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8.5 · Lymphedema
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in a one- way directional path to return protein, colloids,
and particulate matter to the systemic venous circulation.
Lymphedema usually involves abnormalities in the regional
lymphatic drainage of the extremities (either upper or lower,
or both), although visceral lymphatic abnormalities can also
occur.
Lymphedema is caused by a reduction in lymphatic transport, and it can be either primary or acquired (secondary). In
primary lymphedema, several anatomic problems can exist
leading to lymphatic stasis, including lymphatic hypoplasia
and functional insu ciency, absence of lymphatic valves, or
impairment in the intrinsic contractility of the lymphangion
(the segmentally contracting, functional vascular unit of the
lymphatic circulation).
Causes of Primary Lymphedemas
1 . Congenital lymphedema ( Milroy ’ s disease ): lymphedema
that appears at birth or before 2 years of age. It is caused
by a mutation that inactivates the VEGFR3 tyrosine
kinase signaling mechanism that is felt to be speci c to
lymphatic vessels. e swelling o en involves lower
extremities, the genitalia, and even the face.
2 . Lymphedema praecox ( Meige ’ s disease ): lymphedema that
appears between 1 and 35 years of age (mostly at the time
of puberty). It is the most common form of lymphedema
(94 %), and it typically involves one limb. Most cases
involve the lower limbs, especially the foot and calf.
3 . Lymphedema tarda : lymphedema that appears above 35
years of age. It is an uncommon form and constitutes less
than 10 % of all lymphedema types.
Causes of Secondary Lymphedemas
1. Post-breast cancer lymphatic axillary clearance (14 % of
cases)
2. Posttraumatic or postsurgical
3. Infectious (e.g., lariasis )
4. Postradiation therapy
5. Due to advanced malignancy
Patients with lymphedema typically present with swelling
in one limb ( lymphedema praecox or tarda ) with maximal
increase in girth of the involved limb. Most patients with
long-standing lymphedema have recurrent so -tissue infection such as cellulitis, erysipelas, tinea pedis, and lymphangitis. Cutaneous changes of long-standing lymphedema include
cutaneous and subcutaneous brosis ( peau d ’ orange skin
changes ), hyperkeratosis, hyperpigmentation, and papillomatous or verrucous changes with increased skin turgor. e
Kaposi - Stemmer sign is a clinical sign indicative of
lymphedema, in which an examiner is unable to pinch a fold
of skin at the base of the second toe on the dorsal aspect of
the foot.
In very rare cases, chronic lymphedema can transform
into cutaneous malignancy such as lymphangiosarcomata,
angiosarcoma ( Stewart – Treves syndrome ), lymphoma, mela-
noma, squamous cell carcinoma, and Kaposi’s sarcoma.
D i ff erential Diagnoses of Lymphedema
1 . Chronic venous insu ciency ( postphlebitic
syndrome / phlebedema ) is a condition characterized by
limb swelling due to chronic venous thrombosis. Patients
usually complain from aching discomfort in the lower
extremities during sitting or standing and chronic
pruritus. Limb examination o en shows dusky-skin
discoloration due to hemosiderin deposition within the
dermis and cutaneous varicosities.
2 . Myxedema is a special form of edema which arises when
abnormal deposits of mucinous substances accumulate
in the skin as a result of thyroid disease (e.g.,
hypothyroidism). It is characterized by roughening of the
skin of the palms, soles, elbows, and knees; brittle, uneven
nails; dull, thinning hair; yellow-orange discoloration of
the skin; and reduced sweat production. However, it may
be di cult to distinguish from lymphedema.
3 . Lipedema is a syndrome characterized by bilateral
symmetrical adipose deposition in the buttocks and lower
extremities, causing subsequent enlargement, which stops
abruptly at the malleoli, sparing the feet ( helpful in
distinguishing this from lymphedema ). It is o en
associated with considerable aching and pain within the
extremity, especially below the knee. Unlike lymphedema,
lipedema is painful on touch, almost exclusively seen in
females, and the skin can easily be bruised due to the
blood vessels’ fragility in the subcutaneous tissue. In
contrast to lipedema, lipohypertrophy is a painless
malfunction of the distribution of fat at the extremities.
e absence of a Kaposi-Stemmer’s sign is an additional
clue. Most o en, lipedema arises within 1–2 years a er
the onset of puberty.
