If examining tissue sometimes seems akin to looking for the proverbial needle
in a haystack, then trying to identify amyloidosis can make pathologists feel
like they’re looking through every field of hay in the Great Plains. On
foot. Amyloidosis is that hard to find.
Or is it? Maybe the real problem of finding a needle in a haystack is that
no one actually ever looks for one. The task sounds impossible, so why begin?
A small but vocal number of pathologists, clinicians, and patients, however,
are urging physicians to start looking for amyloidosis, suggesting they may
be surprised by what they find.
No one is saying the disease isn’t rare, because it is. But they contend
it may not be as rare as previously thought, and that misdiagnosis and underdiagnosis
may be warping perceptions. Moreover, failing to make a correct diagnosis causes
unconscionable harm—costly and damaging procedures, failure to treat,
and early death. It’s time, they say, to take a fresh look at amyloidosis.
For many physicians, the first—and sometimes only—look comes
in medical school, where they’re shown the most obvious presentation
of the disease and told that amyloid is rare, that no treatment exists,
and that they’ll never see a case anyway. Listen to the experts,
however, and it quickly becomes obvious such views are as outdated as
“These are misconceptions that have been carried over from 15,
20 years ago,” says Morie Gertz, MD, chair, Division of Hematology,
Mayo Clinic, and professor of medicine, Mayo Clinic College of Medicine.
“It’s wrong to say there’s nothing to be done. There’s
actually a lot to be done.”
But old attitudes die hard. Dr. Gertz tells the story of being approached by
a cardiologist at a recent meeting, who asked him, “Well, does it make
a difference if we make the diagnosis or not? There’s no treatment.”
Mayo is considered to be one of the two major amyloidosis centers in the United
States—the other is at Boston University—and it treats virtually
all its patients, according to Dr. Gertz. He and his colleagues have, in fact,
found many needles, in many haystacks.
So have Muriel Finkel and Elinda Lado. Finkel is president of the Amyloidosis
Support Groups, and Lado is secretary of the ASG and a facilitator of the support
group in Philadelphia. Both see patients who’ve been misdiagnosed for
years, who’ve been given inappropriate treatments, who’ve had unnecessary
surgeries, and who’ve died mere weeks after being given the correct diagnosis.
Based on the experiences of the people in their support groups, they say it
takes physicians from one to five years to arrive at a correct diagnosis.
Lado’s husband, a surgeon, has amyloidosis, and now receives regular
care at Mayo. He found it easy to ignore one early sign of trouble—carpal
tunnel syndrome—because of his occupation. Later on, his cardiologist
suggested trying a heart medication “just to see what would happen,”
says his wife, her voice still registering disbelief. It took three biopsies—and
a persistent physician insisting that amyloid was present—before the correct
diagnosis was made.
Clinicians and patients put pathologists at the frontlines. Lado estimates
that among members of her support group, at least 25 percent were given the
correct diagnosis only after the pathologist became suspicious for the disease
and decided to look for it. “Their cardiologist was scratching his head,
or their GI guy was scratching his head. It was the pathologist who was astute
enough to take the sample and Congo red stain it,” Lado says.
It might be convenient to dismiss the strong, often angry words of patients
as mere anecdotes if they weren’t so frequently echoed by leading amyloid
specialists. “If the pathologist is waiting for clinical information suspecting
amyloid, they’ll miss the majority of patients,” says Dr. Gertz.
“It often takes visits to a few different physicians before the biopsy
is ultimately done,” says Carl J. O’Hara, MD, chief of surgical
pathology, Boston Medical Center Pathology Department, and associate professor
of pathology, Boston University School of Medicine. In other cases, he says,
diagnoses aren’t made until an affected organ begins to fail.
No one is faulting physicians for what they were taught years ago, or for what
they may or may not remember from those lessons. But there’s plenty new
to be learned.
The field has changed immensely in recent decades, says Dr. Gertz. The understanding
of the biochemistry of amyloid has improved, and technically it’s much
easier than in the past to classify the subunit protein that’s responsible
for the intact amyloid fibril. There are new techniques that allow physicians
to classify amyloid and monitor therapy. And with the introduction of new agents,
as well as with transplants, physicians have unprecedented ability to treat
many types of amyloidosis, extending life and improving organ function tremendously.
