Chapter 11: Tumor

Question 1

Tumors of blood vessels and lymphatics range from ( Table 11-5 ).

Answer 1

benign hemangiomas to lesions that are
locally aggressive but infrequently metastasize, to relatively rare, highly malignant
angiosarcomas

• Primary tumors of large vessels (aorta, pulmonary artery, and vena cava) are extremely rare and are mostly connective tissue sarcomas.
• Congenital or developmental malformations and reactive vascular proliferations (e.g., bacillary angiomatosis) can also present as tumor-like lesions.

Question 2

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Answer 2

• Hemangioma
• Lymphangioma
• Glomus tumor
• Vascular ectasias
• Reactive vascular proliferations

Question 3

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

INTERMEDIATE-GRADE NEOPLASMS

Answer 3

• Kaposi sarcoma
• Hemangioendothelioma

Question 4

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

MALIGNANT NEOPLASMS

Answer 4

Angiosarcoma
Hemangiopericytoma

Question 5

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Hemangioma

Answer 5

• Capillary hemangioma
• Cavernous hemangioma
• Pyogenic granuloma

Question 6

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Lymphangioma

Answer 6

• Simple (capillary) lymphangioma
• Cavernous lymphangioma (cystic hygroma)

Question 7

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Glomus tumor

Question 8

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Vascular ectasias

Answer 8

• Nevus flammeus
• Spider telangiectasia (arterial spider)
• Hereditary hemorrhagic telangiectasis (Osler-Weber-Rendu disease)

Question 9

TABLE 11-5 – Classification of Vascular Tumors and Tumor-like Conditions

BENIGN NEOPLASMS, DEVELOPMENTAL AND ACQUIRED CONDITIONS

Reactive vascular proliferations

Answer 9

Bacillary angiomatosis

Question 10

Vascular neoplasms can be endothelium-derived (e.g., hemangioma, lymphangioma, angiosarcoma) or arise from cells that support and/or surround blood vessels (e.g., glomus tumor, hemangiopericytoma).

Although a benign, welldifferentiated hemangioma can usually be readily discriminated from an anaplastic high-grade angiosarcoma, the distinction between
benign and malignant can occasionally be difficult.

Two general rules of thumb are as follows:

Answer 10

• Benign tumors usually produce obvious vascular channels filled with blood cells or lymph, lined by a layer of normal-appearing endothelial cells.
• Malignant tumors are more cellular, show cytologic atypia, and are proliferative,
  including mitotic figures; they usually do not form well-organized vessels. The endothelial derivation of neoplasms that do not form distinct vascular lumens can usually be confirmed by immunohistochemical demonstration of endothelial cell–specific
  markers such as CD31 or von Willebrand’s factor.

Question 11

What are hemangiomas?

Answer 11

• very common tumors characterized by increased numbers of normal or abnormal vessels filled with blood ( Fig. 11-30 );
• they may be difficult to distinguish from vascular malformations.
• 7% of all benign tumors of infancy and childhood; most are present from birth and expand along with the growth of the child.

Nevertheless, many of the capillary lesions eventually regress spontaneously. Although some
hemangiomas can involve large portions of the body (angiomatosis), most are localized.

Question 12

What is the majority of hemangiomas?

Answer 12

The
majority are superficial lesions, often of the head or neck, but they can occur internally, with
nearly one third being found in the liver

. Malignant transformation occurs rarely, if ever.

Question 13

What are the
several histologic and clinical variants of Hemangioma?

Answer 13

FIGURE 11-30 Hemangiomas.

• A, Hemangioma of the tongue.
• B and C, Histologic
• appearance of (B) juvenile capillary hemangioma and
• (C) cavernous hemangioma.
• D, Pyogenic granuloma of the lip.

Question 14

What is Capillary Hemangioma?

Answer 14

• most common variant,
• occur in the skin, subcutaneous tissues, and mucous membranes of the oral cavities and lips, as well as in the liver, spleen, and kidneys.