4 . Armchair leg is a descriptive term that results from sitting
in a chair all day and night with one’s legs in a dependent
position. e immobility results in decreased lymphatic
drainage and a functional lymphedema.
5 . Postoperative swelling caused by femoropopliteal bypass
gra ing occurs as a result of disruption, or impaired
lymphatic drainage, secondary to the surgical dissection
in the thigh and popliteal areas. Swelling typically
resolves within 3 months. Non-resolving edema a er 3
months bares the risk of postoperative tibial or popliteal
vein thrombosis.
6 . Podoconiosis ( non - larial elephantiasis ) is a rare
condition typically seen in non- larial regions of tropical
Africa, Central America, and the Indian subcontinent.
e condition is caused by long-term inoculation of
microparticles of silica through the soles of barefoot
walkers.
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Chapter 8 · Dermatology
Signs on US
Lymphedema shows thickened dermis with hypoechoic
texture associated with loss of the normal
cutaneo-myofascial layers distinction. Lymphatic vessels
can be seen on duplex sonography within the thickened
dermis and hypodermis as hypoechoic branches called
Marshall Clefts . Dermal echogenicity is inversely
proportional to its concentration in water; therefore,
dermal edema results therefore in a loss of echogenicity
of the skin in high-resolution cutaneous
ultrasonography.
Signs on CT and MRI
8
1. Typically in lymphedema, there is the absence of edema
within the muscular compartment which helps to
distinguish lymphedema radiographically from other
forms of edema. The subcutaneous tissue shows
thickening and characteristic epifascial plane
honeycombing and thickening of the skin (
The honeycombing appearance of the subcutaneous soft
tissue in lymphedema is thought to be caused by pockets
of fat surrounded by fl uid or fi brous tissue. Phlebedema
in CT will show the same features of lymphedema, but
with thrombosed deep venous system (
2. In lipedema, the subcutaneous fat in CT shows
thickening without the signs of honeycombing.
. Fig. 8.5.1 ).
. Fig. 8.5.2 ).
Signs on Lymphoscintigraphy
Isotopic lymphoscintigraphy is the most commonly used
test and is generally considered to be the gold standard
for the diagnosis of lymphedema. A radiolabeled
macromolecular tracer (e.g., sulfur colloid) is
administered into the subdermal, interdigital region of
the aff ected limb, and the typical abnormalities in
lymphedema include absent or delayed transport of
tracer, absent or delayed visualization of lymph nodes,
crossover fi lling with retrograde backfl ow, and dermal
back fl ow.
3. On MR lymphography, the lymphatic vessels are traced
from the foot upward to the inguinal lymph nodes and
then into the cisterna chyli in the abdomen at the level
of L1 vertebra. The role of MR lymphography is to assess
the level of lymphatic obstruction, seen as abrupt
interruption of the gadolinium in the lymphatic vessels.
T2W, fat-suppressed images often show subcutaneous
edema aff ecting the soft tissues and the underlying
muscles with subfascial fl uid collections (
and
8.5.4 ).
4. Lipedema is seen on MR-W1W images as diff use
subcutaneous fatty tissues that surrounds the lower
limb (
. Fig. 8.5.5 ) .
. Figs. 8.5.3
. Fig. 8.5.1 Axial CT image of a patient with right lower limb lymphedema shows marked subcutaneous edema with epifascial plane
honeycombing
8.5 · Lymphedema
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. Fig. 8.5.2 Axial CT image of a patient with right lower limb phlebedema shows subcutaneous edema with epifascial plane
honeycombing and thrombosis of the deep femoral venous system ( Arrow )
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. Fig. 8.5.3 Multiple coronal, T1W, postcontrast MR-lymphographic images that show lymphedema with areas of interruption of the
gadolinium die in the lymphatic vessels ( arrowheads )
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Chapter 8 · Dermatology
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. Fig. 8.5.4 Coronal ( above ) and axial ( below ) T2W, fat-suppressed images of a patient with lymphedema that shows subcutaneous
lymphatic congestion seen as high T2 signal intensity fl uid in the subcutaneous tissues bilaterally
8.6 · Neuropathic Itch (Pruritus)
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. Fig. 8.5.5 Multiple axial T1W-MR images of a patient with lipedema shows diff use fatty infi ltration of the subcutaneous tissue and
around the muscular structures of the knee
Selected References
Åström KGO, etal. MR imaging of primary, secondary, and
mixed forms of lymphedema. Acta Radiol. 2001;42:409–16.
