Vascular tumors can be benign, intermediate, or malignant. Benign tumors include hemangiomas which are localized collections of blood vessels. Capillary hemangiomas are common in infants and usually regress by age 7. Cavernous hemangiomas contain large blood-filled spaces. Lymphangiomas are lymphatic system analogs. Benign glomus tumors arise from specialized cells and cause pain. Kaposi sarcoma is an intermediate tumor associated with HHV-8 and can range from indolent to aggressive depending on subtype. Malignant tumors include angiosarcomas, which demonstrate invasion and metastasis and have a poor prognosis. Hemangiopericytomas also have potential for malignant behavior.

1. Vascular Tumors
BENIGN TUMORS AND TUMOR-LIKE CONDITIONS :
Hemangioma:
 Most commonly are localized, however some
involve large segments of body such as
an entire extremity (called angiomatosis).
 The majority are superficial lesions (head or neck),
but may occur internally (one third in liver).
 Malignant transformation occurs rarely if at all.
 Constitute 7% of all benign tumors
in infancy and childhood.

2. Capillary Hemangioma:
 Skin , subcutaneous tissues, and mucous
membranes of oral cavities and lips.
 May also occur in liver, spleen, and kidneys.
 The "strawberry type" of capillary hemangioma
(juvenile hemangioma) of skin of newborn:-
o Extremely common (1 in 200 births).
o May be multiple.
o Grow rapidly in first few months.
o Begin to fade when the child is between ages
1 and 3 years.
o Regress by age 7 in 75% to 90% of cases.

3. Morphology:
 Gross:
o Size : few millimeters to several centimeters.
o Bright red to blue.
o Level with surface of skin or slightly elevated.
o Occasionally, they are pedunculated.
 Microscope :
o Closely packed thin-walled capillaries which are
blood-filled and lined by flattened endothelium,
separated by scanty connective tissue stroma.

4. Infantile capillary hemangioma ,
Photograph shows a strawberry-colored
lesion and swelling of left cheek.
capillary hemangioma: numerous
thin-walled blood-filled capillaries are
seen in upper dermis(H&E).

5. Cavernous Hemangioma:
 Less common than capillary variety.
 Usually larger, less well circumscribed, and
more involve deep structures.
 Locally destructive and show no tendency to regress.
 Those in brain are most threatening.
 In von Hippel-Lindau disease: cavernous
hemangiomas in cerebellum, brain stem, and eye;
along with cystic neoplasms in pancreas and liver.

6. Morphology:
 Gross:
o Red-blue, soft, spongy mass 1 to 2 cm in diameter.
o Rarely giant forms.
 Microscope:
o Large cavernous vascular spaces,
partly or completely filled with blood,
separated by scanty connective tissue stroma.
o Intravascular thrombosis with associated
dystrophic calcification is common.

8. Pyogenic Granuloma (Lobular Capillary Hemangioma):
 Exophytic red nodule attached by a stalk to skin
and gingival or oral mucosa.
 Bleeds easily and often ulcerated.
 One third of lesions develop after trauma.
 Histologicaly : lobules of proliferating capillaries ,
accompanied by extensive edema, and acute and
chronic inflammatory infiltrate; resembling
exuberant granulation tissue.
 Recurrence occurs infrequently.

9.  Granuloma gravidarum:
o Pyogenic granuloma that occurs in gingiva of
1% of pregnant women.
o Regresses after delivery.
o Highlight the role of estrogen in vascular growth
and proliferation.
pyogenic granuloma of index finger well developed lobular pattern.

10. Lymphangiomas:
Lymphatic analog of hemangiomas of blood vessels.
Capillary Lymphangioma:
 Occur subcutaneously in head and neck and in axilla.
 Slightly elevated or pedunculated lesions,
1 to 2 cm in diameter, blister-like blebs that are
filled with exudate.
 Histologically: network of endothelium-lined lymph
spaces beneath epidermis and distinguished from
capillary hemangioma only by absence of blood cells.

11. Capillary Lymphangioma

12. Cavernous lymphangioma (Cystic hygroma):
 Occurs in children in neck or axilla, rarely
retroperitoneally.
 Occasionally achieve considerable size (up to 15 cm).
 Massively dilated cystic lymphatic spaces lined by
endothelial cells and separated by scant intervening
connective tissue stroma that often contains
lymphoid aggregates.
 Cystic hygroma of neck occur in Turner syndrome .

13. Cystic Hygroma

14. Glomus Tumor (Glomangioma):
 Benign painful tumor.
 Arise from modified smooth muscle cells of
glomus body (a specialized arteriovenous
anastomosis that is involved in thermoregulation).
 Most commonly found in distal portion of digits,
especially under fingernails.
 Excision is curative.
Morphology:
 Gross:
o Usually small (under 1 cm in diameter).
o Slightly elevated, rounded, red-blue, firm nodules.

