has become the study of choice to differentiate a benign adenoma from a metastasis in the oncology patient. If the attenuation of the adrenal gland is over 10 HU at nonenhanced CT, contrast material-enhanced CT should be performed and washout calculated. Over 50% washout of contrast material on a 10-minute delayed CT scan is diagnostic of an adenoma. For adrenal lesions that are indeterminate at CT in the oncology patient, chemical shift MR imaging or adrenal biopsy should be performed. Certain features can be used by the radiologist to establish a definitive diagnosis for most adrenal masses (including carcinoma, infections, and hemorrhage) based on imaging findings alone.