Child AH, etal. Lipedema: an inherited condition. Am J Med
Genet Part A. 2010;152A:970–6.
Fonder MA, etal. Lipedema, a frequently unrecognized prob-
lem. J Am Acad Dermatol. 2007;57:S1–3.
Hadjis NS, etal. e role of CT in the diagnosis of primary
lymphedema of the lower limb. AJR Am J Roentgenol.
1985;144:361–4.
Kerchner K, etal. Lower extremity lymphedema. Update:
pathophysiology, diagnosis, and treatment guidelines. Am
Acad Dermatol. 2008;59:324–31.
Lu Q, etal. Chronic lower extremity lymphedema: a compar-
ative study of high-resolution interstitial MR lymphangiography and heavily T2-weighted MRI. Eur J Radiol.
2010;73:365–73.
Naouri M, etal. High-resolution cutaneous ultrasonography
to di erentiate lipoedema from lymphoedema. Br J
Dermatol. 2010;163:296–301.
Rockson SG.Lymphedema. Am J Med. 2001;110:288–95.
8.6 Neuropathic Itch (Pruritus)
Pruritus ( itching ) represents a distinct sensation arising from
the super cial layers of the skin, the mucous membranes
( including the upper respiratory tract ), and the conjunctivae.
Itch can be classi ed into four main types:
1 . Pruritoceptive itch arises in the skin because of dryness,
in ammation, or other skin damage.
2 . Psychogenic itch arises in patients with psychiatric
disorders, such as “delusional parasitosis.”
3 . Neurogenic itch arises in the CNS without evidence of
neural pathology; an example is the itch of cholestasis
caused by the action of neuropeptides on opioid
receptors.
4 . Neuropathic itch is a pathological condition characterized
by out of proportion itch that is completely independent
of any pruritogenic stimuli and arises from a lesion in
any point along the sensory pathway. is type of itch
does not o en respond to antihistamines, topical steroids,
or other medications that are e ective in treating of
conventional itch.
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Chapter 8 · Dermatology
e sensation of itching is linked with the motor response
of scratching via a spinal re ex and can be inhibited by cortical
centers. Scratching relieves itching for several minutes. Scratching is thought to stimulate large, fast conducting A- bers adjacent to those conducting pruritus. e A- bers synapse with
the inhibitory interneurons and subsequently inhibit the
C- bers, thus reducing the pruritic sensation, according to the
“gate control theory” of Melzack and Wall (1965).
e role of radiology in pruritus is to detect its nondermatological di erential diagnoses, especially those rare
cases that arise from central nervous system causes, since
both the skin and the neural tissues arise embryologically
from the ectoderm.
Neural Control Pruritus
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1 . Higher centers : cortical centers that modulate itch
sensation include the “primary somatosensory cortex”
and the “insula.”
2 . alamus : the “posterolateral ventral thalamic nucleus”
acts as a relay station delivering sensation of pruritus
coming from the spinal cord via the “anterolateral
spinothalamic tract” to the “primary somatosensory
cortex” and the “insula.”
3 . Spinal cord : itch impulses are conducted to the ipsilateral
dorsal root ganglia and synapse there with secondary
neurons. A erents from these neurons immediately cross
over to the opposite anterolateral spinothalamic tract. In
the spinal cord, itch and pain processing can be
sensitized such that touch stimuli evoke itch ( alloknesis )
or pain ( touch allodynia ).
4 . Pruriceptive receptors : itch is mediated by small
unmyelinated (C- ber) axons that also transmit pain
sensation. Pruriceptive receptors are activated by one of
the itch mediators which are:
(a) Histamine : it causes severe itching if applied to the
super cially damaged skin or injected intradermally.