15.  Microscope :
o Branching vascular channels separated by
connective tissue stroma.
o The stroma contains aggregates, nests,
and masses of specialized glomus cells that
typically arranged around vessels.
o Individual cells are small, regular in size, round
or cuboidal, with scant cytoplasm and features
very similar to smooth muscle cells on electron
microscopy.

17. Vascular Ectasias:
 Not true neoplasms.
 Include group of lesions characterized by
localized dilation of preexisting vessels.
Nevus Flammeus:
 Birth mark.
 Most common form of ectasia.
 Head and neck.
 Flat and color (light pink to deep purple).
 Histologically: dilation of vessels in dermis.
 The majority ultimately fade and regress.

18.  Special form of nevus flammeus (port-wine stain):
o Grow proportionately with child.
o Thicken the skin surface.
o No tendency to fade.
Spider Telangiectasia (Arterial Spider):
 Pulsatile dilated subcutaneous arteries or arterioles.
 Blanches when pressure is applied.
 Face , neck, and upper chest.
 Most frequent in pregnant women
and in patients with liver cirrhosis.
 Hyperestrinism found in these two
settings is believed to play a role.

19. Hereditary Hemorrhagic Telangiectasia
(Osler-Weber- Rendu Disease):
 Autosomal dominant disease.
 Genetic malformations consisting
of dilated capillaries and veins.
 Present from birth and distributed
over skin and mucous membranes
of oral cavity, lips, respiratory, GIT,
and urinary tracts.
 Rupture may occur causing serious nosebleeds,
bleeding into gut, or hematuria.

20. Bacillary Angiomatosis :
 First described in AIDS patients.
 An opportunistic infection manifest as vascular
proliferations that clinically resemble tumors.
 Involve skin, bone, brain, and other organs.
 Caused by infection with gram-negative bacilli
of Bartonella family (Bartonella henselae, and
B. quintana).
 These bacilli are difficult to be cultivated in lab.
 Can be demonstrated by molecular methods
(polymerase chain reaction ).
 How these organisms cause vessel lesions is unclear.

21. Morphology:
 Gross : cutaneous one to numerous red papules
and nodules, or rounded subcutaneous masses.
 Microscope :
o Proliferation of capillaries that exhibit epithelioid
endothelial cells with nuclear atypia and mitoses.
o Numerous stromal neutrophils, nuclear dust , and purplish
granular material consisting of causative bacteria.

22. INTERMEDIATE-GRADE (BORDERLINE, LOW-GRADE
MALIGNANT) TUMORS:
Kaposi Sarcoma:
Four forms :
 Chronic, classic , or European KS:
o Occurs primarily in older men of Eastern Europe.
o Not associated wth HIV.
o Remain asymptomatic and localized to skin and
subcutaneous tissue.
o Viscera or mucosa involved only in 10% of patients.

23.  Lymphadenopathic:
o Also called African or endemic KS.
o Common in Africa.
o Skin lesions are sparse.
o HIV-negative and HIV-positive cases occur.
 Transplant-associated(immunosuppression-associated)KS:
o Occurs several months to few years postoperatively.
o Aggressive.
o Involving lymph nodes, mucosa, and visceral organs
in half of patients.
o Skin lesions may be absent.
 AIDS-associated KS:
o Involvement of lymph nodes and gut and wide
dissemination occur early in course.

24. Morphology:
Three stages identified: patch, plaque, and nodule.
 Patch stage:
o Pink to red to purple solitary or multiple macules
that are confined to distal lower extremities or feet.
o Microscopically: dilated, irregular, and angulated
blood vessels lined by endothelial cells ; with
interspersed infiltrate of lymphocytes, plasma cells,
and macrophages.

25.  Plaque stage:
o Over time lesions spread proximally and
convert into larger, violaceous, raised plaques.
o Microscopically:
 Dermal dilated jagged vascular channels
lined by plump spindle cells with perivascular
aggregates of similar spindled cells.
 Scattered between vascular channels are
extravasated red blood cells, hemosiderin-laden
macrophages, lymphocytes, and plasma cells.
 Pink hyalin globules of uncertain nature in
spindled cells and macrophages.
 Mitotic figures may be present.

26.  Nodule stage:
o At still later stage , lesions become nodular
and more neoplastic.
o Microscopically:
 Sheets of plump proliferating spindle cells
in dermis or subcutaneous tissues.
 In this cellular background are scattered small
vessels and slit-like spaces that contain red cells.
 Marked hemorrhage, lymphocytes, and macrophages
may be admixed with this cellular background.
 Mitotic figures are common, as are the round pink
cytoplasmic globules.
o Often accompanied by involvement of lymph nodes
and viscera.