Question 15

What is the most common capillary hemangioma?

Answer 15

The “strawberry type” or juvenile hemangioma of the skin of newborns is extremely common (1
in 200 births) and may be multiple.

It grows rapidly in the first few months but then fades at 1 to 3 years of age and completely regresses by age 7 in 75% to 90% of cases.

Question 16

What is the morphology of Capillary hemangiomas?

Answer 16

• bright red to blue and vary from a few millimeters to several centimeters in diameter;
• hemangiomas can be level with the surface of the skin or slightly elevated, and have an intact overlying epithelium ( Fig. 11-30A ).

Question 17

What is the appearance of capillary hemangioma histologically?

Answer 17

• unencapsulated aggregates of closely packed, thin-walled capillaries,
• usually bloodfilled and lined by flattened endothelium;
• vessels are separated by scant connective tissue stroma ( Fig. 11-30B ).
• The lumens may be partially or completely thrombosed and organized.
• Vessel rupture accounts for hemosiderin pigment in these lesions as well as focal scarring.

Question 18

What is Cavernous Hemangioma?

Answer 18

These exhibit large, dilated vascular channels; compared with capillary hemangiomas,
cavernous hemangiomas are less well circumscribed and more frequently involve deep
structures

Since they may be locally destructive and show no spontaneous tendency to regress, some may require surgery

Question 19

In most cases, the tumors are of little clinical significance; however, they can be a cosmetic disturbance and are vulnerable to traumatic ulceration and bleeding.

Moreover, visceral hemangiomas detected by imaging studies may have to be distinguished from more ominous (e.g., malignant) lesions.

Question 20

Why are Brain hemangiomas are most
problematic?

Answer 20

because they can cause pressure symptoms or rupture.

Question 21

Cavernous hemangiomas
are a component of __________( Chapter 28 ), occurring within the cerebellum,
brain stem, or retina, along with similar angiomatous lesions or cystic neoplasms in the
pancreas and liver

Answer 21

von Hippel-Lindau disease

von Hippel-Lindau disease is also associated with renal neoplasms.

Question 22

What is the morphology of Cavernous hemangiomas?

Answer 22

• red-blue,
• soft,
• spongy masses 1 to 2 cm in diameter;
• rare giant forms can affect large subcutaneous areas of the face, extremities, or other body regions.

Question 23

What is the Histological morphology of Cavernous hemangiomas

Answer 23

• sharply defined but not encapsulated, and
• composed of large, cavernous blood-filled vascular spaces, separated by a modest connective tissue stroma ( Fig. 11-30C ).
• Intravascular thrombosis with associated dystrophic calcification is common.

Question 24

What is Pyogenic Granuloma?

Answer 24

• form of capillary hemangioma
• rapidly growing pedunculated red nodule on the skin, or gingival or oral mucosa;
• it bleeds easily and is often ulcerated ( Fig. 11-30D ).

Question 25

1/3 of the Pyogenic Granuloma deveolp after what?

Answer 25

trauma

reaching a size of 1 to 2 cm within a few weeks

The proliferating capillaries are often accompanied by extensive edema and an acute and chronic
inflammatory infiltrate,strikingly similar to exuberantgranulation tissue.

Question 26

1% of the patients of Pyogenic granuloma occurs where?

Answer 26

pregnant women.

Pregnancy tumor
(granuloma gravidarum) is a pyogenic granuloma that occurs infrequently (1% of patients) in the gingiva of pregnant women.

These lesions can spontaneously regress (e.g., after
pregnancy) or undergo fibrosis; in some cases surgical excision is required. Recurrence is rare.

Question 27

What are lymphagiomas?

Answer 27

Lymphangiomas are the benign lymphatic analogues of blood vessel hemangiomas

Question 28

What is Simple (Capillary) Lymphangioma?

Answer 28

.
These are composed of small lymphatic channels predominantly occurring in the head, neck,
and axillary subcutaneous tissues.

They are slightly elevated or sometimes pedunculated
lesions up to 1 to 2 cm in diameter.

