Kidney tumor

Benign/borderline adult tumors


Last author update: 3 January 2022
Last staff update: 6 January 2022

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PubMed Search: Hemangioma kidney [TIAB] "last 5 years"[dp]

Bitania Wondimu, M.D.
Maria Tretiakova, M.D., Ph.D.
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Cite this page: Wondimu B, Tretiakova M. Hemangioma. website. Accessed October 2nd, 2023.
Definition / general
  • Benign vascular proliferation, rarely diagnosed in kidney (more common in skin or superficial soft tissue)
  • Subtypes: capillary, cavernous, mixed, anastomosing
Essential features
  • Benign, circumscribed, unencapsulated proliferation of capillaries with endothelial lining in kidney
  • Can appear radiologically similar to renal cell carcinomas, angiosarcomas or other malignancies (Arch Pathol Lab Med 2020;144:240)
  • Anastomosing hemangioma: sinusoidal vessels with anastomotic arrangement, hobnail endothelial cells, with or without extramedullary hematopoiesis (Histopathology 2014;65:309)
  • Benign, neoplastic vascular proliferation
  • Pelvis or medullary pyramid, rarely in renal cortex or capsule
  • Hemangiomas more commonly found in skin or soft tissues
  • Often associated with end stage renal disease (Histopathology 2014;65:309)
  • Can be associated with acquired cystic kidney disease, polycythemia or renal cell carcinoma
Clinical features
  • Typically asymptomatic but can present with hematuria or flank / abdominal pain
  • Often incidentally found on imaging
  • May be associated with vascular malformation syndromes, including Klippel-Trenaunay and Sturge-Weber (Virchows Arch 2012;461:669)
  • May be diagnosed radiologically but can be difficult to distinguish from renal cell carcinoma or other tumors on imaging
  • Diagnosis often made on biopsy or nephrectomy (Radiol Case Rep 2019;14:750)
Radiology description
  • Nonspecific echogenicity on ultrasound
  • CT: hypoattenuation, arterial enhancement, can be concerning for malignancy
  • Difficult to distinguish radiographically from malignant lesions; biopsy or excision often needed for definitive diagnosis (Radiol Case Rep 2019;14:750)
Radiology images

Images hosted on other servers:

Kidney ultrasound

Noncontrast CT

Contrast CT

Prognostic factors
  • Excellent prognosis with excision
Case reports
  • May regress spontaneously (J Urol 2002;167:488)
  • Variable; can include no treatment, endoscopic ablation or nephrectomy (Am J Case Rep 2017;18:255)
  • In healthy patients with minimal symptoms and confirmed diagnosis, observation favored
  • Nephrectomy often occurs when difficult to distinguish from carcinoma
Gross description
  • Unilateral, solitary, well circumscribed, red to brown mass
  • Most commonly present in papillary tips; can also be found in submucosa, medulla (Am J Surg Pathol 2010;34:942)
Microscopic (histologic) description
  • Circumscribed, unencapsulated proliferation of irregular, blood filled vascular spaces lined by a single layer of endothelial cells
  • May or may not show lobular growth pattern with large feeding vessels at periphery (Virchows Arch 2012;461:669)
  • Multiple subtypes:
    • Capillary: more common, characterized by slit-like vascular spaces
    • Cavernous: characterized by dilated vessels
    • Mixed: features of both capillary and cavernous
    • Anastomosing hemangioma (variant of capillary)
  • Anastomosing hemangioma (AH):
    • Capillary sized sinusoidal vessels with anastomotic arrangement
    • Scattered hobnail endothelial cells
    • Extramedullary hematopoiesis, fibrin thrombi, extensive perirenal fat entrapment, intravascular growth and mast cells may be seen (Histopathology 2014;65:309)
  • Cytologic atypia and mitotic activity rare
  • Regressive changes, including hyalinization, cystic changes and fatty overgrowth (Histopathology 2014;65:309)
Microscopic (histologic) images

Contributed by Maria Tretiakova, M.D., Ph.D. and AFIP images

Cavernous hemangioma

Hypocellular AH

Anastomosing hemangioma

Sinusoidal anastomosing pattern

Fibrin thrombi (AH)

Extramedullary hematopoiesis

CD31 (AH)

Renal hemangioma

Sample pathology report
  • Left kidney, radical nephrectomy:
    • Anastomosing hemangioma (1.3 cm) (see comment)
    • Comment: The tumor is a well circumscribed, low grade vascular neoplasm composed of small capillary channels in an anastomosing pattern. There is no nuclear atypia or significant mitotic activity. In addition, foci of extramedullary hematopoiesis and fibrin thrombi are present. Immunohistochemistry is positive for CD31, supporting the diagnosis of a vascular neoplasm. The morphologic and immunohistochemical profile of the neoplasm is consistent with anastomosing hemangioma.
Differential diagnosis
Board review style question #1

The tumor in the above image is found in the kidney and is negative for cytokeratins on immunohistochemistry. What is the diagnosis?

  1. Anastomosing hemangioma
  2. Kaposi sarcoma
  3. Renal cell carcinoma
  4. Well differentiated angiosarcoma
Board review style answer #1
A. Anastomosing hemangioma. Vascular lesion in the kidney with anastomosing sinusoidal-like vascular spaces and absent / minimal atypia of endothelial cells most likely to be anastomosing hemangioma. Kaposi sarcoma more likely to be seen in dermis or subcutaneous tissue. Angiosarcoma would demonstrate more atypial cytologic features and endothelial cell multilayering. Renal cell carcinomas can have vascular rich areas but would stain for cytokeratins.

Comment Here

Reference: Hemangioma
Board review style question #2

A 42 year old woman with end stage renal disease presents with a renal mass. Excision of the lesion reveals the above vascular lesion. Which of the following is true concerning this lesion?

  1. Cytologic atypia and mitotic activity is common
  2. Extramedullary hematopoiesis, fibrin thrombi and mast cells may be present
  3. Lesion will be positive for cytokeratins and CD10
  4. Prognosis is poor
Board review style answer #2
B. Extramedullary hematopoiesis, fibrin thrombi and mast cells may be present. Cytologic atypia and mitotic activity is rare and prognosis after excision is excellent. Cytokeratins and CD10 would be positive in renal cell carcinoma but negative in anastomosing hemangioma.

Comment Here

Reference: Hemangioma
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