A 60-year-old man with history of left nephrectomy for clear cell renal cancer (stage I) and resected colorectal adenocarcinoma (stage II) presented with a pulmonary mass lesion in the left upper lobe on surveillance imaging. Transaxial CT (B) revealed a 2.9 cm slightly lobulated lesion in the inferior lingular segment of the left upper lobe overlying the left oblique fissure. 18-F FDG PET/CT images (A, C, D) demonstrated moderate to marked FDG avidity (SUVmax 6.4) in this lesion.\nHistopathology of CT-guided core needle biopsy showed tumour cells with relatively uniform nuclear and clear cell cytoplasm with positive staining for PAX8 and renal cell antigen, consistent with metastatic renal cell carcinoma. The patient underwent wedge resection of the left upper lobe metastasis with clear excisional margins.\n6 months later, follow-up imaging with 18-F FDG PET/CT and diagnostic CT was performed. Transaxial CT (B) demonstrated a slowly enlarging subcentimeter 9mm pulmonary nodule in the right upper lobe. Maximum intensity projection, transaxial fused PET/CT and transaxial PET (A, C, D) images demonstrated moderate FDG avidity (SUVmax 4.6 on current PET, SUVmax 2.4 on previous PET (not shown)) in this lesion. No other suspicious FDG avid focus was detected. Given the proven pulmonary metastatic disease from renal cell cancer, further small volume oligometastatic disease was suspected. Reliable needle biopsy of the lesion was considered difficult due its small size and deep location. The patient subsequently underwent segmental resection of this sub centimeter pulmonary nodule.\nHistopathology of the second pulmonary nodule demonstrated no evidence of malignancy. Instead, there was amorphous hyaline acellular amyloid-like material associated with a rim of multinucleated inflammatory cells (). The chronic inflammatory cells comprised mainly of mature plasma cells with smaller numbers of lymphocytes. Crystal violet stain was positive, and the Congo red stain demonstrated focal birefringence, confirming nodular pulmonary amyloidosis. The patient continues to be under observation for further tumour recurrence.
A 71-year-old woman was investigated for a one-year history of deteriorating dyspnoea on a background of well-controlled asthma. Other co-morbidities included cutaneous systemic lupus erythematosus, rheumatoid arthritis and Sjogren’s syndrome. High-resolution computerised tomography (HRCT) showed multiple cysts, solid nodules and aggregate masses – the largest (2 × 1.5 cm) in the peripheral left lower lobe with fine-needle aspiration suggestive of amyloid. Serum biochemistry showed a polyclonal elevation of IgG, no detectable monoclonal band and normal serum-free light chains. Immunohistochemistry showed no specific staining for kappa or lambda antibodies. Mass spectrometry was not performed. Echocardiography excluded cardiac involvement and no visceral uptake by 123I SAP scintigraphy. Pulmonary function tests demonstrated a restrictive pattern, and a further HRCT raised suspicion of lymphocytic interstitial pneumonitis. FDG-PET/CT demonstrated similar low-grade uptake in all lung nodules (). A mini-thoracotomy was performed to obtain tissue from the largest nodule showing evidence of amyloid but too few infiltrating cells were present to confirm clonality.\nA low-grade lymphoplasmocytic lymphoma (LPL) was presumed to be driving the pulmonary amyloid, based on the assumption of low-grade B-cell clonal disorders that can occur with Sjogren’s syndrome. A trial of R-CVP (Rituximab – Cyclophoshamide, Vincristine, Prednisolone) chemotherapy was commenced for four months resulting in no progression of symptoms and stable lesions.