Question 29

How can you distinguised lymphaiomas from capillary channels?

Answer 29

Histologically, lymphangiomas exhibit networks of
endothelium-lined spaces that can be distinguished from capillary channels only by the
absence of erythrocytes.

Question 30

What is Cavernous Lymphangioma (Cystic Hygroma)?

Answer 30

These lesions are typically found in the neck or axilla of children, and rarely occur in the
retroperitoneum;

Question 31

To what symdrome is cavernous lymphangiomas of the neck is more common?

Answer 31

cavernous lymphangiomas of the neck are common in Turner syndrome

Question 32

What is the morphology of Cavernous lymphaiomas?

Answer 32

Cavernous lymphangiomas can occasionally be enormous (up to 15 cm in diameter) and may fill the axilla or produce gross deformities about the neck.

Tumors are
composed of massively dilated lymphatic spaces lined by endothelial cells and separated by
intervening connective tissue stroma containing lymphoid aggregates.

The tumor margins are
not discrete and the lesions are not encapsulated, making definitive resection difficult.

Question 33

What is Glomus tumor?

Answer 33

Glomus tumors are benign, exquisitely painful tumors arising from modified smooth muscle cells
of the glomus body, a specialized arteriovenous structure involved in thermoregulation.
Although they can resemble cavernous hemangiomas, glomus tumors constitute a distinct entity
by virtue of their constituent cells. They are most commonly found in the distal portion of the
digits, especially under the fingernails. Excision is curative.

Question 34

Althoug Glomus Tumor can resemble cavernous hemangiomas, glomus tumors constitute a

Answer 34

distinct entity
by virtue of their constituent cells.

They are most commonly found in the distal portion of the digits, especially under the fingernails.

Excision is curative

Question 35

What is the morphology of Glomus tumor?

Answer 35

• round,
• slightly elevated,
• red-blue,
• firm nodules (usually <1 cm in diameter) that initially resemble a minute focus of hemorrhage.

Question 36

What is the morphology of Glomus tumor Histologically,?

Answer 36

aggregates, nests, and masses of specialized glomus cells intimately associated with branching vascular channels, all within a connective tissue stroma.
Individual tumor cells are small, uniform, and round or cuboidal, with scant cytoplasm and
ultrastructural features akin to smooth muscle cells

Question 37

What are Vascular Ectasias?

Answer 37

Vascular ectasias are common lesions characterized by local dilation of preexisting vessels; they are not true neoplasms.

Telangiectasia is a term used for a congenital anomaly or
acquired exaggeration of preformed vessels—usually in the skin or mucous membranes
—composed of capillaries, venules, and arterioles that creates a discrete red lesion

Question 38

What is Telangiectasia?

Answer 38

Telangiectasia is a term used for a congenital anomaly or
acquired exaggeration of preformed vessels—usually in theskin or mucous membranes
—composed of capillaries, venules, and arterioles that creates a discrete red lesion

Question 39

What is Nevus Flammeus?

Answer 39

This lesion is the ordinary “birthmark” and is the most common form of ectasia;

it is

• *characteristically a flat lesion on the head or neck,** ranging in color from **light pink to deep
  purple. **

Histologically, there is only vascular dilation; most ultimately regress.

Question 40

What is port wine stain?

Answer 40

special form of nevus flammeus; these lesions tend to grow with a child, thicken the skin surface, and demonstrate no tendency to fade.

Question 41

What is Sturge-Weber syndrome (also
called encephalotrigeminal angiomatosis)?

Answer 41

Such nevus flammeus in a
trigeminal nerve distributionare occasionally associated with the Sturge-Weber syndrome (also
called encephalotrigeminal angiomatosis).

Sturge-Weber syndrome is a rare congenital
disorder associated with venous angiomatous masses in the cortical leptomeninges and
ipsilateral facial port wine nevi;mental retardation, seizures, hemiplegia, and skull
radioopacities also occur

Thus, a large facial vascular malformation in a child with mental
deficiency may indicate the presence of more extensive vascular malformations.

