Lymphedema

Lymphedema is the pathologic accumulation of fluid in the soft tissues as the result of impaired lymphatic drainage, with resultant inflammation, adipose tissue hypertrophy, and fibrosis. It can be either primary or secondary, due to surgery or disease processes. The condition can cause disfigurement due to regional swelling and induration. Treatment can prove difficult in many instances.

Most cases of primary lymphedema are sporadic; the rest are either hereditary or associated with other congenital conditions (see below).

There has been growing prevalence of secondary lymphedema in recent years due to the large number of patients undergoing breast and pelvic surgery and/or receiving radiation therapy; so much so, in fact, that in the developed world, secondary lymphedema due to iatrogenic causes constitutes the majority of cases.

Lymphedema occurs from the accumulation of interstitial and lymphatic fluid within the skin and subcutaneous tissue. This then stimulates fibroblasts, keratinocytes and adipocytes which in turn result in deposition of collagen and glycosaminoglycans within the skin and subcutaneous tissue which could then lead to skin hypertrophy and destruction of elastic fibres.

It has traditionally been defined as interstitial oedema and protein accumulation due to a defect in the lymphatic drainage. More recent findings suggest that the interstitial protein concentration may be low in some types of lymphoedema.

Lymphedema is broadly classified into primary and secondary forms.

Due to an inherent defect in the lymphatic vessels or lymph nodes.

Primary lymphedema can be further classified clinically and lymphangiographically (for the latter, see Radiographic features below).

Clinical classification is based on the age of onset:

  • congenital lymphedema: onset within 2 years of birth (comprises 6-12% of all primary forms) 7,8
    • autosomal dominant: Milroy disease
    • familial, non-dominant
    • sporadic: most common
  • lymphedema praecox: manifests between ages 2-35 (77-94%), much more common in females (female to male ratio of 10:1)
    • autosomal recessive: Meige disease
    • sporadic: much more common
  • lymphedema tarda: manifests after age 35 (11%)

Arises from obstruction or disruption of the lymphatic system, either to the lymph nodes or to the lymphatic channels

Diagnosis is usually a straightforward clinical one in advanced chronic disease, though imaging is utilised for confirming the diagnosis, for surgical planning, and intraoperatively. In early or intermittent disease, on the other hand, diagnosis can prove difficult.

Lymphoscintigraphy is commonly used for confirming the diagnosis of lymphedema and is a reliable method for functional assessment of the lymphatic system. It affords visualisation of the major lymphatic trunks and lymph nodes as well as evaluation of lymphatic function. 99mTc sulphur colloid radiotracer is injected into the interdigital web space of the afflicted limb, either intradermally or subdermally. Using stress tests, it is possible to quantify the rate of tracer disappearance from the injection site and its accumulation within the lymph nodes. Typical abnormalities in lymphedema include 10,11:

  • dermal backflow
  • absent or delayed radiotracer transport
  • crossover filling with retrograde backflow
  • absent or delayed lymph node visualisation

Magnetic resonance lymphography (MRL) entails the acquisition of
high-resolution 3D datasets of the entire limb. It is especially useful for preoperative planning of lymphaticovenular anastomosis (LVA) microsurgery, as it can demonstrate individual lymphatic channels and areas of dermal backflow 12.

An MR lymphography exam comprises two sequences:

  1. 3D heavily T2-weighted: shows severity and distribution of lymphedema
  2. postcontrast high-resolution fat-suppressed 3D spoiled gradient echo (SPGR) after intracutaneous contrast injection: depiction of lymphatic channels

Finally, an MR venogram (also high-resolution 3D SPGR) may also be obtained after intravenous contrast injection to further facilitate the differentiation of superficial veins from lymphatic channels.

CT can be used to localise oedema as subfascial or epifascial and depict the characteristic honeycomb pattern of subcutaneous oedema and skin thickening. Its role in follow-up is diminishing, though, owing to its inherent ionising radiation.

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Article information

rID: 35465
System: Vascular
Tag: cases
Synonyms or Alternate Spellings:
  • Lymphoedema
  • Lymphatic edema
  • Lymphatic oedema

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