If injected deeper, histamine produces pain. e
majority of histamine released in the skin originates
from the dermal mast cells, usually in response to an
allergen.
(b) Serotonin : it acts directly on peripheral serotonergic
receptors inducing itch. Serotonin acts on the
C- bers via 5-HT3 receptors, which appear to be
involved in the pathophysiology of both pruritus and
pain.
(c) Opioids : endogenous opioids exert a regulatory
action on pain and itching through the CNS; opioids
cause pruritus by acting directly on the μ -opioid
receptors and by releasing histamine from mast cells.
D i ff erential Diagnoses of Neuropathic Itch
1 . Psychogenic pruritus : itching described by the patient as
insects crawling over the skin (tactile hallucinations/
delusional parasitosis).
2 . Malignancy pruritus : it is described in multiple myeloma,
leukemia, lymphoma, Hodgkin’s disease, rectal or
sigmoid cancer, and carcinoma of the cervix.
3 . Aquagenic pruritus : it is a skin condition
characterized by intense itching, sometimes
accompanied by a burning or stinging sensation after
contact with water, regardless of temperature, without
any cutaneous alterations and skin or systemic
disease. It may be an isolated symptom or accompany
different proliferative disorders, like polycythemia
vera. The discomfort appears 1–5min after exposure
to water and lasts for 10–120min. The pathology is
presumed to be caused by increased degranulation of
the mast cells after the contact with water and the
release of acetylcholine.
4 . Notalgia paresthetica is an area of pruritus of the
mid-back due to a form of peripheral
neuropathy involving the T2–T6 thoracic nerves
due to disk prolapse. It is characterized by focal,
intense itching on a patch of the skin of the medial
scapular border.
5 . Infectious causes : herpes zoster ( shingles ) is the
commonest cause of neuropathic itch. Postherpetic
neuralgia is a chronic neuropathic pain persisting more
than 3 months a er the shingles rash resolves.
6 . Glossopharyngeal pruritus is an itch that is felt in the
throat or behind the angle of the jaw. Some patients with
itch from CN 9 or CN 10 lesions report a tickle in their
throat that causes chronic cough.
7 . Trigeminal trophic syndrome is a rare disorder that arises
due to destruction to the trigeminal ( Gasserian )
ganglion, resulting in ipsilateral nasal ala itch and trophic
skin ulceration.
8 . Central pruritus arises due to brain and/or spinal cord
insult due to multiple sclerosis, neuro-Sjögren’s
syndrome, syrinx, Wallenberg syndrome, strokes (21 %),
Creutzfeldt–Jakob disease, and intramedullary
cavernoma.
References
Carstens E.Scratching the brain to understand neuropathic
itch. J Pain. 2008;9(11):973–4.
Cohen OS, etal. Pruritus in familial Creutzfeldt–Jakob dis-
ease: a common symptom associated with central nervous
system pathology. J Neurol. 2011;258:89–95.
8.6 · Neuropathic Itch (Pruritus)
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Curtis AR, etal. Holistic approach to treatment of intractable
central neuropathic itch. J Am Acad Dermatol.
2011;64:955–9.
Ikoma A, etal. Anatomy and neurophysiology of pruritus.
Semin Cutan Med Surg. 2011;30:64–70.
Krajnik M, etal. Understanding pruritus in systemic disease.
J Pain Symptom Manage. 2001;21:151–68.
Lanotte M, etal. Central neuropathic itch as the presenting
symptom of an intramedullary cavernous hemangioma:
case report and review of literature. Clin Neurol
Neurosurg. 2013;115:454–6.
Magrinelli F, et al. Neuropathic pain: diagnosis and treat-
ment. Pract Neurol 2013;13(5):292–307.
Metz M, et al. Chronic pruritus – pathogenesis, clinical
aspects and treatment. J Eur Acad Dermatol Venereol.
2010;24:1249–60.
Oaklander AL. Neuropathic itch. Semin Cutan Med Surg.
2011;30:87–92.
Sandroni P. Central neuropathic itch: a new treatment
option? Neurology. 2002;59:778.
Schmelz M. Itch and pain. Neurosci Biobehav Rev.
2010;34:171–6.
