Pathological Society of Great Britain and Ireland. 154th meeting, 7-9 January 1987. Synopses of papers

Modelling of macrophage responses to biomaterials in vitro: state-of-the-art and the need for the improvement

The increasing use of medical implants in various areas of medicine, particularly in orthopedic surgery, oncology, cardiology and dentistry, displayed the limitations in long-term integration of available biomaterials. The effective functioning and successful integration of implants requires not only technical excellence of materials but also consideration of the dynamics of biomaterial interaction with the immune system throughout the entire duration of implant use. The acute as well as long-term decisions about the efficiency of implant integration are done by local resident tissue macrophages and monocyte-derived macrophages that start to be recruited during tissue damage, when implant is installed, and are continuously recruited during the healing phase. Our review summarized the knowledge about the currently used macrophages-based in vitro cells system that include murine and human cells lines and primary ex vivo differentiated macrophages. We provided the information about most frequently examined biomarkers for acute inflammation, chronic inflammation, foreign body response and fibrosis, indicating the benefits and limitations of the model systems. Particular attention is given to the scavenging function of macrophages that controls dynamic composition of peri-implant microenvironment and ensures timely clearance of microorganisms, cytokines, metabolites, extracellular matrix components, dying cells as well as implant debris. We outline the perspective for the application of 3D systems for modelling implant interaction with the immune system in human tissue-specific microenvironment avoiding animal experimentation.

Dentate Gyrus Granule Cells Show Stability of BDNF Protein Expression in Mossy Fiber Axons with Age, and Resistance to Alzheimer's Disease Neuropathology in a Mouse Model

Brain-derived neurotrophic factor (BDNF) is important in the development and maintenance of neurons and their plasticity. Hippocampal BDNF has been implicated in Alzheimer's disease (AD) because hippocampal levels in AD patients and AD animal models are often downregulated, suggesting that reduced BDNF contributes to AD. However, the location where hippocampal BDNF protein is most highly expressed, the mossy fiber (MF) axons of dentate gyrus granule cells (GCs), has been understudied, and not in controlled conditions. Therefore, we evaluated MF BDNF protein in the Tg2576 mouse model of AD. Tg2576 and wild-type (WT) mice of both sexes were examined at 2-3 months of age, when amyloid-β (Aβ) is present in neurons but plaques are absent, and 11-20 months of age, after plaque accumulation. As shown previously, WT mice exhibited high levels of MF BDNF protein. Interestingly, there was no significant decline with age in either the genotype or sex. Notably, MF BDNF protein was correlated with GC ΔFosB, a transcription factor that increases after 1-2 weeks of elevated neuronal activity. We also report the novel finding that Aβ in GCs or the GC layer was minimal even at old ages. The results indicate that MF BDNF is stable in the Tg2576 mouse, and MF BDNF may remain unchanged due to increased GC neuronal activity, since BDNF expression is well known to be activity dependent. The resistance of GCs to long-term Aβ accumulation provides an opportunity to understand how to protect vulnerable neurons from increased Aβ levels and therefore has translational implications.

Stability of dentate gyrus granule cell mossy fiber BDNF protein expression with age and resistance of granule cells to Alzheimer's disease neuropathology in a mouse model

The neurotrophin brain-derived neurotrophic factor (BDNF) is important in development and maintenance of neurons and their plasticity. Hippocampal BDNF has been implicated Alzheimer's disease (AD) because hippocampal levels in AD patients and AD animal models are consistently downregulated, suggesting that reduced BDNF contributes to AD. However, the location where hippocampal BDNF protein is most highly expressed, the mossy fiber (MF) axons of dentate gyrus (DG) granule cells (GCs), has been understudied, and never in controlled in vivo conditions. We examined MF BDNF protein in the Tg2576 mouse model of AD. Tg2576 and wild type (WT) mice of both sexes were examined at 2-3 months of age, when amyloid-β (Aβ) is present in neurons but plaques are absent, and 11-20 months of age, after plaque accumulation. As shown previously, WT mice exhibited high levels of MF BDNF protein. Interestingly, there was no significant decline with age in either genotype or sex. Notably, we found a correlation between MF BDNF protein and GC ΔFosB, a transcription factor that increases after 1-2 weeks of elevated neuronal activity. Remarkably, there was relatively little evidence of Aβ in GCs or the GC layer even at old ages. Results indicate MF BDNF is stable in the Tg2576 mouse, and MF BDNF may remain unchanged due to increased GC neuronal activity, since BDNF expression is well known to be activity-dependent. The resistance of GCs to long-term Aβ accumulation provides an opportunity to understand how to protect other vulnerable neurons from increased Aβ levels and therefore has translational implications.