All that is for naught if the correct diagnosis isn’t made to begin
with. And according to many, it often isn’t.
“Diagnosis is still made too late,” says Dr. Gertz.
Physicians falter in any number of ways. Making the diagnosis first requires
a level of suspicion. But few consider it, given how rare the disease is. “It’s
still pretty uncommon,” Dr. Gertz concedes, before adding, “But
just because it’s esoteric doesnmean it lets physicians off the hook.”
The simplest solution—keep amyloidosis in the back of your mind—is
harder than it sounds. “The symptoms are so vague, it’s a wonder
that any of us would ever think of it,” says Martha Skinner, MD, director
of the Amyloid Treatment and Research Program at BU and professor of medicine
at Boston University.
Dr. Skinner suggests amyloid is underdiagnosed because its symptoms mimic those
of many other diseases. Shortness of breath usually points to heart disease.
“You don’t think amyloid at that point,” she says. “And
protein in the urine points to kidney disease, but you don’t think of
amyloid.” The only point-blank symptom is macroglossia; otherwise, she
says, no one clinical finding would make a clinician think, This is amyloid.
Finkel points to her late uncle as a classic case. For years, she says,
he’d complain of arthritis in his back; the real problem was in
his kidneys, which were affected by amyloid deposits. Her uncle also had
gastrointestinal problems (constipation and diarrhea are common among
patients with amyloidosis) and had his gallbladder removed—unnecessarily,
as it turns out. (Finkel says she later posted a question on her association’s
600-member listserv asking them about gallbladder-related issues. “You
would be amazed at the response I got,” she says. “It appears
that everyone at one time or another was diagnosed with gallbladder problems”
before a diagnosis of amyloid was made.)
If clinicians aren’t thinking about amyloidosis, can pathologists
raise the index of suspicion?
Dr. O’Hara says, “The clinical presentation is so diverse
and so varied, that when I give the lectures to the medical students at
BU, I jokingly say to them that anytime anybody asks them for a differential
diagnosis, just throw in amyloid, because theyprobably be right.”
Guillermo A. Herrera, MD, chairman of the Department of Pathology and professor
of pathology, cellular biology and anatomy, and medicine, LSU Health Services
Center, Shreveport, echoes Finkel and Lado when he says that it’s not
unusual for pathologists to make the call even before the clinician is considering
When clinicians ask pathologists to rule out amyloid, he continues, the
matter is more straightforward, and such a request usually results in
the proper stains being done. “It is when nobody’s suspecting
it that the pathologist gets into trouble,” he says.
Otherwise, says Maria M. Picken, MD, PhD, most pathologists consider
amyloid only when they see obvious deposits of homogenous material, which
indicates advanced disease. “It’s important to think about
amyloid not only when you look at the H&E and it looks ‘suspicious,’
but deposits can be very subtle, and we should be striving to catch it
early on,” says Dr. Picken, director, renal pathology and electron
microscopy laboratory, and professor of pathology, Loyola University Medical
Center, Maywood, Ill.
Dr. Picken says that when she makes a diagnosis of amyloid, she reviews
previous biopsies when they’re available. “Quite frequently
I do detect amyloid in prior biopsies,” she says.
In her mind, it’s rarely a question of, How did they miss this?
“It can be very subtle, and I don’t want to throw stones at
pathologists,” Dr. Picken says. But it happens often enough that
she questions whether pathologists consider amyloidosis as often as they
Amyloidosis is entangled in several Catch-22s. It’s rare, so physicians
may not bother to look for it; if they’re not looking, they may not see
it; if they do look, it may go unseen because they’re inexperienced in
detection techniques; they lack that experience because the disease is rare.
If there’s one thing everyone does know about amyloidosis, it’s
the Congo red stain. This stain usually suffices in the simplest scenario, when
there’s plenty of amyloid present, indicated by the telltale apple-green
birefringence. Positive and negative controls are important. False-positives
often occur from overstaining collagen, which is birefringent on its own. Nor
should pathologists make the diagnosis of amyloid based on the presence or absence
of salmon-pink color, which is seen in bright light. Instead, the tissue needs
to be polarized, which “is not something that many pathologists are immediately
familiar with,” Dr. Picken says.