Wiesner T, etal. Itch, skin lesions—and a sti neck. Lancet.
2007;370:290.
Wood GJ, et al. An insatiable itch. J Pain. 2009;10(8):
792–7.
H e m a t o l o g y
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9.1 Hemosiderosis andHemochromatosis – 348
Di erential Diagnoses andRelated Diseases – 349
9.2 β-Thalassemia Major (Cooley’s Anemia) – 350
9.3 Sickle Cell Disease – 353
The Lungs inSCD – 354
The Skeletal System inSCD – 354
The Brain inSCD – 354
The Spleen inSCD – 354
9.4 Pernicious Anemia – 357
9.5 Hemophilia – 358
Di erential Diagnoses andRelated Diseases – 359
347
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9.6 Lymphomas – 362
Cotswold Staging ofLymphoma – 363
Criteria forTherapy Response Assessment – 363
Di erential Diagnoses andRelated Diseases – 363
9.7 Leukemia – 368
Acute Lymphoblastic Leukemia – 368
Acute Myeloblastic Leukemia – 368
Chronic Lymphocytic Leukemia – 369
Chronic Myelogenous Leukemia – 369
9.8 Multiple Myeloma (Kahler’s Disease) – 374
9.9 Amyloidosis – 378
Classi cation ofAmyloidosis (Clinical-Based Classi cation) – 378
9.10 Evans’ Syndrome – 382
9.11 Other Lymphatic Disorders – 383
Castleman’s Disease (Angiofollicular Lymph Node Hyperplasia) – 383
Kikuchi–Fujimoto Disease (Histiocytic Necrotizing Lymphadenitis) – 384
Kimura’s Disease – 384
9.12 Mastocytosis – 385
9.13 Myelo brosis andMyeloid Metaplasia – 387
© Springer International Publishing Switzerland 2017
J.A. Al-Tubaikh, Internal Medicine, DOI10.1007/978-3-319-39747-4_9
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Chapter 9 · Hematology
9.1 Hemosiderosis andHemochromatosis
Hemosiderosis , or iron overload, is a pathological condition
characterized by deposition of excess iron within the body
tissues that normally do not contain iron. Hemosiderosis is
usually secondary to a primary cause such as multiple blood
transfusion, chronic hemodialysis, or hemolytic anemia (e.g.,
thalassemia).
When iron is released into the cytoplasm, it enters a cellular compartment called “labile iron pool” (LIP). Both ferrous (Fe 2+ ) and ferric (Fe 3+ ) iron forms are poorly bound
with proteins and are highly toxic to the cells within this
compartment. e unneeded iron from LIP is stored in the
form of ferritin, which is organic and nontoxic. When the LIP
iron content exceeds the ferritin capacity, hemosiderin is
generated from ferritin denaturation. Iron in the form of
hemosiderin is thought to be more toxic to the body tissues.
Hemosiderin initially accumulates in the reticuloendothelial
system (spleen, bone marrow, and Kup er cells in the liver).
9
When the reticuloendothelial system is saturated, deposition
occurs in normal body tissues such as the hepatocytes, heart
muscles, and the endocrine system. Chelation therapy (e.g.,
desferrioxamine) removes mainly the extracellular iron and
. Fig. 9.1.1 Short-axis cardiac MRI illustration demonstrates
a black ring within the myocardium, a sign of cardiac siderosis
( arrowhead )
only a fraction of the intracellular LIP iron.
Hemosideroses have di erent body manifestations
according to the area of deposition:
5 Cardiac hemosiderosis : myocardial iron deposition results
in dilated cardiomyopathy that will lead to heart failure.
Signs on Chest Radiograph
The heart appears larger than normal in cases of cardiac
damage and development of dilated cardiomyopathy.
Signs on CT and MRI
5 On CT, the liver appears hyperdense compared to
the spleen.
5 On MRI, the liver appears extremely hypointense,
with an almost black signal on all pulse sequences,
depending on the severity of the iron overload.
5 Anterior pituitary gland hemosiderosis : loss of the
endocrine function of the anterior pituitary results
in hypogonadism and loss of libido.
