Findings of Pulmonary Amyloidosis on Dual Phase FDG PET/CT Imaging

Pulmonary Amyloidoma Imitating Lung Cancer on 18 F-FDG PET/CT

ABSTRACT

Localized pulmonary amyloidosis forming a solitary mass known as "amyloidoma of the lung" is rare. Differentiation from lung cancer can be difficult due to suspicious features on CT and high 18 F-FDG uptake. We present a case of a 77-year-old woman with an incidental lung lesion on abdominal CT. Further evaluation with chest CT and 18 F-FDG PET/CT maintained the suspicion of lung cancer. However, histology revealed amyloidoma without signs of malignancy. Knowledge of imaging similarities between pulmonary amyloidomas and malignancies is important for interpreting 18 F-FDG PET/CT of lung tumors; however, only biopsy can confirm the rare differential diagnosis such as pulmonary amyloidoma.

FDG avid pulmonary amyloid nodule in a patient with metastatic renal cell cancer on 18F-FDG PET/CT

A 60-year-old man with a background of resected clear cell renal cancer and resected colorectal adenocarcinoma presented with a pulmonary mass lesion in the left upper lobe which was avid on 18-F FDG PET/CT. Needle biopsy confirmed metastatic renal cell cancer, which was surgically excised with wedge resection. Follow-up imaging 6 months later demonstrated a second slowly enlarging subcentimeter nodule in the contralateral lung with increasing FDG avidity, suspicious of further small volume oligometastatic disease. Following surgical resection of the second pulmonary lesion, histopathological examination demonstrated nodular pulmonary amyloidosis and no evidence of malignancy.

Isolated Lymph Node Amyloidosis: Response Assessment to Chemotherapy on Serial 18F-FDG PET/CT Scans

Amyloidosis is a disorder resulting from the deposition of fibrillary protein in the extracellular tissue and can be classified into primary, secondary, familial, and senile types. Isolated lymph node amyloidosis without any other organ involvement is very rarely seen in clinical parlance, and diagnosis remains very challenging owing to nonspecific imaging findings. We present a case of 50-year-old man with lymphadenopathy, which was later confirmed to be amyloidosis on biopsy and serum-free light chain assay with efficacious use of F-FDG PET/CT for response assessment to bortezomib, cyclophosphamide, and dexamethasone.

Value of 18F-FDG PET/CT in the detection of occult malignancy in patients with dermatomyositis

Aim

Dermatomyositis (DM) is an inflammatory myopathy in adults that is strongly associated with malignancy. The aim of this study was to evaluate whether whole-body ¹⁸F-FDG PET/CT imaging can offer a standard option searching for underlying malignancy in DM patients.

Methods

Seventy-five patients diagnosed with DM were referred to our department for whole-body ¹⁸F-FDG PET/CT to determine whether the patients suffered from malignant tumor. All PET images were analyzed by two experienced nuclear medicine physicians separately.

Results

According to the ¹⁸F-FDG PET/CT results, 19 patients were suspected to suffer from malignant tumor, then biopsy was performed. Of the 19 patients, 17 patients were confirmed to have malignant tumor. The pathological types were: nasopharyngeal carcinoma, rectal cancer, lung cancer, colon cancer, gastric cancer, gallbladder cancer, kidney cancer, ovarian cancer, breast cancer, lymphoma and vertebral metastatic adenocarcinoma of unknown origin. No malignancy was found for the 56 PET-negative patients during follow-up. For the age between 17 patients with malignancy and 58 patients without malignancy, no significant difference was observed.

Conclusion

¹⁸F-FDG PET/CT may be a sensitive and effective method in determining whether the patients with DM suffered from malignant tumor.

Imaging Findings and Literature Review of (18)F-FDG PET/CT in Primary Systemic AL Amyloidosis

PURPOSE

Although several case reports and case series have described (18)F-FDG PET/CT in amyloidosis, the value of (18)F-FDG PET/CT for diagnosing amyloidosis has not been clarified. We investigated the imaging findings of (18)F-FDG PET/CT in patients with primary systemic AL amyloidosis.

METHODS

Subjects were 15 patients (M:F = 12:3; age, 61.5 ± 7.4 years) with histologically confirmed primary systemic AL amyloidosis who underwent pretreatment (18)F-FDG PET/CT to rule out the possibility of malignancy or for initial workup of alleged cancer. For involved organs, visual and semiquantitative analyses were performed on (18)F-FDG PET/CT images. In total, 22 organs (10 hearts, 5 kidneys, 2 stomachs, 2 colons, 1 ileum, 1 pancreas, and 1 liver) were histologically confirmed to have primary systemic AL amyloidosis.