Pathologists often use a homemade substitute—two sheets of film—to
cross-polarize tissue. “As you can imagine, the sensitivity of this sort
of setup is very low,” Dr. Picken says. She also makes the point that
reading Congo red requires very strong light. “You need to turn the light
source to the max, and to see small deposits you should read it in the dark,”
a step she says is not routinely taken.
Dr. Picken suggests that in some cases, pathologists might want to reconsider
how cost fits into the equation. “People don’t think twice about
upgrading their computers. But yet I still see many pathologists working with
outdated equipment, which they get used to using and they don’t think
much about upgrading,” she says.
Merrill Benson, MD, sees a similar penny-wise, pound-foolish reasoning at play.
“For some reason or other, they spend a few thousand dollars for a microscope
and refuse to pay another hundred dollars for a set of polarizers,” says
Dr. Benson, professor, Department of Pathology and Laboratory Medicine, Indiana
University School of Medicine.
When asked what pathologists do instead of using polarizers, Dr. Benson says,
“They miss things.” In her department, Dr. Picken has become the
de facto amyloid expert and reads all the Congo red stains. Reading Congo red
isn’t hard—“but there is some how-to involved,” as she
puts it. “If one is not quite familiar with interpretation, it is quite
all right to send it out or to ask somebody to verify it” at an academic
or larger hospital laboratory.
Dr. Herrera insists that even small labs should become comfortable using Congo
red stains and polarizing tissue. “Remember, in some cases, they are going
to have to be the ones to pick it up. So they’re going to have to identify
that something is suspicious, and they’re going to have to have available
to them a good way to rule it in or rule it out. Otherwise, they will be making
Almost any pathologist should be able to identify amyloid in larger deposits,
he continues. Small quantities and slight differences in tincture are problematic.
“That’s when they either ignore it or consider it to be something
Few laboratorians are getting the practice they need to become proficient,
Dr. Herrera contends. “Histotechs don’t do amyloid stains every
day, and they may not perform the stain the way they should,” he says.
In a typical 150- to 200-bed community hospital, amyloid stains may be done
10 times a year, if that. And most of those are rule-out situations.
A generic diagnosis of amyloid needs to be followed by typing. “People
say that typing amyloid is difficult, that there are a lot of false-negatives
and false-positives,” Dr. Picken says. “And I would agree that typing
amyloid does require a certain degree of expertise. It’s not easy. But
it can be done. It should be done. After making a generic diagnosis of amyloid,
we need to go further.”
Many pathologists still need to be convinced. “As far as amyloid
is concerned, people tend to think that this is something you write down
in the diagnosis field,” says Dr. Picken, “and then you may
not see any subsequent specimens from these patients. It just sort of
disappears” for the pathologist, she says, who assumes the patient
does poorly or dies, “end of story.”
Adds Dr. Herrera: “They think, ‘Once we call it amyloid,
we have done our job, and from there on we don’t need to worry about
anything else.’ And that is not true.”
Typing is typically done using immunofluorescence and immunohistochemical techniques.
Pathologists need to use a panel of antibodies, which typically would include
a stain for amyloid P component, which is present in all types of amyloid regardless
of the nature of the fibril protein itself.
With renal biopsies, says Dr. Herrera, typing begins with fluorescent staining
for kappa and lambda light chains. If the renal biopsy is neither kappa- nor
lambda-positive, pathologists need to “look at your heavy chains very
carefully.” Heavy chain associated amyloidosis—either IGG or IGM—was
first described in 1993. If those are negative, other options include using
antibodies to AA and to fibrinogen.
Most amyloid cases turn out to be AL amyloid, and most of those are lambda
light chain related. “Just excluding light chain amyloidosis and AA, you’re
going to diagnose 95-plus percent of cases,” says Dr. Herrera. “The
hereditary types and the other types are very rare.”
It’s easier to pick up early cases of amyloid in renal biopsies than
in other organs, even when there’s no clinical suspicion. “It doesn’t
take much amyloid in the kidney to result in significant proteinuria,”
explains Steph en Bonsib, MD, director of surgical pa thol ogy, Indiana University.