27. Microscopy shows spindle cells and slit like vascular
channels containing erythrocytes (H & E ×400)

29. Pathogenesis:
 In 1994, DNA fragments of a previously unrecognized
herpesvirus (Human Herpes Virus 8 [HHV-8] also
known as KS-associated Herpes Virus [KSHV])
isolated from skin lesion of patient with AIDS.
 Subsequent studies have shown that regardless of
clinical subtype 95% of KS lesions are infected with
KSHV.
 KSHV is transmitted sexually and by poorly
understood nonsexual routes.
 KSHV proteins disrupt the control of cellular
proliferation and prevent apoptosis of endothelial
cells, through production of p53 inhibitors and
a viral homologue of cyclin D.

30. Clinical Course:
 Classic form of KS: resection of primary lesions
and recurrences is usually an adequate treatment,
yielding an excellent prognosis.
 Radiation: for multiple lesions in a restricted area.
 Chemotherapy: for extensive or disseminated disease.
 In immunosuppression-associated KS: withdrawal
or reduction of immunosuppression, supplemented
with chemotherapy or radiotherapy is often effective.
 In persons with AIDS: antiretroviral therapy.

31. Hemangioendothelioma:
 Representative of this group is epithelioid
hemangioendothelioma:
o Vascular tumor occurring around medium-sized
and large veins in soft tissue of adults.
o Well-defined vascular channels are inconspicuous,
and tumor cells are plump and often cuboidal,
thus resembling epithelial cells.
o Clinical behavior is variable: most are cured by
excision, but 40% recur, 20% to 30% metastasize,
and 15% of patients die of the tumors.

32. Epitheliod hemangioendothelioma of liver,
the epithelioid tumor cells grow within dilated
sinusoids with intervening collagenous fibrosis.
The tumor cells of epithelioid
hemangioendothelioma grow in sinusoids
(long arrows) among non-neoplastic
hepatocytes as shown by
Immunohistochemical staining for Hep-Par1
(arrowhead).

33. MALIGNANT TUMORS:
Angiosarcoma:
 Varying from highly differentiated tumors that
resemble hemangiomas (hemangiosarcoma) ;
to those difficult to distinguish from carcinoma
or melanoma.
 Occur in both sexes, more often in older adults.
 Anywhere in body but most commonly in skin,
soft tissue, breast, and liver.
 Hepatic angiosarcomas are associated with
carcinogens: arsenic , Thorotrast , and polyvinyl
chloride (PVC).

34.  May also arise in setting of lymphedema 10 years
following radical mastectomy for breast cancer.
 In such cases, the tumor arises from dilated
lymphatic vessels (lymphangiosarcoma).
 Angiosarcomas can be induced by radiation.
 May be associated with foreign material introduced
into body (either iatrogenically or accidentally).
 Clinically, angiosarcomas show local invasion and
distal metastasis.
 The majority of patients have poor outcome with
very few surviving 5 years.

35. Morphology:
 Gross :
o Cutaneous angiosarcoma may begin as small,
sharply demarcated, asymptomatic, often multiple
red nodules.
o Eventually most such tumors become large fleshy
masses of pale gray-white soft tissue.
o The margins blend with surrounding structures.
o Central softening and areas of necrosis and
hemorrhage are frequent.

36.  Microscope :
o All degrees of differentiation may be found.
o From those that are vascular lined with plump,
anaplastic endothelial cells.
o To tumors that are quite undifferentiated,
produce no definite blood vessels, markedly atypical,
and have solid spindle cell appearance.
o Endothelial cell derivation is demonstrated by
immunostaining for CD31, CD34, or vWF .

37. Angiosarcoma on Chest
High-grade angiosarcoma. The tumor demonstrates diffuse
cytologic atypia and a combination of irregular vasoformative and
solid growth.
High-grade angiosarcoma ,
At high power, the widespread
nuclear hyperchromasia and
pleomorphism are easily seen, as
are the numerous mitotic figures.

38. Hemangiopericytoma:
 Neoplasms with a grossly fleshy or spongy
consistency ; and a thin-walled branching
("staghorn") vascular pattern microscopically.
 Derived from pericytes (the cells normally arranged
along capillaries and venules).
 Arise as slowly growing masses in retroperitoneum
or lower extremities (especially thigh) of
middle aged women.
 Reaching 5 to 15 cm in maximum diameter.
 Two-thirds have a benign course, but one-third
are malignant.
 Presence of necrosis, high mitotic rate, and
nuclear pleomorphism, especially in a large tumor,
is associated with aggressive behavior.

39. Hemangiopericytoma -
Thigh - Gross specimen Hemangiopericytoma: showing stag-horn appearance