Question 42

What is Spider Talengiectasia?

Answer 42

This non-neoplastic vascular lesion grossly resembles a spider; there is a radial, often pulsatile
array of dilated subcutaneous arteries or arterioles (resembling legs) about a central core (resembling a body) that blanches when pressure is applied to its center.

It is commonly seen
on the face, neck,orupper chest and is most frequently associated with hyper-estrogenic
states such as pregnancy or patients with cirrhosis;how elevated estrogen levels contribute to
“spider” formation is not known.

Question 43

Spider Talengiectasia is commonly seen where>

Answer 43

It is commonly seen
on the face, neck, or upper chest and is most frequently associated with hyper-estrogenic
states such as pregnancy or patients with cirrhosis; how elevated estrogen levels contribute to
“spider” formation is not known.

Question 44

What is Hereditary Hemorrhagic Telangiectasia (OslerWeber-Rendu Disease)?

Answer 44

• autosomal dominant disorder the telangiectasias are malformations composed of dilated capillaries and veins.
• Present from birth, they are widely distributed over the skin and oral mucous membranes, as well as in the respiratory, gastrointestinal, and urinary tracts.
• Occasionally, these lesions rupture, causing serious epistaxis (nosebleeds), GI bleeding, or hematuria.

Question 45

What is Bacillary angiomatosis?

Answer 45

• vascular proliferation resulting from an opportunistic infection in immunocompromised individuals;
• lesions can involve skin, bone, brain, and other organs.
• First described in patients with acquired immunodeficiency syndrome (AIDS)

Question 46

Bacillary angiomatosis is caused by what infection?

.

Answer 46

infection with gram-negative bacilli of the Bartonella family.

Question 47

What are the two species which are implicated with Bacillary angiomatosis
:

Answer 47

• Bartonella henselae, the organism responsible for cat-scratch disease (the domestic cat is the principal reservoir), and
• B. quintana, the cause of “trench fever” in World War I (the organism is transmitted by human body lice)

Question 48

What is the morphology of Bacillary Angiomatosis?

Answer 48

• Skin lesions are red papules and nodules, or rounded subcutaneous masses;
• histologically, there is capillary proliferation with prominent epithelioid endothelial cells exhibiting nuclear atypia and mitoses ( Fig. 11-31 ).
• Lesions contain neutrophils, nuclear dust, and the causal bacteria.

Though difficult to cultivate in the laboratory, the bacteria can be unequivocally demonstrated
using molecular methodssuch aspolymerase chain reaction with species-specific primers.

The vascular proliferation results from induction of host HIF-1α by the bacteria; HIF-1α in turn
drives VEGF production. [86]

Question 49

What is the treatment for Bacillary Angiomatosis?

Answer 49

The infections (and lesions) are cleared by macrolide antibiotics (including erythromycin

Question 50

Answer 50

FIGURE 11-31 Bacillary angiomatosis.

A, Photograph of a cutaneous lesion

. B, Histologic appearance with acute neutrophilic inflammation and vascular (capillary) proliferation.
(Inset) Demonstration by modified silver (Warthin-Starry) stain of clusters of tangled bacilli
(black).

Question 51

INTERMEDIATE-GRADE (BORDERLINE) TUMORS

Kaposi Sarcoma

Though rare in other populations, Kaposi sarcoma (KS) is common in patients with____________ ;

Answer 51

AIDS

Question 52

Four forms of the
disease are recognized (based primarily on population demographics and risks), although all
share the same underlying viral pathogenesis [87] (see below):

Answer 52

• Chronic KS (also called classic or European KS)
• Lymphadenopathic KS (also called African or endemic KS)
• Transplant-associated KS
• AIDS-associated (epidemic) KS

Question 53

The presence of this is used as a criterion for diagnosing AIDS ( Chapter 6 ).

Answer 53

Kaposi Sarcoma

Question 54

What is Chronic KS?