And standard special stains for the kidney, particularly the silver stain, will
usually reveal amyloid deposits even in small amounts. Experienced observers
using electron microscopy can easily recognize even small quantities of amyloid.
Silver stain in patients with amyloid shows a distinctive appearance, says
Dr. Bonsib. That in itself doesn’t prove amyloid, because other diseases
can stain in similar fashions. But it raises a red flag, he says, “and
amyloid will usually crop in as a possibility.”
In some cases, amyloid on the silver stain is completely negative, Dr.
Bonsib continues. “There are not very many things that accumulate
in the kidney that are silver negative.” Sometimes amyloid has a
distinctive organizational pattern—rather than being randomly arrayed
(the most common pattern), they’re parallel arrayed. “Then
they have an affinity for silver stain.”
The best method of identifying the fibrils may be to extract the amyloid
and do amino acid sequencing to identify the responsible protein. The
downside, of course, is this approach is extremely labor-intensive and
requires instrumentation that most laboratories don’t have.
That leaves pathologists with either IHC or a panel of antibodies directed
against various fibrils. Immunofluorescence is best done on frozen tissue, so
it’s often used by renal pathologists. “That has been reasonably
successful in terms of identifying the fibril,” says Dr. O’Hara.
“I had a conversation with my colleague across town, who is a renal pathologist.
In his hands, he feels that he can successfully identify the fibril in most
of the cases. That said, however, I happened to see a paper that was written
last year from a group in Alabama reporting that in 12 of 34 patients (35 percent)
with proven AL amyloidosis there was negative immunofluorescence staining for
kappa and lambda light chains” (Novak L, et al. Nephrol Dial Transplant.
At Boston, Dr. O’Hara and his colleagues identify fibrils by IHC, which
is “not without its nuances,” he says. “There is usually a
problem with background staining, which is most likely due to the increased
sensitivity of the primary antibodies in detecting kappa/lambda light chain
immunoglobulins, AA, or trans thyretin, etc., using very sensitive detection
systems.” It makes sense, he says—the antigens of interest are present
normally in tissues, and the primary antibodies used in IHC cannot distinguish
these normal antigens from those present in the amyloid deposits. Dr. O’Hara
and his colleagues use blocking and antigen retrieval methods to counteract
this problem, with reasonable success. “The frustrating part is that one
can run a case one day and have it work out fine but on another case the amyloid
is positive for all the antibodies tested. These latter cases obviously have
to be viewed as inconclusive and we have to resort to something else.”
That “something else” is a modification called immuno electron
microscopy, or immunogold. This procedure uses antisera tagged with gold
particles to localize antigens at an ultrastructural level—in this
case the extracellular fibrils of amyloid, Dr. O’Hara explains.
For reasons perhaps related to the fixation and to the various cleansing
steps in between, the background problem is reduced. The downside, however,
is that it’s labor-intensive. Dr. O’Hara and his colleagues
are working with a modified version of the method, adapted to light microscopy.
“That’s in its very early stages, so I can’t really
comment much more on it,” he says. “But it appears that it
might offer us another modality. The downside again is that you need to
know about it upfront to fix the tissue appropriately. Unfortunately for
cases that are submitted in consultation or for confirmation of the diagnosis,
already fixed and embedded in paraffin, it is not as useful.”
If typing seems beyond the reach of most laboratories, the initial steps
of identifying amyloid certainly are not.
First, think about amyloidosis as a possible differential. That should
be second nature for renal pathologists, says Dr. Picken. But other pathologists
should keep it in mind, too. “It may not be the No. 1 differential,
but there is room for asking, Could this be amyloid? Especially if something
doesn’t fit. And I think the fact that the clinician doesn’t
tell us [the history] doesn’t excuse us from asking the clinician.”
Dr. Picken and others suggest pathologists should be doing Congo red stains
much more readily, starting with kidney and older patients who have otherwise
unexplained proteinuria or renal failure. Within the GI tract, Dr. Picken says,
“I’ve seen patients with little erosions and ulcers, and diagnosis
of collagenous colitis and ischemic colitis is frequently made in patients with
Dr. O’Hara recommends taking a closer look at tissue removed from patients
with the carpal tunnel syndrome. “Periodically we’ll come across
ones where we say, Geez, that looks awfully funny-looking, maybe we should get
some stains. And lo and behold, it turns out to be amyloid.”