RESULTS

F-FDG uptake was significantly increased in 15 of the 22 organs (68.2 %; 10 hearts, 2 kidneys, 1 colon, 1 ileum, and 1 liver; SUVmax = 7.0 ± 3.2, range 2.1-14.1). However, in 11 of 15 PET-positive organs (78.6 %; 10 hearts and the ileum), it was difficult to differentiate pathological uptake from physiological uptake. Definitely abnormal (18)F-FDG uptake was found in only 4 of the 22 organs (18.2 %; 2 kidneys, 1 colon, and the liver). (18)F-FDG uptake was negative for pancreas and gastric lesions.

CONCLUSIONS

Although (18)F-FDG PET/CT showed high uptake in two-thirds of the organs involving primary systemic AL amyloidosis, its sensitivity appeared to be low to make differentiation of pathological uptake from physiological uptake. However, due to the small number of cases, further study for the role of (18)F-FDG PET/CT in amyloidosis will be warranted.

Primary pulmonary amyloidosis misdiagnosed as malignancy on dual-time-point fluoro-deoxyglucose positron emission tomography/computed tomography: A case report and review of the literature

Primary pulmonary amyloidosis is an uncommon manifestation, characterized by amyloid deposition in the lungs and other associated tissue. The clinical presentation of amyloidosis is variable, with non-specific symptoms. The current study reports the case of a 59-year-old female presenting with primary pulmonary amyloidosis, indistinguishable from lung malignancy based on 18F-fluoro-deoxyglucose (18F-FDG) accumulation on dual-time-point (DTP) FDG-positron emission tomography/computed tomography (PET/CT) imaging and the similarities in morphological changes. A percutaneous CT-guided thoracoscopic biopsy was subsequently performed. Histological examination revealed that the specimens contained amorphous, homogeneous material with a number of polyclonal plasma cells, lymphocytes and giant cells. A diagnosis of primary nodular parenchymal pulmonary amyloidosis was determined, and the patient was discharged without chemotherapy. The patient remained in good clinical condition during follow-up. The present case indicated that localized nodular amyloidosis with increased FDG uptake on DTP FDG PET must be considered in the differential diagnosis of growing lung nodules, and that a histological examination must be conducted to distinguish this condition from malignancies of the lung.

(18)F-FDG PET/CT in Patients with Nodular Pulmonary Amyloidosis: Case Report and Literature Review

A 62-year-old woman was found to have multiple bilateral pulmonary nodules showing different ¹⁸F-fluorodeoxyglucose (FDG) uptakes on positron-emission tomography/computed tomography (PET/CT). Only the largest nodule in the left lower lobe showed an increased ¹⁸F-FDG uptake on PET/CT. Three nodules were surgically resected from different lobes of the left lung. Two lobes were benign and showed amyloid deposition. The largest nodule in the left lower lobe showed adenocarcinoma and a heavy amyloid deposition. Pulmonary amyloidosis should be added to the differential diagnosis for cases with multiple pulmonary nodules that show different ¹⁸F-FDG uptakes on PET/CT. To the best of our knowledge, this is the second reported case of a lung nodule consisting of adenocarcinoma and amyloid deposition.

18F-FDG PET scanning in pulmonary amyloidosis

(18)F-FDG PET plays an important role in the evaluation of patients with lung malignancies but can lead to false-positive and false-negative results. Very little is known about (18)F-FDG PET scanning in amyloidosis.

METHODS

A computer-assisted search of medical records was conducted to identify subjects with pulmonary amyloidosis (confirmed by biopsy) who were seen at the Mayo Clinic during a 15-y period between January 1, 1997, and December 31, 2011, and had a PET scan available for current review.

RESULTS

Eighteen patients were diagnosed to have amyloidosis by lung biopsy (15 surgical, 2 transthoracic needle, and 1 bronchoscopic). The mean age of the patients was 64.8 y (range, 32-80 y). Seventeen patients had primary amyloidosis, including 5 with Sjögren syndrome, 1 with rheumatoid arthritis, and 1 with multiple myeloma. The most common abnormal findings on the chest CT scan were pulmonary nodules (n = 14), followed by cysts (n = 6) and reticular opacities (n = 4). Eight patients had positive (18)F-FDG PET results (intrathoracic (18)F-FDG uptake), including 4 patients with coexisting mucosa-associated lymphoid tissue lymphoma (maximal standardized uptake value [SUVmax] range, 3.1-6.7) and 1 patient with a pleural plasmacytoma (SUVmax, 7.2); the remaining 3 patients had amyloid only (SUVmax range, 2.1-3.2). Ten patients with negative PET results included 3 additional patients with mucosa-associated lymphoid tissue lymphoma.

CONCLUSION

Positive (18)F-FDG PET results, especially with an SUVmax of more than 3, in patients with pulmonary amyloidosis should raise suspicion about associated lymphoma or plasmacytoma, but negative PET results do not exclude the presence of such neoplasms.

