#dermpathJC March 2020:

Thursday, March 26th, 9 pm EST

Article discussed: Angiosarcoma, Radiation-Associated Angiosarcoma, and Atypical Vascular Lesion

Authors: David R. Lucas

Open access courtesy of Archives of Pathology and Laboratory Medicine: https://www.archivesofpathology.org/doi/pdf/10.1043/1543-2165-133.11.1804

Summary prepared by: Cacey Peters, M.D. (@caceypeters)

Journal Club Summary:

Angiosarcoma general points:

• 1% of soft tissue sarcomas
• Associated with radiation therapy, most often breast cancer
  • Also associated with chronic lymphedema, toxins (i.e. vinyl chloride), and foreign bodies (i.e. A/V fistulas)
• Usually presents as sporadic cutaneous tumor on scalp/face of elderly
• Reported in every anatomic site
• Bruise-like area that ulcerates or becomes nodular
• Often have smaller satellite lesions peripherally
• Clinically aggressive with high morbidity, regardless of grade
  • Prognosis in sporadic cutaneous angiosarcoma correlates with high- and low- risk groups on the basis of age, epitheliod histology, necrosis, and tumor depth
• Deep tumors can be hemorrhagic spongelike or microcystic with necrosis
• Well-differentiated lesions can be deceptively bland, but will have some combination of hyperchromasia, mild pleomorphism, prominent nucleoli, mitotic figures, multilayering, and/or dermal collagen entrapment forming intraluminal papillary structures
• Surgical margins may be obscured by atypical lymphatic/capillary proliferations
• Moderate/poorly differentiated types will often have heterogeneous cytoarchitectural features
  • Some combination of epithelioid, spindled, or pleomorphic cytology
  • Some combination of vasoformative, sieve-like, kaposiform, or solid architecture
• Undifferentiated angiosarcoma will need immunohistochemistry to confirm the diagnosis
  • CD31 = single best marker with high sensitivity and specificity
    • Diffuse, intense staining with membranous accentuation
    • Can be hard to interpret due to background blush, staining macrophages, and low-level expression in other tumor types
  • CD 34 and factor VIII = present in most angiosarcomas but not reliably in poorly differentiated
  • Cytokeratin pitfall = found in 35% of cases in one study (especially epithelioid angiosarcoma) although usually focal

Radiation-associated angiosarcoma

• Clinically and morphologically similar to sporadic angiosarcoma
  • Latency is shorter for breast angiosarcoma
    • 5-7 years on average
    • Significant occurrence in less than 3 years which questions the 3-year rule
  • More often cutaneous than sporadic angiosarcoma
    • Erythematous plaque/patch/nodules with edema
    • Diffuse, multifocal, and extensive involvement of the breast is common
    • Median size = 7.5 cm

Atypical Vascular Lesion (AVL):

• Benign course; can recur; rarely progress to angiosarcoma
• Tendency to develop further lesions, commonly AVLs
• Present as 1 or more small, flesh-colored papules or erythematous patches arising in radiated skin
• Histologically difficult to distinguish from well-differentiated angiosarcoma in a biopsy
• Often resemble lymphangiomas
  • Well-demarcated proliferation of thin walled, dilated, interanastomosing channels without erythrocytes
  • Lined by attenuated or hobnail endothelial cells without atypia
• Can resemble lymphangioendothelioma, lymphangioma circumscriptum, or both within the same lesion
• Most are limited to the superficial and mid dermis
• Current recommendations are to completely excise and follow for recurrence

Vascular-type AVL

• First described in 2005 with 3 cases that resemble lobular capillary hemangioma in mammary skin after radiation
  • All 3 cases developed angiosarcoma
• In 2008, 8 more cases were described where only one developed angiosarcoma

It is suggested that vascular-type AVL is more likely to progress to angiosarcoma than the more common lymphatic-type AVL

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Stay safe my friends, and we will see you next month for another dermpath journal club,

With love,

DermpathJC