Answer 54

Chronic KS (also called **classic or European KS)** was first described by Kaposi in 1872;
it **characteristically occurs in older men** of **Eastern European (especially Ashkenazi
Jews) or Mediterranean descent and is uncommon in the United States**.

While chronic
KS can be associated with an underlying second malignancy or altered immunity, it is
not associated with human immunodeficiency virus (HIV).

Question 55

What is the presentaiton of Chronic KS?

Answer 55

Chronic KS presents with
multiple red to purple skin plaques or nodules, usually in the distal lower extremities;
these slowly increase in size and number and spread more proximally.

Although locally
persistent, the tumors are typically asymptomatic and remain localized to the skin and
subcutaneous tissu

Question 56

What is Lymphadenopathic KS (also called African or endemic KS)?

Answer 56

• also called African or endemic KS)
• has the same general geographic distribution as Burkitt lymphoma and is particularly prevalent among South African Bantu children
• it is also not associated with HIV
  *

Question 57

What is the presentation of Lymphadenopathic KS (also called African or endemic KS)?

Answer 57

• .Skin lesions are sparse, and
• patients present instead with lymphadenopathy due to KS involvement;
• the tumor occasionally involves the viscera and is extremely aggressive.

In combination with AIDSassociated KS (see below), KS is now the most common tumor in central Africa (50% of

• all tumors in men in some countries)

Question 58

What is Transplant-associated KS?

Answer 58

occurs in the setting of solid-organ transplantation with its attendant long-term immunosuppression.

It tends to be aggressive (even fatal) with
nodal, mucosal, and visceral involvement; cutaneous lesions may be absent.

Lesions
occasionally regress when immunosuppressive therapy is attenuated, but at the risk of
organ rejection.

Question 59

What is AIDS-associated (epidemic) KS?

Answer 59

was originally found in a third of AIDS patients,
particularly male homosexuals ( Chapter 6 ).

However, with current regimens of
antiretroviral therapy, KS incidence is now less than 1% (although it is still the most prevalent malignancy in AIDS patients in the United States).

AIDS-associated KS can
involve lymph nodes or viscera and disseminates widely early in the course of the
disease.

Most patients eventually die of opportunistic infections rather than from KS.

Question 60

What virus was identified in a cutaneous KS lesion in an AIDS patient ( Chapter 6 ).?

Answer 60

human herpesvirus-8 (HHV-8) or KSassociated
herpesvirus (KSHV)

Indeed, regardless of the clinical subtype (described above), 95% of KS lesions have subsequently been shown to be KSHV-infected. [88]

Like Epstein-Barr virus, KSHV is a
member of the γ-herpesvirus subfamily;it istransmitted sexually and by poorly understood
nonsexual routes—perhaps including saliva.

Question 61

What is the pathogenesis of Kaposi Sarcoma?

Answer 61

KSHV is accepted as a necessary requirement for KS development, but tumor progression also
requires a cofactor; HIV clearly can provide this, but the identity of the cofactor in non-HIVassociated
KS is controversial.

KSHV induces a lytic as well as a latent infection in endothelial cells, both of which are probably important in KS pathogenesis.

Cytokines derived from HIVinfected
T cells, or inflammatory cells recruited in response to the lytic infection, create a local proliferative milieu; a virally encoded G protein also induces local VEGF production.

In latently
infected cells, KSHV proteins disrupt normal cellular proliferation controls and prevent apoptosis
by viral production of p53 inhibitors and a viral homologue of cyclin D.

Thus, latently infected
cells have a growth advantage; the local environment also favors cellular proliferation.

The increasing recognition of the various viral gene products has nevertheless opened a number of
new avenues for therapeutic interventions against affected intracellular kinase pathways and
downstream targets.

In its early stages, only a few cells are infected; with time virtually all spindle cells of late-stage lesions carry KSHV; these spindle cells express both endothelial cell
and smooth muscle cell markers.

Question 62

Morphology of Kaposi Sarcoma.

