The workup for a neck mass, particularly in adults, is not
as straightforward as most folks believe, prompting some to ask, “Doc, why not
remove the darn thing!” The answer:
“Well, uh, it’s more complicated than that.”
You see, a lump or bump in the neck can be a variety of
things. As mentioned in a prior post (Neck Mass: Not Every Lump Is A Tumor), there
are different structures in the neck that can be seen or felt. Some of these structures are normal and some
may be heightened variations of normal.
Of course, it could be abnormal, but before embarking on surgery, you
got to first determine the cause; you don’t want the doc to remove, say part of
your larynx, just because that particular something you noticed is actually
your Adam’s Apple (part of larynx that projects outward) or remove that
pulsating lump which could be your carotid artery—it goes without saying, you’d
have one fine, bloody mess.
Neck masses occurring in patients are not that uncommon, yet
often the underlying cause is not easily determined. Most of
the time, a mass in the neck is due to an enlarged lymph node. As such, we’ll
discuss the lymph node system of the head and neck, an exhilarating and
thrilling topic, depending on your audience, usually confined to quirky ENT
docs.
There are a variety of
causes for lymph nodes to enlarge (from here on we’ll sometimes refer to these
simply as nodes), one of which can be
cancer. In the neck, squamous cell carcinoma (SCCA) is one of
the most common cancers found. SCCA
arises from abnormal, cancerous transformation of the epithelial cells that
line the mouth, throat, nose, nasopharynx (the area behind the nose) and larynx—essentially
the moist pink tissue found covering those areas. Also, SCCA can occur anywhere on the skin of the
head, face and neck. SCCA can then spread
via tiny lymphatic channels to various lymph nodes in the neck, causing one or
more of these nodes to increase in size and giving rise to an abnormal mass in
the neck. The diagram at the beginning shows
the pathways of lymphatic drainage from their various sources to different nodes
in the head and neck.
Lymph Nodes and the
Lymphatic System
Lymph nodes are part of the immune system—the body’s defense
system--protecting you from a variety of foreign invaders. The lymphatic system consists of tiny
channels that drain virtually any surface of the body, whether it’s the outer
skin or the inner tissue lining the various orifices or entry points leading
deep into the body. These lymphatic channels
carry antigens—various proteins from viruses, bacteria, fungi or other stuff
such as allergens (pollens, animal dander, etc.) or cancer cells--and carry it
to a series of lymph nodes. The lymph
nodes use the antigen to stimulate certain white blood cells within it
(lymphocytes) to create antibodies to fight off those foreign antigens. Also, other cells (macrophages, other white
blood cells) in the nodes are stimulated to gobble up antigens. The lymph node increases in size to accommodate
all this extra activity. Think of the
lymph nodes as small factories creating defensive weapons. These weapons: antibodies and white blood
cells are then released into the blood stream to prevent the spread foreign
material from creating havoc to other bodily areas.
Once they complete their task, the nodes typically reduce
back to normal size. However, in the
case where an infection overwhelms the node, there is over-population of white
blood cells and the node continues to expand.
Many of the cells die (foreign invaders and white cells) and then
purulent liquefaction occurs, also known as pus,
and then a phenomenon called an abscess is formed, which is essentially a
collection of pus. The body tries to
wall this off, but often cannot get rid of the dead material itself, leading to
more inflammation and unpleasant things such as pain and fever and sometimes a
big mass in the neck. This then requires
surgical drainage.
Cancer cells can also invade lymph nodes. In some cases, cancerous cells growing in a
particular area, say on the skin or in the throat may spread through the
lymphatic channels and become trapped in the lymph nodes along those channels,
stimulating the cells in the node to mount a defense, just as they would with
an infection. However, sometimes the
cancer cells continue to multiple and grow, overwhelming the defenses of the
node and instead of being killed and gobbled up, they proliferate within the
node causing it to enlarge. This is
termed a metastatic lymph node. Cancer cells can then leave that node, travel
down the lymphatics to involve other nodes along the way or to distant sites in
the body.
Given the nature of lymphatics and lymph nodes, I hope you
can now imagine the importance of determining the source before whacking out
any tissue in one’s neck.
The site of node involvement can give you a clue to the
source, by working retrograde—i.e., tracing the drainage pattern backwards
along the predicted flow of lymphatics from the involved node to the source. This source is called the primary site.
Searching for the
primary site
Searching for the
primary site refers to a diligent search for the original source of the cancer. Finding the primary site is important in
order to properly treat the cancer.