Renal amyloidosis: Pathogenesis

For many years amyloidosis was considered an extremely rare, somewhat mysterious disease. However, in the last 2-3 decades its pathogenesis, particularly that of renal amyloidosis has been carefully dissected in the research laboratory using in-vitro and, to a lesser extent, in-vivo models. These have provided a molecular understanding of sequential events that take place in the renal mesangium leading to the formation of amyloid fibrils and eventual extrusion into the mesangial matrix, which itself becomes seriously damaged and, in due time, replaced by the fibrillary material. Amyloid, once considered to be an "inert" substance, has been proven to be involved in crucial biological processes that result in the destruction and eventual replacement of normal renal constituents. This review centers on mechanisms involved in the renal glomerular amyloidosis to understand its pathogenesis.

Autopsy findings in a patient with primary systemic AL (kappa light chain) amyloidosis

First described by Rokitansky in 1842, and further characterized by Virchow in 1854, amyloidosis is a disorder caused by amyloid deposition, a fibrillary insoluble protein. The clinical spectrum of amyloidosis is broad, as the amyloid deposition may virtually occur in all tissues. Herein, we report the case of a 66-year-old man with a long-lasting emaciating disease, diagnosed, at autopsy, with primary systemic amyloidosis. Amyloid protein deposition was found in many tissues and organs. The involvement of the vessels’ wall rendered ischemic injury most prominent in the intestinal loops causing mesenteric ischemia. Despite the thorough organic involvement, the immediate cause of death was aspiration bronchopneumonia. Massive amyloid deposition was found in virtually all major organs, such as the heart, liver, kidneys, spleen, pancreas, adrenals, prostate, skin, and thyroid: the latter, a complication of the amyloidosis known as amyloid goiter. Post-mortem review of the deceased’s laboratory workup showed a slightly abnormal kappa:lambda ratio in the blood; however, no clonal lymphoplasmacytic disorder was confirmed in the bone marrow and other lymphoreticular system organs either by the microscopic examination and immunohistochemical staining. Laser-capture microdissection and tandem mass spectrometry of the splenic tissue detected a peptide profile consistent with an immunoglobulin Kappa light chain. The presence of amyloid purpura favors the diagnosis of primary systemic amyloidosis.

Synthesis and characterization of a multimode stationary phase: Congo red derivatized silica in nano-flow HPLC

Congo red derivatized silica has been developed as a mixed mode stationary phase and used for nano-flow HPLC.

Surgical considerations about amyloid goiter

Amyloidosis is an uncommon syndrome consisting of a number of disorders having in common an extracellular deposit of fibrillary proteins. This results in functional and structural changes in the affected organs, depending on deposit location and severity. Amyloid infiltration of the thyroid gland may occur in 50% and up to 80% of patients with primary and secondary amyloidosis respectively. Amyloid goiter (AG) is a true rarity, usually found associated to secondary amyloidosis. AG may require surgical excision, usually because of compressive symptoms. We report the case of a patient with a big AG occurring in the course of a secondary amyloidosis associated to polyarticular onset juvenile idiopathic arthritis who underwent total thyroidectomy. Current literature is reviewed, an attempt is made to provide action guidelines, and some surgical considerations on this rare condition are given.

Multiple myeloma-associated iliopsoas muscular amyloidoma first presenting with bilateral femoral nerve entrapment

We report a 38-year-old man of multiple myeloma with bilateral femoral nerve entrapment caused by bilateral huge protruding masses in the inguinal areas. The masses were identified as iliopsoas muscular amyloidoma after the operation. He was diagnosed with multiple myeloma 1 year ago before he was admitted to our hospital. He complained of muscle weakness in the bilateral thigh and protruding lumps in the bilateral inguinal areas with tenderness for 6 month. The pelvic MRI revealed round masses in the iliopsoas muscles of bilateral inguinal areas. To implement the nerve decompression, the resection of the bilateral masses was done. The pathological result showed Congo red-positive substance with green birefringence to polarized light in a dense fibrous background. Before the operation, six cycles of chemotherapy with VAD (vincristine, adriamycin, dexamethasone) and two cycles of chemotherapy with PAD (bortezomib, adriamycin, dexamethasone) regimen were performed. One month after the operations, one cycle of chemotherapy with PADT (bortezomib, adriamycin, dexamethasone, thalidomide) regimen was used and the patient reached complete remission. The function of the bilateral femoral nerves restored to normal 7 months after the operation with a Karnofsky score of 100. Twenty-two months follow-up showed that there was no evidence of the recurrence of the iliopsoas muscular amyloidoma and no progression of multiple myeloma.

Are synucleinopathies prion-like disorders?

A shared neuropathological feature of idiopathic Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy is the development of intracellular aggregates of α-synuclein that gradually engage increasing parts of the nervous system. The pathogenetic mechanisms underlying these neurodegenerative disorders, however, are unknown. Several studies have highlighted similarities between classic prion diseases and these neurological proteinopathies. Specifically, identification of Lewy bodies in fetal mesencephalic neurons transplanted in patients with Parkinson's disease raised the hypothesis that α-synuclein, the main component of Lewy bodies, could be transmitted from the host brain to a graft of healthy neurons. These results and others have led to the hypothesis that a prion-like mechanism might underlie progression of synucleinopathy within the nervous system. We review experimental findings showing that misfolded α-synuclein can transfer between cells and, once transferred into a new cell, can act as a seed that recruits endogenous α-synuclein, leading to formation of larger aggregates. This model suggests that strategies aimed at prevention of cell-to-cell transfer of α-synuclein could retard progression of symptoms in Parkinson's disease and other synucleinopathies.