In the indolent, classic disease of older men (and sometimes in other variants),
three stages are recognized:

Answer 62

• patch,
• plaque, and
• nodule.

Question 63

Describe the patch morphology in Kaposi Sarcoma?

Answer 63

Patches are red to purple macules typically confined to the distal lower extremities (
Fig. 11-32A ).

Histology shows only dilated irregular endothelial cell–lined vascular
spaces with interspersed lymphocytes, plasma cells, and macrophages (sometimes
containing hemosiderin).

The lesions can be difficult to distinguish from granulation
tissue.

Question 64

Describe the raised plaques morphology in Kaposi Sarcoma?

Answer 64

With time, lesions spread proximally and become larger, violaceous, raised plaques
(see Fig. 11-32A ) composed of dermal accumulations of dilated, jagged vascular
channels lined and surrounded by plump spindle cells.

Scattered between the
vascular channels are extravasated red cells, hemosiderin-laden macrophages, and
other mononuclear inflammatory cells.

Question 65

Describe the raised nodular morphology in Kaposi Sarcoma?

Answer 65

Eventually, lesions become nodular and more distinctly neoplastic.

These lesions are
composed of sheets of plump, proliferating spindle cells, mostly in the dermis or
subcutaneous tissues( Fig. 11-32B ),encompassing small vessels and slitlike spaces
containing red cells.

More marked hemorrhage, hemosiderin pigment, and
mononuclear inflammation is present; mitotic figures are common, as are round, pink,
cytoplasmic globules of uncertain nature.

The nodular stage often heralds nodal and
visceral involvement, particularly in the African and AIDS-associated variants.

Question 66

Answer 66

FIGURE 11-32 Kaposi sarcoma. A, Gross photograph, illustrating coalescent red-purple
macules and plaques of the skin. B, Histologic appearance of nodular form, demonstrating
sheets of plump, proliferating spindle cells.

Question 67

What is the clinical feature of KS?

Answer 67

The course of KS varies widely and is significantly affected by the clinical setting.

Most primary KSHV infections are asymptomatic.

Classic KS is—at least initially—largely restricted to the
surface of the body, and surgical resection is usually adequate for an excellent prognosis.

Question 68

What is the treatment for Kaposi Sarcoma?

Answer 68

• Radiation can be used for multiple lesions in a restricted area, and chemotherapy yields satisfactory results for more disseminated disease.
• Lymphadenopathic KS can also be
• *treated** with chemotherapy or radiation therapy with good results.
• In i mmunosuppression-associated KS, withdrawal of immunosuppression (perhaps with adjunct chemotherapy or radiation therapy) is often effective.
• For AIDS-associated KS, antiretroviral therapy for HIV is usually helpful, with or without therapy targeted to the KS lesions.
• IFN-α and angiogenesis inhibitors are variably effective, while newer strategies aimed at specific intracellular kinase pathways or the downstream mammalian target of rapamycin are showing promise

Question 69

What is Hemangioendothelioma?

Answer 69

Hemangioendothelioma denotes a wide spectrum of vascular neoplasms with clinical behaviors
intermediate between benign,well-differentiated hemangiomas and highly malignant
angiosarcomas, described below.

Epithelioid hemangioendothelioma is an example; it is a vascular tumor of adults occurring
around medium-sized and large veins

. The tumor cells are plump and often cuboidal
(resembling epithelial cells); well-defined vascular channels are inconspicuous.

Clinical
behavior is variable; most are cured by excision, but up to 40% recur, 20% to 30% eventually
metastasize, and perhaps 15% of patients die of the tumors.

Question 70

What are Angiosarcomas?

Answer 70

Angiosarcomas are malignant endothelial neoplasms ( Fig. 11-33 ) with histology varying from
well-differentiated tumors that resemble hemangiomas (hemangiosarcoma) to anaplastic lesions
difficult to distinguish from carcinomas or melanomas.