Taking a step back, Dr. O’Hara notes the first clue to amyloid
can pop up even earlier. “It’s all well and good to talk about
the Congo red stain, but ordinarily that’s the second line. The
first line of identification really is on the H&E or the PAS stain.
That’s where we become aware of this amorphous deposit and should
be highly suspicious is amyloid. That’s where it all begins. Obviously
if you don’t think it’s amyloid, then you’re not going
to order the stains that would help you support the diagnosis.”
U.S. physicians typically think about underlying plasma cell dyscrasia/multiple
myeloma, because it’s the most frequent type of amyloid in this
country, says Dr. Picken. But AA amyloid, typically associated with chronic
inflammatory states, can be diagnosed in younger patients. “We tend
to forget that younger patients may also have amyloid,” she says.
Dr. Benson says that as a baseline, physicians need to think about amyloidosis
in any patient who develops kidney problem, kidney failure, or proteinuria
and who has a history of chronic inflammatory disease. A growing number
of patients infected with HIV are developing a Castleman’s-type
syndrome, he adds, which is a reactive lymphadenitis and which can cause
There’s also chronic joint disease, rheumatoid arthritis, spondyloarthropathy,
and the ever-expanding group of familial periodic fevers and related disorders.
Included in this latter group are conditions like Crohn’s disease
and sarcoidosis. Patients with any of these diseases may develop AA amyloid,
says Dr. Picken.
Familial amyloidosis is drawing a fresh look. Some 20 years ago, it was reported
that only two percent of amyloid patients were affected by a hereditary form
of the disease; more recent data, from Boston, suggest it affects perhaps 10
percent of patients. Another study, from the U.K., showed that some 10 percent
of patients who were suspected of having amyloid derived from the immunoglobulin
light chain, that is, AL amyloid, were subsequently found to have familial amyloidosis.
“The most striking feature was that these patients did not have any family
history. So we need to rethink our approach,” says Dr. Picken. “And
of course we may be dealing with a de novo mutation.”
A clinical history that includes organ system disease in more than one organ
should prompt clinicians to think about amyloid, says Dr. Skinner. And if clinical
history is available, it could prompt pathologists too—but the history
is likely to be lacking. Teresa McHale, MD, is hardly unique when she talks
about the dearth of clinical information to accompany biopsy material. “You’d
be amazed at the things you find out about patients that the clinicians didn’t
put on the requisition,” says Dr. McHale, assistant professor, University
of Pittsburgh Medical Center. “So talking to clinicians about the possibility
of amyloid might help to pull the clinical picture together.”
For years, says Dr. Herrera, the standard take on amyloid was that it
was unimportant. “It was seen as waste material, and nothing happened
as a consequence of it,” he says. But the last 15 or so years have
revolutionized the field.
One new realization is that amyloid is not just one disease, but several—each
with its own treatment and prognosis. Some 20-plus different protein types
can make amyloid.
Dr. Benson notes that there are also other protein deposition diseases, “which
sort of are amyloid wan na bes,” such as Huntington’s and Parkinson’s
diseases. “So the field has expanded to be called protein-folding diseases.
Our journal, which was called Amyloid, is now called, Amyloid—the journal
of protein-folding diseases.” All these diseases likely share pathogenic
mechanisms, says Dr. Benson, but each is a different disease. “And we
now define them by their proteins and not by the old terms of primary, secondary,
hereditary, or whatever. So secondary amyloid is now AA, or amyloid A.”
There’s also been growing discussion about a pre-amyloidotic state,
or silent deposits of amyloid. “What it means in the long run is
not altogether clear, and even our working definition of amyloid may change
as we learn about the condition,” says Dr. Picken.
Each new advancement would be reason for physicians to press for a clear,
detailed diagnosis, although in Dr. Benson’s view, a more basic
reason should be compelling enough. “I’m a real believer in
making a correct diagnosis and pursuing a diagnosis, and it really bothers
me when a doctor says, ‘Well, will it make any difference if we
make the diagnosis?’ To them perhaps not,” he says. “To
me it would.” And for patients, most definitely.
Karen Titus is CAP TODAY contributing editor and co-managing editor.