Signs on MRI
MRI can detect early myocardial siderosis via obtaining
T2* images, which show a dark, hypointense rim located
within the myocardium in short-axis sequences,
representing myocardial siderosis (. Fig. 9.1.1 ).
5 Hepatic hemosiderosis : iron deposition in
hepatocytes results in liver cirrhosis.
Signs on MRI
The anterior pituitary shows a hypointense signal
intensity area on both T1 and T2 images.
5 Pancreatic hemosiderosis : deposition of iron in the
pancreases results in impairment of both exocrine
and endocrine functions. Diabetes mellitus may
result due to pancreatic siderosis.
9.1 · Hemosiderosis andHemochromatosis
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Signs on US
5 The normal pancreas has almost the same
echogenicity as the liver on ultrasound. In
siderosis, the pancreas may appear hyperechoic
compared to the liver, due to iron overload. Other
causes of hyperechoic pancreas include fatty
infiltration and pancreatic calcification.
Signs on MRI
Pancreatic hemosiderosis are detected as hypointense
signal intensity areas are seen within the pancreas on
both T1W and T2W images.
Hemochromatosis is a disease characterized by deposition
of excess iron in the body as a result of genetic defect (primary hemosiderosis).
In hemochromatosis, iron deposition initially occurs in
the hepatocytes and spares Kup er cells (the reverse situation
to hemosiderosis). e age of presentation is usually between
50 and 60 years of age. Menstruation blood loss in women
has a protective e ect against hemochromatosis due to iron
loss.
Hemochromatosis is asymptomatic in early stages. As the
iron deposition progresses, liver failure, skin hyperpigmentation, arthropathy (especially in the metacarpophalangeal
joints), and cardiac failure may occur. Deposition of hemosiderin in the subcutaneous tissues results in increased skin
tanning and darkening.
Bronze diabetes is a term used to describe maturity-onset
diabetes seen in hemochromatosis. e term “bronze” is used
because the diabetes is associated with skin tanning that
mimics bronze coloring.
Diagnosis is con rmed by measuring serum ferritin level,
transferrin saturation testing, liver biopsy, genetic testing,
and MRI.
D i erential Diagnoses andRelated Diseases
5 Bantu siderosis a type of hemosiderosis only found in
Africa. It is associated with liver cirrhosis, diabetes, and
heart disease. e disease is linked with higher rates of
tuberculosis infection.
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5 Juvenile hemochromatosis is a form of hemochromatosis
present in the second decade of life. Patients o en
present with abdominal pain, cardiac arrhythmias,
impaired glucose tolerance, and hypogonadotropic
hypogonadism.
5 Ferroportin disease is a genetic disease characterized by
mutation in the gene responsible for the production of
ferroportin, a protein that exports iron from body
cells. Ferroportin is expressed mainly in Kup er cells
and splenic macrophages. Patients present with
isolated hyperferritinemia and normal or slightly
elevated transferrin saturation. In contrast to
hemochromatosis, iron is mainly deposited within
Kup er cells.
5 Pulmonary hemosiderosis is a rare condition that arises
due to repeated episodes of bleeding within the lung
alveoli. Iron overload within the lungs results in
pulmonary brosis, anemia, and (rarely) death due to
pulmonary hemorrhage. e disease has an incidence of
less than 1:1,000,000 live births and occurs usually in
children <7years old (it is extremely rare in adults).
Symptoms include coughing blood (hemoptysis) and
iron-de ciency anemia.
5 Super cial brain siderosis is a condition characterized by
deposition of hemosiderin within brain tissues, o en
secondary to subdural hemorrhage and bleeding into the
brain cisterns. When siderosis a ects the
vestibulocochlear nerve, tinnitus may result.
Signs on MRI
5 The liver appears extremely hypointense on all
pulse sequences, depending on the iron overload
severity.
5 The muscles and kidneys may appear
hyperintense, due to iron deposition.
5 The spleen is characteristically spared and
unaffected in hemochromatosis. In contrast, the
spleen is almost always affected in hemosiderosis.
5 I n superficial brain siderosis , a characteristic band
of low T1 and T2 signal intensity is seen around the
brain tissue, especially the pons, due to its location
within the pontine cistern (. Fig. 9.1.2 ) .
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