#dermpathJC March 2020 summary

#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

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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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Memorable tweets:

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

With love,

DermpathJC

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