Single cell gene expression profiling in Alzheimer's disease

Development and implementation of microarray techniques to quantify expression levels of dozens to hundreds to thousands of transcripts simultaneously within select tissue samples from normal control subjects and neurodegenerative diseased brains has enabled scientists to create molecular fingerprints of vulnerable neuronal populations in Alzheimer's disease (AD) and related disorders. A goal is to sample gene expression from homogeneous cell types within a defined region without potential contamination by expression profiles of adjacent neuronal subpopulations and nonneuronal cells. The precise resolution afforded by single cell and population cell RNA analysis in combination with microarrays and real-time quantitative polymerase chain reaction (qPCR)-based analyses allows for relative gene expression level comparisons across cell types under different experimental conditions and disease progression. The ability to analyze single cells is an important distinction from global and regional assessments of mRNA expression and can be applied to optimally prepared tissues from animal models of neurodegeneration as well as postmortem human brain tissues. Gene expression analysis in postmortem AD brain regions including the hippocampal formation and neocortex reveals selectively vulnerable cell types share putative pathogenetic alterations in common classes of transcripts, for example, markers of glutamatergic neurotransmission, synaptic-related markers, protein phosphatases and kinases, and neurotrophins/neurotrophin receptors. Expression profiles of vulnerable regions and neurons may reveal important clues toward the understanding of the molecular pathogenesis of various neurological diseases and aid in identifying rational targets toward pharmacotherapeutic interventions for progressive, late-onset neurodegenerative disorders such as mild cognitive impairment (MCI) and AD.

Muscular amyloidoma presenting as inguinal masses in multiple myeloma

We report a case with protruding inguinal masses for 6 months, in whom muscular amyloidoma was not suspected before muscle biopsy. On pelvic magnetic resonance imaging (MRI), round masses showing peripheral rim enhancement with gadolinium were observed in iliopsoas and iliacus muscles of both inguinal areas. The same lesions were also observed in gluteus muscles. The biopsy showed Congo red positive materials in a dense fibrous background. Serum and urine electrophoresis showed Bence Jones protein, lambda type. In bone marrow section, myeloma cells were found. Peripheral blood stem cell transplantation (PBSCT) following four cycles of VAD (vincristine, adriamycin, dexamethasone) chemotherapy was performed and the result was satisfactory. Amyloidoma lesions decreased in size and number on the following MRI.

Amyloid Tumor of the Larynx associated with Plasma Cell Infiltration: Differential Diagnosis

Localized amyloidosis of the larynx is uncommon, accounting for fewer than 1 % of all benign laryngeal tumors. We report 2 cases of laryngeal amyloidosis in which dense plasma cell infiltrates were found in the vicinity of the amyloid deposits; in view of this finding, we suspected a hematologic disease—plasmacytoma in particular. However, molecular genetic analysis did not demonstrate any light-chain restriction, indicating that the plasma cells were of polyclonal origin and therefore consistent with chronic inflammation. We also discuss the available literature with respect to diagnostic and therapeutic procedures inpatients with amyloidosis of the upper airway.

Localized amyloidosis of the cornea secondary to trichiasis: clinical course and pathogenesis

PURPOSE

To present four cases of localized corneal amyloidosis secondary to trichiasis and to discuss its pathogenesis.

METHODS

Medical and pathologic records of four patients with corneal amyloidosis secondary to trichiasis were reviewed retrospectively. Two patients underwent trichiasis surgery and then lamellar keratectomy. One patient underwent trichiasis surgery only, and one patient received keratectomy only. The excised specimens were examined by light and electron microscopy. In two cases, they were stained with antibodies against kappa and lambda immunoglobulin light chains. All patients were followed for evidence of progression or recurrence of the lesions.

RESULTS

Three cases presented with blurring of vision and a progressively enlarging vascularized unilateral corneal mass. One case had normal vision and a smaller, nonvascularized mass. All four cases had a history of trichiasis. After trichiasis surgery but before corneal surgery, two patients were followed for 24 and 18 months, respectively, and showed no progression of the corneal lesions. The patient who did not undergo trichiasis surgery had a recurrence of the corneal lesion after lamellar keratectomy. Pathologic examination confirmed amyloid deposition in all three excised specimens with almost no inflammatory cells. Immunohistochemical stains were negative.

CONCLUSION

The close correlation between trichiasis surgery and the clinical course of corneal amyloidosis provides further evidence for their association. The pathologic findings in this study do not confirm that the amyloid deposits are light chain proteins (AL).

