lymphangioma as hamartomatous, (harmartomas
are benign tumors) which refers to the lesion’s pat-
tern of self-limiting growth. Lymphangiomas are
congenital or arise soon after birth, most commonly
manifesting as SKINlesions on the head, back, arms,
and legs, though the lesions may involve any exter-
nal or internal epithelial tissue (skin and mucous
membranes). Lymphangiomas grow slowly, then
stop growing and remain the same size. Though not
cancerous, a lymphangioma may cause problems or
symptoms because of its location and size. A lym-
phangioma in the SMALL INTESTINE, for example, may
interfere with the absorption of NUTRIENTSor create
an ILEUS(obstruction).
Lymphangiomas that do not cause symptoms
do not require treatment as they are self-limiting.
A surgeon can operate to remove a lymphangioma
that causes symptoms or is cosmetically unsatis-
factory. However, the structure of a lymphan-
gioma has no capsule and tends to diffusely
infiltrate tissue, making it difficult for the surgeon
to remove it completely. If the lymphangioma has
not finished growing, it will recur. Most lymphan-
giomas are benign in that they do not cause symp-
toms or health problems.
See also BIRTHMARK; HEMANGIOMA.
lymphedema Swelling and often discomfort aris-
ing from inadequate LY M P Hdrainage and flow that
allows interstitial fluid (fluid between the cells) to
accumulate. Lymphedema most often occurs
when INFECTIONor CANCERthat extensively engages
the lymphatic system, or when surgery disrupts
the LYMPH VESSELSand lymph nodes. Lymphedema
is a common consequence of surgery and RADIA-
TION THERAPYas treatments for cancer. Surgeons
typically remove adjacent or sentinel lymph
nodes, which are most likely to be affected by the
cancer, during surgery to remove cancerous
tumors to determine the extent to which the can-
cer has penetrated the tissues or metastasized
(spread) to other tissues. Lymphedema can be
debilitating when the swelling becomes substan-
tial. Recurrent, progressive lymphedema often
develops into fibrosclerosis (scarring and harden-
ing) of the involved tissues.
It is important to distinguish lymphedema from
other causes of swelling, such as edema (simple
fluid retention) and ASCITES, because though the
appearance of the affected area may be similar the
treatment approaches differ. In chronic lym-
phedema the SKINover the swollen area acquires a
characteristic “orange peel” texture, which indi-
cates damage to the underlying tissue. Tissue in
the damaged area becomes susceptible to infection
and ulceration, as the lymphedema compromises
its BLOODcirculation and immune response. While
conventional edema improves with diuretic med-
ications, lymphedema does not.
For lymphedema, treatment focuses on
improving the flow of fluid into and through the
lymph vessels. Compression sleeves and stockings
provide gentle, consistent pressure against the
affected arm or leg, helping prevent interstitial
fluid from accumulating. Some people with severe
lymphedema benefit from compression pump
therapy, in which a pump gently inflates and
deflates pressure cuffs wrapped around the arms
or legs, to help squeeze interstitial fluid into the
lymph capillaries. Surgery to remove damaged
portions of tissue and lymphatic structures is a
treatment of end resort that may improve very
severe lymphedema when other methods have
failed, though itself can cause further or more
extensive damage.
Lymphedema is a lifelong concern for most
people who develop it, regardless of its cause
though particularly after extensive surgery that
disrupts the lymphatic structures or in which the
surgeon removes lymph nodes. Many people can
manage their symptoms and discomfort through
preventive measures such as frequent movement
or self-massage of involved areas and prompt
therapeutic response when swelling begins.
See also HEART FAILURE; LYMPH NODE; SENTINEL
LYMPH NODE DISSECTION; SURGERY BENEFIT AND RISK
ASSESSMENT.lymph node A small structure of lymphatic tis-
sue. LYMPHnodes, sometimes erroneously called
lymph glands, occur individually as well as in
beadlike strings within the tissues. The lymph
nodes range in size from that of a grain of rice to
that of a kidney bean, and appear roughly kidney
shaped.
Each lymph node contains high numbers of
lymphocytes and macrophages (tissue-resident
monocytes), which filter pathogens and cellular150 The Blood and Lymph