Merely removing the involved nodes misses residual cancer
elsewhere. The workup is thus done in
step-wise fashion:
1. Physical Exam
The doctor does a thorough
examination. This includes carefully
examining the ears, nose, mouth and throat, and also palpating (feeling the
neck with hands). Don’t be surprised if your
doc puts a finger or two into your mouth (hopefully gloved—you may not want to
taste grubby fingers soiled with the day’s lunch or something worse) feeling
around while also pushing around your neck and jaw and face with the other
hand. Sometimes unusual areas of
firmness or mass-like findings are detected that could not be visualized.
2. Fiberoptic nasopharyngoscopy and
laryngoscopy.
Oftentimes, a fiberoptic
nasopharyngoscopy is done. This is a fancy term for placing a flexible
scope into the nose, down into the throat to visualize all those nice
structures on the way in and on the way out.
Though gruesome-sounding and very hideous when seen for the first time,
this procedure for the most part is rather painless and most people tolerate
this well. If your doc has a smidgen of
humanity, the nose and throat is first sprayed with an anesthetizing medication
to numb the tissues and a decongestant to open the nose, allowing for easier
passage of the scope. With the scope, the
doc checks out the inside of the nose, the back of the nose as it blends with
the throat (the nasopharynx) and then further down to view the oropharynx,
larynx and the hypopharynx (the entrance into the esophagus located behind the
larynx).
3. Imaging: this usually is a CT scan (Computed
Tomography) of the neck, which provides nice sectional images to determine the
extent of the neck mass, its relation to other structures in the neck, whether
other nodes are involved. Sometimes the
CT may give a clue to the primary site if it cannot be found on exam or with
the fiberoptic scope.
4. Biopsy: A biopsy is a technique whereby
various amounts of tissue are removed from the suspected mass which is then
sent out to the pathologist, who then renders a diagnosis. A needle biopsy of the mass if primary not
detected. This requires anesthetizing
the tissue over the mass and inserting a small needle into the mass to obtain
small bits of tissue. Since the
pathologist views the specimen under a microscope, a very small amount of
tissue removed in this fashion often is sufficient for a diagnosis
5. Panendoscopy (where pan- means “all”): This is a
variety of endoscopic procedures where various types of scopes are used to view
the mouth, throat, larynx, esophagus (the tube leading to the stomach) and
sometimes the trachea and bronchi (the breathing tubes the bring air to the
lungs). These are often rigid endoscopes
that look directly at tissues and are more formerly called: direct
laryngoscopy, esophagoscopy, bronchoscopy and directed biopsies of any
suspicious tissue. If nothing suspicious
is found, then biopsies are done where cancer may be hidden, namely in the area
of the tonsils, base of tongue and nasopharynx.
If the palatine tonsils are present, both are typically removed since a
small cancer can hide within the depths of the tonsil and a biopsy can easily
miss this.
6. Open biopsy or removal of the mass/node. This is the last resort. If the prior needle biopsy was not diagnostic
or if there is suspicion for lymphoma (a type of cancer that originates in
lymph nodes), then removal of the node is required and sent immediately to the
pathologist who examines it with a technique called frozen section pathology. A panendoscopy usually is scheduled at the
same time. If SCCA is noted on frozen
section pathology, then we proceed with a panendoscopy to search for the
primary. If something else is noted such
as lymphoma, then no further procedures are done, since treatment for this is
typically medical, and not with further surgery.
6. PET CT (Positron Emission Tomography with
CT):
This is an imaging
technique that helps to identify the primary site as well as any other sites in
the body that might be involved, such as other lymph nodes or within other
organs such as the liver, bone, brain, etc.
This modality uses radiolabeled glucose molecules known as FDG
(fluorodeoxyglucose). Glucose is the
common simple sugar your body uses for energy.
Malignant cancers tend to be hyper-metabolic—meaning they’ll consume
glucose faster than normal bodily tissues. The FDG will thus accumulate more readily in
tissues invaded with cancer cells and light up on the PET CT. Thus, imaging with this technique may help
identify the primary site as well as other lymph nodes in or beyond the neck.
This was not meant to
be an exhaustive coverage on this topic, but to hopefully shed some light on the
rationale behind the workup of a neck mass suspicious for cancer. Though receiving a diagnosis of cancer is
devastating, don’t despair. Treatment--via
a variety of modalities including radiation therapy, chemotherapy and surgery--is
potentially curative in most people, many of whom lead productive, high-quality
lives afterwards.
©Randall S. Fong, M.D.
www.randallfong.com
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