The V122I cardiomyopathy variant of transthyretin increases the velocity of rate-limiting tetramer dissociation, resulting in accelerated amyloidosis

The transthyretin (TTR) amyloid diseases are of keen interest, because there are >80 mutations that cause, and a few mutations that suppress, disease. The V122I variant is the most common amyloidogenic mutation worldwide, producing familial amyloidotic cardiomyopathy primarily in individuals of African descent. The substitution shifts the tetramer-folded monomer equilibrium toward monomer (lowers tetramer stability) and lowers the kinetic barrier associated with rate-limiting tetramer dissociation (pH 7; relative to wild-type TTR) required for amyloid fibril formation. Fibril formation is also accelerated because the folded monomer resulting from the tetramer-folded monomer equilibrium rapidly undergoes partial denaturation and self-assembles into amyloid (in vitro) when subjected to a mild denaturation stress (e.g., pH 4.8). Incorporation of the V122I mutation into a folded monomeric variant of transthyretin reveals that this mutation does not destabilize the tertiary structure or alter the rate of amyloidogenesis relative to the wild-type monomer. The increase in the velocity of rate-limiting tetramer dissociation coupled with the lowered tetramer stability (increasing the mol fraction of folded monomer present at equilibrium) may explain why V122I confers an apparent absolute anatomic risk for cardiac amyloid deposition.

Polyglandular endocrine failure in a patient with amyloidosis secondary to familial Mediterranean fever

Familial Mediterranean fever (FMF) is 1 of the major causes of secondary amyloidosis. Renal involvement is the main clinical complication and it mostly presents with nephrotic syndrome and chronic renal failure. Although deposition of amyloid has been reported in several endocrine glands such as the adrenal, thyroid, and testes, clinically significant functional impairment is uncommon. Herein, we describe a patient in whom the diagnosis of FMF was based on molecular screening and who presented with recurrent hypoglycemic attacks and extensive amyloid deposition affecting various organ function including adrenal, thyroid, parathyroid, testes, intestinal system, and the heart.

Renal lesions in leprosy: a retrospective study of 199 autopsies

In the present work, 199 patients with leprosy who underwent autopsy between 1970 and 1986 were retrospectively studied to determine the prevalence, types, clinical characteristics, and etiologic factors of renal lesions (RLs) in leprosy. Patients were divided into two groups: 144 patients with RLs (RL+) and 55 patients without RLs (RL-). RLs observed in 72% of the autopsied patients were amyloidosis (AMY) in 61 patients (31%), glomerulonephritis (GN) in 29 patients (14%), nephrosclerosis (NPS) in 22 patients (11%), tubulointerstitial nephritis (TIN) in 18 patients (9%), granuloma in 2 patients (1%), and other lesions in 12 patients (6%). AMY occurred most frequently in patients with lepromatous leprosy (36%; nonlepromatous leprosy, 5%; P < 0.01), recurrent erythema nodosum leprosum (33%; P < 0.02), and trophic ulcers (27%; 0.05 < P < 0.10). Ninety-seven percent of AMY was found in patients with lepromatous leprosy, 88% showed recurrent trophic ulcers, and 76% presented with erythema nodosum leprosum. NPS was found in older patients with arterial hypertension, neoplastic diseases, infectious diseases, and vasculitis associated with GN. Most patients with AMY presented with proteinuria (95%) and renal failure (88%). The most frequent causes of death were renal failure in patients with AMY (57%), infectious diseases in patients with GN (41%) and TIN (45%), and cardiovascular diseases in patients with NPS (41%). No difference in survival rates was observed among RL- patients and those with AMY, GN, NPS, or TIN.

Amyloidoma of the thoracic spine. Case report

The authors report the case of a patient with amyloidoma of the thoracic spine. A 34-year-old man presented with a 2-month history of upper-back pain, bilateral lower-extremity weakness, and numbness below the nipple. A computerized tomography study revealed an extradural mass with destruction of the T-2 lamina and pedicle. Intraoperatively, there was a pinkish, partially suctionable mass infiltrating the muscle plane and causing destruction of the T-2 lamina. Histological examination showed typical amyloid masses that demonstrated apple-green double refraction on examination of the Congo red-stained section under polarized light. Amyloidomas are rare benign lesions that, unlike other forms of amyloidosis, have an excellent prognosis. A cure is possible with complete resection of the mass.

Amyloidoma in the gasserian ganglion: case report

BACKGROUND

Amyloidoma in the central nervous system is extremely rare. We describe a rare case of amyloidoma in the gasserian ganglion manifesting as trigeminal neuropathy.

METHODS

A 41-year-old woman was admitted to our hospital with progressive numbness and hypalgesia in the distribution of the second and third divisions of the left trigeminal nerve. There was no evidence of chronic inflammatory disorder or immunological abnormalities. Magnetic resonance images showed a mass in the left Meckel's cave that was brightly enhanced with gadolinium.

RESULTS

A reddish, firm mass was successfully removed via a left temporal craniotomy. Histologically, the tumor was composed of larger acellular deposits of eosinophilic material. The acellular deposits were positive for potassium permanganate-resistant Congo red staining, showing apple-green birefringence under polarized light and expression of immunoglobulin lambda light chain-derived proteins (A lambda) immunohistochemically.

