Vascular Tumors

Benign Tumors: Common Types - Vessel Buddies

• Hemangioma: Most common.
  • Capillary: Closely packed capillaries.
    • Strawberry (Juvenile): Infants, regresses. Skin.
    • Cherry (Senile): Adults, ↑ age. Trunk.
  • Cavernous: Large, dilated channels. Liver, brain. Risk of bleed. Von Hippel-Lindau (VHL) assoc.
• Lymphangioma: Lymphatic channels.
  • Capillary (Simple): Small channels. Head, neck, axilla.
  • Cavernous (Cystic Hygroma): Large cysts. Neck, axilla. Turner syndrome.
• Glomus Tumor: Painful, red-blue nodule under nails. From glomus body smooth muscle cells (thermoregulation).
• Bacillary Angiomatosis: Immunocompromised (HIV). Bartonella spp. (e.g., B. henselae).
• Pyogenic Granuloma: Polypoid, red, bleeds. Skin, oral mucosa (gingiva). Rapid growth. Trauma, pregnancy.

⭐ Cystic hygroma (cavernous lymphangioma) is frequently associated with Turner syndrome (45,X0).

Benign Tumors: Special Forms - Unique Bloomers

• Glomus Tumor:
  • Painful, small, red-blue nodule, often under fingernails.
  • Origin: Modified smooth muscle cells of glomus body (thermoregulatory).
  • Key feature: Paroxysmal pain triggered by cold/pressure.
• Bacillary Angiomatosis:
  • Etiology: Bartonella henselae or B. quintana.
  • Population: Immunocompromised individuals (esp. HIV/AIDS).
  • Clinical: Red to purple papules/nodules; can involve skin, bone, brain, other organs.
  • Histology: Neutrophilic infiltrate; organisms seen with Warthin-Starry stain.
• Pyogenic Granuloma (Lobular Capillary Hemangioma):
  • Rapidly growing, friable, red, often pedunculated lesion.
  • Common sites: Skin (fingers), oral mucosa (gingiva - esp. during pregnancy: "granuloma gravidarum").
  • Often history of trauma.

⭐ Bacillary Angiomatosis is caused by Bartonella species and is crucial to differentiate from Kaposi sarcoma in immunocompromised patients; Warthin-Starry stain is diagnostic, revealing the bacilli.

Intermediate Tumors: Borderline - Edge Riders

• Locally aggressive neoplasms; potential for recurrence & metastasis is low but present.

• Kaposi Sarcoma (KS)

  • Etiology: Human Herpesvirus-8 (HHV-8 / KSHV) infection, particularly in immunocompromised states.
  • Key Features: Proliferation of spindle cells forming slit-like vascular spaces, extravasated red blood cells, hemosiderin deposition.
  • Types:
    • Classic (elderly, indolent)
    • Endemic African (aggressive)
    • Transplant-associated
    • AIDS-associated (epidemic, most common HIV-related malignancy).
  • IHC: CD31, CD34, LANA-1 (for HHV-8).
  • 

• Hemangioendothelioma

  • Spectrum of borderline vascular tumors.
  • Epithelioid Hemangioendothelioma (EHE)
    • Cells: Epithelioid endothelial cells, often with intracytoplasmic lumina/vacuoles (blister cells).
    • Genetics: Characteristic WWTR1-CAMTA1 or YAP1-TFE3 gene fusions.
    • Behavior: Can be indolent or aggressive; metastasizes in ~20-30% of cases.

    ⭐ EHE commonly involves multiple nodules in organs like the liver or lungs at presentation, mimicking metastatic carcinoma.

Malignant Tumors: Angiosarcoma - Angio Invaders

• Definition: Aggressive malignant tumor of endothelial cell origin.
• Common Sites:
  • Skin (esp. scalp, face of elderly; UV exposure).
  • Soft tissue, breast, liver, spleen, bone.
• Etiology & Associations:
  • Chronic lymphedema (📌 Stewart-Treves syndrome: post-mastectomy).
  • Radiation therapy.
  • Chemical carcinogens:
    • Vinyl chloride (liver angiosarcoma).
    • Arsenic, Thorotrast.
  • Foreign bodies (e.g., Dacron grafts).
• Morphology:
  • Gross: Ill-defined, hemorrhagic, infiltrative lesions; from red patches to fleshy masses.
  • Micro: Variable; anastomosing vascular channels lined by atypical, pleomorphic endothelial cells to solid sheets of anaplastic/spindle cells. "Dissection of collagen".
• Immunohistochemistry (IHC):
  • Positive for endothelial markers: CD31 (key), CD34, Factor VIII (vWF), ERG (nuclear).
• Prognosis: Poor; locally aggressive with high rates of recurrence & metastasis (lungs, liver).

⭐ Hepatic angiosarcoma is strongly associated with exposure to vinyl chloride, arsenic, and Thorotrast.

High‑Yield Points - ⚡ Biggest Takeaways

• Kaposi Sarcoma: HHV-8 association, common in AIDS; features slit-like vascular spaces.
• Bacillary Angiomatosis: Bartonella infection in immunocompromised individuals; neutrophilic infiltrate is key.
• Angiosarcoma: Malignant endothelial tumor; linked to radiation, chronic lymphedema (Stewart-Treves), vinyl chloride.
• Hemangiomas: Benign vascular tumors; strawberry type (infantile) often regresses, cavernous type common.
• Glomus Tumor: Painful, benign lesion, typically subungual; arises from glomus body cells.
• Pyogenic Granuloma: Rapidly growing benign polypoid capillary hemangioma; linked to trauma, pregnancy.
• Cystic Hygroma: Lymphangioma variant, often in neck (posterior triangle); associated with Turner syndrome (45,X0).