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.
A 64-year-old Caucasian female arrived by ambulance to our emergency room complaining of difficulty breathing. She was managed at several other hospitals before, but stated that her symptoms steadily became worse. She presented with generalized weakness, anasarca, nephrotic syndrome, decompensated heart failure, and leukocytosis with neutrophilia. Her serum protein electrophoresis showed hypoalbuminemia with hypo-gammaglobulinemia, as well as increased lambda and kappa light chains. Additionally, her urine tested positive for lambda light chains with nonselective uropathy. Her chest X-ray demonstrated cardiomegaly and bilateral pulmonary opacities. When our physicians discovered increased gamma-glutamyl transferase (gamma-GT) antibody levels, they suspected amyloidosis. They ordered a core needle fat pad biopsy, but it was negative.\nOnce physicians stabilized her heart and kidney failure, she was prepped for dialysis and discharged. She returned four days later to our emergency room with asystole. Computed tomography scan and X-ray imaging revealed chronic microvascular ischemic change with lucencies in the calvarium (). Radiologists suggested these findings could be seen in multiple myeloma or metastatic disease.\nShortly after completing these tests, she went into respiratory failure and was intubated, then admitted to the hospital. During her stay, she developed severe hypotension (84/55 mmHg), bradycardia (20–30 beats per minute), and bilateral pleural effusion. Chest compressions were performed on multiple occasions to keep her cardiac rhythm stable, while chest tubes were frequently draining fluid to manage the effusion. To assess for multiple myeloma, her physicians scheduled a bone marrow biopsy. However, they ultimately canceled the biopsy after they deemed she was too unstable to undergo the procedure. By this time, she had been intubated in the hospital for several weeks, and was beginning to show signs of multi-organ failure in the liver (macrocytic anemia and thrombocytopenia with increased ammonia, liver enzymes, prothrombin time, and partial thromboplastin time), as well as the kidney (burr cells and schistocytes on peripheral smear). Her family decided to withdraw care and consented for a full autopsy without any limitations performed by the hospital.\nClinicians performed a bed side core needle fat pad biopsy, in which three cores measuring 20 mm in length by 2 mm in diameter each (62.8 mm3 total) were submitted. Pathologists examined the biopsies using light microscopy with hematoxylin and eosin (H&E) and Congo-Red stained slides, as well as electron microscopy.\nWith a scalpel, a pathologist removed a thin piece of subcutaneous fat measuring 20 × 3.5 × 3 mm (210 mm3) from the area peripheral to the umbilicus. A second pathologist obtained a larger excisional fat pad biopsy from the area opposite of the first postmortem biopsy. The second biopsy was obtained using the procedure described by Garcia et al. and measured 9 × 8 × 8 mm (576 mm3) []. H&E and Congo-Red stains were utilized during light-microscopic examination of the biopsies. Fat pad, spleen, kidney, liver, and rectum samples were obtained for electron microscopy. Through immunofluorescence microscopy, pathologists inspected additional kidney tissue for lambda and kappa light chains. Our laboratory was unable to process the specimen for ATTR or further subtypes.\nReceived tissue samples were fixed for several hours in a 10% buffered formalin solution, then processed overnight (Leica Biosystems, Wetzlar, Germany). The processed tissue was embedded in paraffin wax and a 4 µm thick section was mounted on a charged glass slide. Then the sections were stained with H&E and Congo-Red. Pathologists examined the H&E slides via routine light microscopy. At the same microscope, they examined the Congo-Red slides using a detached polarizing filter.\nOur laboratory technologists applied a direct-labeling immunofluorescence protocol to kidney samples by using goat anti-human, fluorescein-conjugated antibodies for lambda and kappa light chains (Vector Laboratories, Inc., Burlingame, CA, USA). Sections obtained from the paraffin block were mounted on charged glass slides. After deparaffinizing the sections in xylene and hydrating with distilled water, slides were placed in a hot citrate solution for antigen retrieval. Subsequently, the sections were bathed in nonimmune horse serum, which acted as a blocking agent. Each slide consisted of two sections—a section for an antibody reaction and a negative control section where no antibody was applied. After a thirty-minute incubation followed by a buffer wash, a cover slip was mounted with glycerin and examined by an immunofluorescence microscope.\nFor the transmission electron microscopy (TEM) analysis, tissue samples were fixed with 3% glutaraldehyde buffered by 0.2 M sodium cacodylate (pH = 7.2) for thirty minutes at 37 °C. The samples were post-fixed for two hours at room temperature with 1% osmium tetroxide followed by one hour in a saturated, uranyl-acetate aqueous solution for tertiary fixation. The tissue on the slides were then dehydrated through a graded series of ethanol. The culture plates were scraped with a rubber policeman and mixed with 100% acetone with the embedding media. Then, tissue samples were embedded in Embed 812 epoxy resin (Electron Microscope Sciences, Fort Washington, PA, USA) and ultrathin sections were collected on 300-mesh copper support grids. After staining sections with uranyl acetate and Reynold’s lead citrate, the sections were examined with a FEI Tecnai T20 TEM at 80 kV. To determine the size of the amyloid fibrils, 50–80 random widths and diameters of fibrils were assessed with a calibrated measurement tool included in the Olympus Soft Imaging Radius software.\nGross examination found multiple organs to be firm and waxy, including the heart, spleen, kidneys, and liver. The spleen demonstrated a diffuse pale-yellow infiltrate throughout the parenchyma consistent with a lardaceous pattern (). Sago and lardaceous are two specific gross patterns identified in spleens that are involved by amyloidosis [,].\nThe heart had right and left ventricular hypertrophy, and the cortexes of both kidneys were expanded. The thyroid, both adrenal glands, and the rectum appeared grossly normal.\nH&E-stained sections of the heart, thyroid, liver, spleen, rectum, kidneys, and adrenal glands showed hyaline extracellular matrix (). In the spleen, this matrix was located within the red pulp and sinusoids, consistent with the lardaceous pattern identified on gross examination [,]. Bone marrow scraping of the rib revealed extracellular matrix (A) surrounding cells with CD138-positive staining, which confirmed plasma cell dyscrasia (B). Congo-Red stained sections of the right kidney demonstrated apple-green birefringence in blood vessel walls (C). Immunofluorescence microscopy showed positive reactions to lambda light chains in the mesangium and basement membranes in the glomeruli of the right kidney (D).\nIn the spleen, liver, kidney (A,B), and rectum (C,D), electron microscopy revealed the hyalinized material consisted of 8–11 nm diameter fibrils deposited in a haphazard pattern of beaded filaments. The resolution of these fibrils was partially compromised due to the tissue being taken at autopsy instead of a live tissue biopsy.\nConsistent with the negative fat pad biopsy obtained antemortem, the postmortem fat pad biopsies did not show any of these positive features on light microscopy or electron microscopy.\nPathologists determined the cause of death was multi-organ failure due to systemic light chain gammopathy. Due to the presence of CD138-positive cells in the bone marrow scraping, plasma cell dyscrasia most likely caused this gammopathy. Although the patient presented with proteinuria, increased free serum light chains, and osteolytic bone lesions, clinicians did not report a diagnosis of multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS) at the time of autopsy. Therefore, the final autopsy report did not include these diagnoses.