CONCLUSION

The present case revealed an A lambda amyloidoma in the left gasserian ganglion. Although the incidence is rare, amyloidoma should be suspected in patients who complain of progressive trigeminal neuropathies and show an enhanced lesion in the gasserian ganglion on MR images.

Familial Amyloidotic Polyneuropathy: domino liver transplantation

BACKGROUND/AIMS

The primary cause of Familial Amyloidotic Polyneuropathy is a variant transthyretin gene on chromosome 18. Progressive polyneuropathy followed by fatal cardiac and renal failure commonly manifest during middle age. Within 10 years after onset of clinical symptoms, affected individuals usually die due to malnutrition or heart failure. Currently, liver transplantation is the only available therapeutic option.

METHODS

We performed liver transplantation in two patients with Familial Amyloidotic Polyneuropathy carrying the transthyretin-30 mutant. Two patients aged more than 50 years received the two explanted amyloidotic livers. This procedure is called Domino liver transplantation. We report the outcome in the studied subjects and analyze the metabolic consequences of this procedure.

RESULTS

We determined the serum half-life of transthyretin-30 as 2.25 days using daily monitoring of transthyretin-30 levels. An affected amyloidotic patient had an increased serum concentration of lipoprotein(a) of 78 mg/dl before transplantation. The tumor patient, who received the organ from this affected patient, developed an almost identical serum concentration of lipoprotein(a) after liver transplantation, confirming the liver as the primary site of synthesis of this lipoprotein.

CONCLUSION

Once Domino liver transplantation has been performed, the impact of the liver-dependent metabolism of specific proteins of interest can be studied.

Systemic amyloidosis and the gastrointestinal tract

Systemic amyloidosis is caused by a variety of different diseases and frequently involves the gastrointestinal tract. Each type of amyloid affects the gastrointestinal tract differently. This article reviews the unique pathogenesis, pattern of gastrointestinal disposition, diagnosis, and treatment of the five systemic amyloidoses, and discusses the gastrointestinal diseases that cause systemic amyloidosis: inflammatory bowel disease and familial Mediterranean fever.

Serum amyloid A and P protein levels are lowered by dextran sulfate cellulose low-density lipoprotein apheresis

The present study describes the short-term effect of dextran sulfate cellulose (DSC) low-density lipoprotein (LDL) apheresis using a plasma separator equipped with a polysulfone (PS) membrane filter (PS/DSC-LDL apheresis) on the serum amyloid A (SAA) and P (SAP) protein levels during treatment in a patient with familial hypercholesterolemia (type IIa, heterozygote). PS/DSC-LDL apheresis markedly lowered both the SAA (reduction percentage, 84.1+/-8.2%) and SAP (91.4+/-5%) levels, which returned to their respective initial levels within 4 days. Experimentally, the levels of both proteins also decreased on passage through the DSC minicolumn without a PS membrane, indicating that the DSC resin had an affinity to both proteins. These results suggest that PS/DSC-LDL apheresis may be advantageous for amyloid protein accumulating disorders, including amyloidosis and atherosclerosis.

Human choroid plexus is an uniquely involved area of the brain in amyloidosis: a histochemical, immunohistochemical and ultrastructural study

To better understand the characteristics of amyloid deposition in the choroid plexus, we examined autopsied brain by routine histology, immunohistochemistry, and electron microscopy in three group of patients: primary systemic amyloidosis (n = 7), cerebral amyloid angiopathy (CAA, n = 6), and controls (n = 3). Three of the CAA patients had Alzheimer's disease. Congophilic, birefringent amyloid deposits of the choroid plexus were seen in six of the seven cases of systemic light chain amyloidosis. Immunohistochemistry revealed that the deposited amyloids had reactivity for immunoglobulin light chain and amyloid P component. Accumulation of macrophages labeled with monoclonal antibodies against CD 68 and major histocompatibility complex class II antigens were observed around the massive amyloid deposits. The presence of approximately 10 nm amyloid fibrils along the epithelial basement membrane as well as in the vascular walls was ascertained by electron microscopy. In CAA, Congo red-positive amyloid deposits were consistently present in meningeal blood vessels and were often found in senile plaques of the cerebral parenchyma; congophilic amyloid deposits were absent in the choroid plexus. Choroid plexus epithelial cells exhibited immunostaining for beta amyloid precursor protein (APP) with N-terminal- and C-terminal-specific antibodies; in particular, consistent staining was obtained for the latter antibody. Immunoreactivity for amyloid beta protein (A beta) with monoclonal antibodies (6E10, 4G8) was often found in choroid plexus epithelial cells. These findings suggest that amyloid deposition of the choroid plexus depends on the major component protein in amyloidosis, and that the choroid plexus may produce APP and A beta protein although A beta amyloidosis is not evident in the choroid plexus.