Answer 71

• FIGURE 11-33 Angiosarcoma.
• A, Gross photograph of angiosarcoma of the heart (right ventricle).
• B, Photomicrograph of moderately well-differentiated angiosarcoma with densen clumps of irregular, moderate anaplastic cells and distinct vascular lumens.
• C, Immunohistochemical staining for the endothelial cell marker CD31, demonstrating the endothelial nature of the tumor cells.

Question 72

What is the predilection of Angiosarcoma with regarrds to age and gender?

Answer 72

Older adults are more commonly
affected,withequal gender predilections;they occur atany site but most often involve skin, soft
tissue, breast, and liver.

Question 73

Hepatic angiosarcomas are associated with what carcinogen exposures?

Answer 73

Hepatic angiosarcomas are associated with carcinogen exposures, including:

• arsenic (arsenical pesticides),
• Thorotrast (a radioactive contrast agent formerly used for radiologic imaging), and
• polyvinyl chloride (a widely used plastic).

All of these agents have long latent periods between
initial exposure and eventual tumor development. The increased frequency of angiosarcomas
among polyvinyl chloride workers is one of the well-documented instances of human chemical
carcinogenesis.

Question 74

Angiosarcomas arise in the setting of lymphedema?

True or False

Answer 74

True

Angiosarcomas can also arise in the setting of lymphedema, classically in the ipsilateral upper
extremity several years after radical mastectomy(i.e., with lymph node resection) for breast
cancer; the tumor presumably arises from lymphatic vessels (lymphangiosarcoma).

Angiosarcomas have also been induced by radiation and are rarely associated with foreign
material introduced into the body either iatrogenically or accidentally.

Answer 75

Cutaneous angiosarcomas can begin as deceptively small, sharply
demarcated, asymptomatic, often multiple red nodules; most eventually become large, fleshy
masses of red-tan to gray-white tissue ( Fig. 11-33A ). The margins blend imperceptibly with
surrounding structures. Central areas of necrosis and hemorrhage are frequent.

Question 76

What is the morphology of cutaneous angiosarcoma?

Answer 76

Cutaneous angiosarcomas can begin as deceptively small, sharply demarcated, asymptomatic, often multiple red nodules; most eventually become large, fleshy
masses of red-tan to gray-white tissue ( Fig. 11-33A ).

The margins blend imperceptibly with
surrounding structures.

Central areas of necrosis and hemorrhage are frequent.

Question 77

What is the microscopic appearance of Angiosarcoma?

Answer 77

Microscopically, all degrees of differentiation can be seen, from plump, anaplastic but
recognizable endothelial cells producing vascular channels ( Fig. 11-33B ) to wildly
undifferentiated tumors with a solid spindle cell appearance and without definite blood
vessels.

Question 78

Angiosarcomas can be demonstrated by staining for what factor?

Answer 78

CD31 or von Willebrand factor

Question 79

What is the clinical feature of Angiosarcomas?

Answer 79

angiosarcomas are locally invasive and can metastasize readily.

Angiosarcomas are
aggressive tumors with current 5-year survival rates approaching 30%.

Question 80

What are Hemangiopericytomas?

Answer 80

Hemangiopericytomas are rare tumors derived from pericytes—myofibroblast-like cells that are
normally arranged around capillaries and venules.

Question 81

What is the course of Hemangiopericytomas?

Answer 81

Hemangiopericytomas can occur as slowly
enlarging, painless masses at any anatomic site, but are most common on the lower extremities
(especially the thigh) and in the retroperitoneum.

Question 82

What anatomic site is hemangiopericytoma most commonly found?

Answer 82

but are most common on the lower extremities
(especially the thigh) and in the retroperitoneum.

Question 83

Hemangiopericytoma is composed of what?

Answer 83

They consist of numerous branching capillary
channels and gaping sinusoidal spaces enclosed within nests of spindle-shaped to round cells.

Special stains confirm that these cells are outside the endothelial cell basement membrane and
are therefore pericytes.

The tumors may recur after excision, and roughly half will metastasize, usually hematogenously to lungs, bone, or liver.