Table of Contents
Definition / general | Etiology | Clinical features | Case reports | Prognosis and treatment | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Pernick N. Angiomyolipoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/smallbowelangiomyolipoma.html. Accessed December 16th, 2019.
Definition / general
- Benign triphasic tumor composed of dysmorphic, thick walled blood vessels, smooth muscle that appears to spin off from vessel walls and mature lipid distended cells
Etiology
- Member of PEComa family, a concept first proposed by Bonetti (Am J Surg Pathol 1992;16:307), which comprises mesenchymal tumors with perivascular clear cells and epithelioid features that coexpress melanocytic and muscle markers
- Occasionally associated with tuberous sclerosis (OMIM: Tuberous Sclerosis 1 [Accessed 16 February 2018])
Clinical features
- Usually arises in the kidney (eMedicine: Kidney Angiomyolipoma Imaging [Accessed 16 February 2018]) or occasionally in the liver (Arch Pathol Lab Med 2008;132:1679)
- Gastrointestinal angiomyolipoma is very rare
Case reports
- First documented case of symptomatic ileal angiomyolipoma was in a 60 year old woman suffering from intermittent periumbilical pain (Korean J Gastroenterol 2000;36:250)
- Second case of ileal angiomyolipoma occurred in a 48 year old woman with vague abdominal pain and bloody stool (J Gastroenterol 2005;40:200)
- 28 year old man with with ileal intussusception (World J Gastroenterol 2009;15:1398)
Prognosis and treatment
- Typically benign behavior at other sites but occasionally is invasive with metastases (Am J Surg Pathol 1991;15:1083)
Microscopic (histologic) description
- Benign triphasic tumor composed of dysmorphic, thick walled blood vessels, smooth muscle that appears to spin off from vessel walls and mature lipid distended cells
- Tumors occasionally have bizarre epithelioid smooth muscle cells (Int J Surg Pathol 2000;8:67) and possible multinucleation
Positive stains
Negative stains
Differential diagnosis
- Theoretically broad, encompassing smooth muscle and lipogenic tumors but narrowed when one carefully identifies the components of the tumor; few other tumors are immunoreactive for both smooth muscle and melanocytic markers
- Leiomyomas and leiomyosarcomas have a prominent smooth muscle component but lack a prominent vascular or adipose component
- Melanomas have prominent atypia, necrosis and infiltrative borders
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