Monoclonal origin of localised orbital amyloidosis detected by molecular analysis

AIMS

Primary localised orbital amyloidosis is a rare disease. The purpose of this study was to describe two cases of primary orbital amyloidosis and emphasise the value of molecular analysis of immunoglobulin gene rearrangement in identifying a monoclonal population of cells responsible for the amyloid production.

METHODS

Charts and biopsy specimens of each case were reviewed. Conventional light microscopy, immunohistochemistry, and polymerase chain reaction (PCR) analysis for immunoglobulin gene rearrangement were performed in both cases.

RESULTS

An unusual presentation of localised primary amyloidosis with bilateral and extensive enlargement of multiple extraocular muscles was seen in case 1. The presence of amyloid deposits was confirmed by biopsy in both cases. Evidence of a monoclonal population of plasma cells was shown by immunohistochemical analysis in case 2 only. The monoclonal origin of the cells responsible for the amyloid deposition was determined by PCR analysis demonstrating immunoglobulin heavy chain gene rearrangement in both cases.

CONCLUSIONS

A monoclonal population of plasma cells responsible for the amyloid deposition was present in these two cases. PCR analysis is extremely helpful in determining monoclonality, a finding that may have important therapeutic and prognostic implications.

Systemic AA amyloidosis induced by oral contraceptive-associated hepatocellular adenoma: a 13-year follow up

We report a case of a woman who showed hepatic and renal AA amyloidosis with a liver adenoma associated with the use of oral contraceptives. A nephrotic syndrome secondary to the renal amyloidosis underwent complete remission 7 years after the withdrawal of oral contraceptive therapy. Twenty-nine months after the initial presentation, the patient was admitted with acute upper abdominal pain and abdominal tenderness. The abdominal ultrasound revealed a subphrenic fluid collection, and a presumptive diagnosis of a ruptured hepatic adenoma was made. The liver adenoma diminished from 8 cm to 1 cm over a 13-year follow up after the discontinuance of oral contraceptive therapy.

Amyloid goiter in cystic fibrosis

Chronic infectious or inflammatory diseases lead to amyloid infiltration and dysfunction of many organs, including the kidney, liver, heart, and gastrointestinal tract. Subclinical amyloid infiltration of the thyroid gland has been described in over 80% of such patients. However, symptomatic involvement of the thyroid gland by amyloid is rare. We describe a euthyroid patient with cystic fibrosis and widespread amyloidosis who presented with a rapidly enlarging goiter and symptoms of local compression that compromised his pulmonary status. Fine needle aspiration of the goiter was nondiagnostic. At surgery he proved to have replacement of the thyroid gland by amyloid. A review of the literature reveals only five previous cases of amyloid goiter in patients with cystic fibrosis. However, as more patients survive into adulthood, amyloid goiter may become a more common complication of cystic fibrosis. In contrast to other patients with reactive amyloidosis and goiter, patients with cystic fibrosis may require thyroid surgery to relieve airway compression that can compromise pulmonary function.

Dialysis-associated amyloidosis

Dialysis-related arthropathy represents a major complication of uremic patients treated by hemodialysis or other renal replacement therapies. Nearly 10 years ago, this syndrome was shown to be associated with a new type of amyloid, mainly composed of beta-2 microglobulin (beta 2-M). Retention of the beta 2-M protein due to chronic renal failure, although unquestionably a prerequisite for the occurrence of beta 2-M amyloidosis, appears not to be the unique pathogenetic factor involved in this complication. A role has also been attributed to an enhanced local or systemic generation of inflammatory mediators, an increased production of beta 2-M, and an altered metabolism of the molecule including partial proteolysis and glycation. It is possible that factors related to renal replacement therapy such as dialysis membrane biocompatibility also play a role. However, the clarification of the precise underlying mechanism(s) awaits further study. Because dialysis technology has progressed considerably during the last decade, a significant beta 2-M removal can be achieved at present using high-flux dialyzers. Moreover, a marked reduction in bioincompatibility during the dialysis procedure as manifested by activation of complement and stimulation of mononuclear blood cells can now be attained. Future studies will tell whether technical progress in dialysis technique results in a decrease in the incidence of symptomatic dialysis-associated amyloidosis.

The so-called calcifying epithelial odontogenic tumour in dogs and cats (amyloid-producing odontogenic tumour)

This paper describes the microscopical features of a rare odontogenic tumour that occurs in dogs and cats and which has been referred to as the calcifying epithelial odontogenic tumour (CEOT), although it is not the counterpart of the human tumour of that name. We have proposed amyloid-producing odontogenic tumour (APOT) as an appropriate alternative term. The tumour is composed of irregularly shaped strands of squamous epithelium, which in some areas exhibit palisading of the basal cells, similar to that seen in ameloblastomas. Stellate reticulum occurs focally in some examples. The second prominent feature is the presence of amyloid which tends to calcify. Finally, in some examples, a collagenous matrix, which is apparently a form of dentine, is present focally, adjacent to the epithelium. These histological features are compared with those of the canine keratinizing ameloblastoma and the human CEOT. To date, to few examples have been reported to determine accurately the biological behaviour of APOTs, but some have recurred after excision; none has metastasized.