Utility of 18F-FDG PET(/CT) in patients with systemic and localized amyloidosis

PURPOSE

Amyloidosis is a group of diseases characterized by deposition of fibrils and this deposition may be localized or systemic. The presence of giant cells is typical of localized AL amyloidosis in contrast to systemic amyloidosis. Because of this presence of giant cells we hypothesize that (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) may show uptake in localized amyloidosis but not in systemic amyloidosis. The aim of the study was to evaluate the utility of (18)F-FDG PET/CT in distinguishing systemic amyloidosis from localized amyloidosis.

METHODS

A retrospective search in the hospital computer system showed 21 patients with histologically proven systemic or localized amyloidosis who recently had undergone (18)F-FDG PET/CT. Twenty patients also had undergone (123)I-serum amyloid P component (SAP) scintigraphy.

RESULTS

Of 11 patients with localized amyloidosis, 10 showed markedly increased FDG uptake at the amyloid site, whereas one showed slightly increased FDG uptake. (123)I-SAP scintigraphy (in ten patients) was positive in three patients at the amyloid site and negative for any other specific organ involvement in nine patients, with a weakly positive spleen in one other patient. In ten patients with systemic amyloidosis, increased FDG uptake was not found in any affected organ containing amyloid, whereas (123)I-SAP scintigraphy was positive for specific organ involvement in nine patients.

CONCLUSION

(18)F-FDG PET/CT may be supportive of the usual diagnostic tests in differentiating between systemic amyloidosis (no increased FDG uptake at the amyloid site) and localized amyloidosis (increased FDG uptake at the amyloid site). Apart from diagnosis, this finding has potential clinical application in therapy evaluation and follow-up.

Amyloid-associated cystic lung disease in primary Sjögren's syndrome

BACKGROUND

Cystic lung disease can be seen in patients with Sjögren's syndrome (SS) and is generally thought to be due to lymphocytic interstitial pneumonia.

METHODS

Using computer-assisted search we identified patients with primary SS seen at Mayo Clinic, Rochester, MN during a 14-year period from 1997 to 2010 who were diagnosed with pulmonary amyloidosis confirmed on lung biopsy. Clinical records, imaging studies, and pathologic specimens were reviewed to delineate presenting features, diagnostic evaluation, and clinical course.

RESULTS

Eight patients (7 women, 1 man) with primary SS were diagnosed with pulmonary amyloidosis by lung biopsy (7 surgical, 1 bronchoscopic). Their median age was 55 years (range, 32-75 years) and all were nonsmokers. Presenting symptoms included dyspnea and cough but 4 patients presented with radiologic abnormalities in the absence of respiratory symptoms. CT findings included cystic lesions and nodular opacities in all eight patients. PET scan performed in six patients did not reveal (18)F-2-deoxyglucose (FDG) uptake except in one nodule with borderline uptake. Lung biopsy demonstrated the presence of amyloid in all patients and was associated with mucosa-associated lymphoid tissue (MALT) lymphoma in three patients. Pulmonary function results were normal in five patients and revealed mild impairment in a mixed pattern in one patient.

CONCLUSIONS

We conclude cystic and nodular lung lesions seen in patients with primary SS can represent amyloidosis which can be associated with MALT lymphoma in some of these patients.

18F-FDG PET/CT in patients with amyloid light-chain amyloidosis: case-series and literature review

OBJECTIVES

To describe FDG-PET/CT in amyloid light-chain (AL) amyloidosis.

METHODS

We describe a French multicenter study which included patients with AL amyloidosis who had undergone a FDG-PET/CT during follow-up.

RESULTS

Ten patients with AL amyloidosis (median age 62 years [59-85]) were analyzed. AL amyloidosis was of λ-type in 7/10 cases (70%) and localized amyloidosis in 4/10 cases (40%). AL amyloidosis was primary in 7/10 (70%) cases and associated with Waldenstrom's macroglobulinemia (n = 2) and plasmocytoma (n = 1) in the remaining cases. Median delay between diagnosis and PET was 1 month [0-51]. PET was positive in seven (70%) patients and showed a median FDG SUV of 6.5 [ 4-15 ]. FDG uptakes with positive PET were localized in seven patients, namely in the nasopharynx (n = 3), bronchopulmonary (n = 2), duodenal, cutaneous, bone, joint and muscular areas (n = 1, each). FDG uptakes on PET were concordant with the known organ impairment in 6/7 cases (86%) and showed unknown nasopharyngeal and mesenteric localization in one case each. PET was negative in the patient with cardiac amyloidosis and two patients with pulmonary amyloidosis.

CONCLUSION

High FDG uptake may be present in patients with AL amyloidosis, however prospective studies are needed in order to determine the place of FDG PET in AL amyloidosis.