Pulmonary Light and Heavy Chain Deposition Disease

Abstract

A 64-year-old man with a history of smoking and asbestos exposure was referred for an F-18 FDG PET/CT, to evaluate multiple growing lung nodules that had been found incidentally on prior chest CTs. The PET/CT showed multiple hypermetabolic nodules in both the lungs, with varying intensity of FDG uptake, raising the suspicion of multifocal malignancy. Wedge resections of the right lung were done to remove the 2 most hypermetabolic nodules, and histologic evaluation revealed pulmonary light and heavy chain deposition disease. A follow-up PET/CT performed 1 year later showed another slowly growing nodule in the left lung with a significant increase in F-18 FDG uptake. Only 22 cases of pulmonary light chain deposition disease have been reported in the literature. This is a report of F-18 FDG uptake in nodules of pulmonary light chain deposition disease. These nodules can grow in size and can show increased F-18 FDG uptake on follow-up studies, mimicking a growing lung malignancy. man with a history of smoking and asbestos exposure had a contrast-enhanced chest CT for evaluation of pulmonary embolism. An incidental 8-mm nodule was noted in the right upper lung, laterally. B, In August 2008, the patient had another contrast-enhanced chest CT, following a motor vehicle accident. The right upper lung nodule had grown to 1.4 ϫ 1.0 cm and was not calcified. The patient was referred for a PET/CT. C, On the F-18 FDG PET/CT (Discovery ST, GE Healthcare), the 1.4 cm right upper lobe lung nodule had a maximal Standardized uptake value (SUV) of 6.3. There was another subcentimetric nodule in the right lower lobe with SUV 3.5, and an ill-defined 1 cm nodule in the left upper lobe with SUV 1.7. A suspicion for multifocal malignancy was raised. Histologic evaluation of wedge resections of the right upper and right lower lobes showed nodules of amorphous eosinophilic material, congo red negative, with plasma cells expressing kappa light and IgG heavy chains, consistent with monoclonal pulmonary light and heavy chain deposition disease. The diagnosis was confirmed with electron microscopy, which showed linear or nodular deposits of amorphous and granular material in vessel walls and in the interstitium consistent with those found in light and heavy chain deposition diseases. Nonbranching fibrils of 7.5 to 10 nm, characteristic of amyloid, were not seen. Molecular studies showed the presence of a clonal population of B-cells for FR3 (framework region) and for J kappa, and absence of a clonal population of T-cells for T gamma I and II. Molecular studies for FR1 were equivocal, and those for FR2 were negative. D, PET/CT fusion image.

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

“…7 As they can show suspicious morphological features and high uptake of 18 F-FDG similar to bronchial carcinoma or other malignancies, differentiation with CT and 18 F-FDG PET/CT can be difficult. [8][9][10][11][12][13][14] This case demonstrates the similarities of pulmonary amyloidoma and malignancies on morphological and molecular imaging and highlights the importance of histological evaluation to confirm the diagnosis.…”

“…However, pulmonary manifestation of the nodular parenchymal pattern, especially a large tumor-like/mass-like deposition, described as “amyloidoma” of the lung, without coexistence of any systemic disease, is rare 7 . As they can show suspicious morphological features and high uptake of 18 F-FDG similar to bronchial carcinoma or other malignancies, differentiation with CT and 18 F-FDG PET/CT can be difficult 8–14 . This case demonstrates the similarities of pulmonary amyloidoma and malignancies on morphological and molecular imaging and highlights the importance of histological evaluation to confirm the diagnosis.…”

Primary osteosarcoma of the thyroid gland – a

“…The extraosseous form of osteosarcoma occurs very rarely (approx. 5%), especially in the thyroid, where, so far, it has been diagnosed in 28 cases [5], and in only two cases with fine-needle biopsy [6, 7]. This tumour is characterised by fast growth and requires quick surgical intervention due to pressure-related symptoms of dyspnoea.…”