Amyloid deposition in the digestive tract in casein-induced experimental amyloidosis in mice

In mice with casein-induced experimental amyloidosis, the incidence of amyloidosis in various organs was examined in relation to time, and the extent of amyloid deposition in the digestive tract was investigated. Amyloid was deposited first in the spleen, a little later in the digestive tract, and then in the liver and kidney. In the digestive tract, amyloid appeared simultaneously in the small and large intestine, and later in the glandular stomach. Amyloid deposition was most severe in the ileum, while it was not induced in the esophagus or non-glandular stomach. Initially, amyloid deposition was observed along the small blood vessels and/or epithelial basement membranes in the lamina propria mucosa (LPM); it then extended to the stroma in the LPM. Amyloid deposition in each portion of the digestive tract had characteristic patterns in the LPM. Deposition of amyloid fibrils was confirmed by electron microscopy. The results suggest that the gastrointestinal biopsy used widely to diagnose human reactive amyloidosis is a sensitive early indicator of amyloidosis.

Amyloidosis

The biochemistry of amyloidosis as it relates to clinical medicine and experimental pathology is presented. Amyloidoses are complex disorders in which normally soluble precursors undergo pathological conformational changes and polymerize as insoluble fibrils with the beta-pleated sheet conformation. Over the past 20 years, 16 biochemically diverse proteins have been identified as fibrillar constituents of amyloid deposits; in all cases the protein-protein interactions that result in amyloid fibril formation appear to be stabilized both by the structure and the microenvironment of the precursor protein. Either genetic predisposition or dysfunctions of the immune system favor amyloid fibril formation. In particular, macrophage function is a factor in the pathogenesis of many of the amyloidoses. The diagnosis of amyloidosis involves acquisition of a tissue biopsy, staining of the specimen with Congo red, and observation of classic green birefringence on polarization microscopy. The subdiagnosis of the systemic amyloidoses involves characterization of variant or monoclonal plasma amyloid precursor proteins in the context of clinical symptoms. Treatment is generally supportive, with the use of antiinflammatory therapy, dialysis, or transplantation and genetic counseling where indicated.

Amyloidoma of the gasserian ganglion as a cause of symptomatic neuralgia of the trigeminal nerve: report of three cases

Three cases of symptomatic neuralgia of the trigeminal nerve due to an amyloidoma in the gasserian ganglion are described. The correct diagnosis was not made prior to histological examination of the surgical biopsy specimens. Medical history and clinical observation led to the diagnosis of a malignant process of the nasal cavities in the first patient; of an inflammatory dental focus in the second patient; and of multiple sclerosis in the third patient. CT findings were normal in cases 1 and 2; in case 3, a schwannoma was suspected from the CT appearances. In case 1, MRI had not been performed; in cases 2 and 3, MRI revealed a tumour mass which was also considered to be a schwannoma. Histologically, the tumours consisted of masses of amyloid deposits which had largely replaced the pre-existing ganglionic cells and satellite cells. Electron microscopy confirmed the fibrillar structure of the deposits. Immunohistochemistry and immunocytochemistry revealed the amyloid to belong to the AL-lambda subtype.

Spheroidal keratopathy associated with subepithelial corneal amyloidosis. A clinicopathologic case report and a proposed new classification for spheroidal keratopathy

PURPOSE

An unusual case of primary spheroidal degeneration associated with subepithelial corneal amyloidosis is described clinically and histopathologically, and a new classification for spheroidal keratopathy is proposed.

METHODS

The corneal button obtained by lamellar keratoplasty was examined by light and transmission electron microscopy. Amyloid deposits were evaluated further by means of the thioflavin T fluorescence technique, the potassium permanganate reaction, and immunohistochemical studies using antibodies against immunoglobulin light chains and proteins AA and AP.

RESULTS

Spheroidal droplets were observed in basement membrane, Bowman's layer, and anterior stroma, and exhibited characteristic staining with Verhoeff's iron hematoxylin. Amyloid deposits were found beneath the epithelium, almost exclusively in the central area of the corneal button. The deposits showed no immunohistochemical staining with antibodies to amyloid proteins AA and AP or kappa and lambda light chains.

CONCLUSIONS

The histochemical properties of the spheroidal droplets in this case were similar to those observed by other authors and suggested a sulfur-rich protein other than keratin. The combination of clinical and pathologic findings permitted the differential diagnosis of subepithelial amyloidosis and distinguished this condition from that of gelatinous drop-like dystrophy. To the authors' knowledge, this is the first description of primary spheroidal keratopathy associated with secondary subepithelial corneal amyloidosis in an eye that had not undergone previous keratoplasty.

Aqueous outflow system in familial amyloidotic polyneuropathy, Portuguese type

Familial amyloidotic polyneuropathy (FAP) is a hereditary disease which may present a wide range of ocular manifestations. Glaucoma is amongst the most serious complications of FAP. We report the results of ultrastructural study of the trabecular meshwork in a glaucomatous patient with the Portuguese form of FAP. This study showed that there was marked anatomical disruption of the uveoscleral, cornoscleral meshworks and juxtacanalicular tissue characterized by (a) accumulation of amyloid fibrils in the intertrabecular spaces; (b) degeneration of the endothelial cells; (c) homogeneous and/or multilayered plaques of basement membrane-like material loading the intertrabecular spaces or protruding to the lumen of the Schlemm's canal; and (d) degeneration of unmyelinated nerve fibres. These morphological changes and an analysis of the literature suggest that mechanical and neuropathic events can be co-existing factors which enhance the resistance to aqueous humour outflow, leading to increased intraocular pressure and glaucoma in the Portuguese form of FAP.

Giant collagen plaques in Creutzfeld-Jakob disease. Report of two cases with ultrastructural studies

We report two cases of Creutzfeld-Jakob disease with clusters of giant collagen fibers. To our knowledge, these abnormally large collagen fibers have never been described in patients with degenerative diseases of the central nervous system. The significance of the formation of such plaque-like large collagen fibers has as yet not been elucidated. It is felt that these represent a product of the degenerative process.

Amyloidosis in the upper aerodigestive tracts

The upper aerodigestive tracts, particularly the larynx, are not uncommon repositories for amyloid. In most instances amyloidosis of the larynx is localized and is not associated with or followed by systemic disease. Oral and nasopharyngeal amyloidoses, on the other hand, are very often manifestations of systemic predisposing disorders. Laryngeal amyloidosis is treated, when indicated, by surgical removal, often repeated because of persistence or multifocal deposits.

Organ-limited laryngeal amyloid deposits: clinical, morphological, and immunohistochemical results of five cases

Five cases of organ-limited laryngeal amyloid deposits with no evidence of systemic disease are reported in detail and classified immunohistochemically. In four of the five cases the amyloid reacted with anti-A lambda antibodies and in one case with anti-A kappa antibodies. Four of our five female patients had already passed the fifth decade of life. One was 11 years old. Hoarseness was the predominant symptom in four cases, in which we found amyloid deposits in the glottic area. Only one patient, with amyloid deposits in the aryepiglottic fold, complained of pain. The therapy of choice of idiopathic, localized, or organ-limited amyloid deposits without underlying disease may be local excision. In one of the cases reported in this paper, a laryngofissure was performed, and in another a partial laser resection was performed. No therapy was performed in three of our five cases. In the larynx, as in many other locations and only if possible, removal at intervals is more feasible than radical resection, because these amyloid tumors grow slowly.

Electronmicroscopic observation of amyloid deposits in the vascular walls of the choroid plexus in systemic amyloidosis

This report concerns an ultrastructural study of the vessels of the choroid plexus in 3 cases of systemic amyloidosis, sections of formalin-fixed brains being used. Small-sized arteries and arterioles were mainly affected by deposition of amyloid fibrils. In the arterioles, the amyloid fibrils were often so densely accumulated that they separated individual smooth muscle cells of the media and reached the subendothelial region. The basal surface of the endothelium of such vessels showed frequent invaginations filled with amyloid tufts; some of the tufts displaced the thin cytoplasm of the endothelial cells toward the lumen. Occasionally, tufts of amyloid fibrils were found to be exposed to and to float in the vascular lumen. These observations were made only in severely amyloid-laden vessels. Among the several possibilities regarding the tuft-endothelial relationship, the transendothelial transport of amyloid tufts is most likely, but the possibility of intraendothelial processing of amyloid precursor proteins and their secretion to form fibrils extracellularly cannot be excluded.

Skull base amyloidoma. Case report

A mass lesion of amyloid involving the central nervous system is a rare finding. A 64-year-old woman presented with a large amyloidoma at the skull base causing neural tissue compression. The only accompanying disease was an asymptomatic renal cyst. The mass had caused destruction of the bone elements and pathological calcification as seen on x-ray films, computerized tomography (CT) scans, and magnetic resonance (MR) images, and was enhanced after injection of contrast medium on both CT scans and MR imaging.

Xanthogranulomatous pyelonephritis and systemic amyloidosis: report of 2 new cases and the natural history of this association

The association of xanthogranulomatous pyelonephritis and systemic amyloidosis is extremely rare. To our knowledge, despite innumerable cases of xanthogranulomatous pyelonephritis reported in the literature, this association has been described on only 2 occasions. Clinical, analytical and radiographic findings can be highly suggestive of the diagnosis. We report on 2 patients with xanthogranulomatous pyelonephritis, systemic amyloidosis and the nephrotic syndrome: 1 died 4 1/2 years after diagnosis and 1 was stable with good general health 3 years after diagnosis. The clinical aspects as well as the treatment given to both patients are discussed. We describe the natural history of an association that due to its rarity is not currently well known.