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Soft Tissue Tumors Part 3 - Muscle, Vascular, Nerve, Other
Benign vascular tumors
Microvenular hemangioma
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Revised: 31 October 2009, last major update October 2009
Copyright: (c) 2002-2009, PathologyOutlines.com, Inc.
Definition
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● Dermal proliferation of small, irregular branching capillaries and venules with inconspicuous lumina
Terminology
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● First described in 1989 as microcapillary hemangioma (Z Hautkr 1989;64:1071), and in 1991 with current terminology (J Cutan Pathol 1991;18:235)
Epidemiology
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● Rare, < 50 cases reported
● Young to middle aged adults
Sites
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● Often trunk or limbs
Etiology
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● May be form of acquired venous hemangioma
● Microcapillary hemangioma: similar histology, but occurs in young women taking oral contraceptives or during pregnancy
Clinical features
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● Presents as slow growing, solitary, asymptomatic, purple-red papule or plaque
Case reports
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● 23 year old Japanese woman (Pathol Int 1998;48:237)
● 28 year old man with thigh nodule (Case of the Week #80)
● 40 year old woman (Dermatology 2003;206:161)
● 55 year old woman with POEMS syndrome and HHV8+ microvenular hemangioma (Archives 2003;127:1034)
Treatment
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● Excision is curative
Gross images
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Well defined, oval red lesion
Dermoscopic description
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● Multiple well-demarcated red globules; fine pigment network at periphery (Dermatology 2007;215:69)
Microscopic description
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● Dermal proliferation of small, irregular branching capillaries and venules with inconspicuous lumina
● Endothelial cells may be plump, but no atypia
● Stroma is collagenous
● Variable lymphocytes
● No fat invasion, although may grow along collagenous septa of subcutis
● No spindle cells
Micro images
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Case of the Week images
Dermal vascular proliferation
HHV8+ tumor
Positive stains
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● Endothelial cells - CD34, CD31, Factor VIII related antigen, vWF, Ulex europaeus lectin
● Pericytes - smooth muscle actin
Negative stains
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● Podoplanin (Pathol Res Pract 2008;204:817), HHV8
Differential diagnosis
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● Acquired (tufted) angioma: multiple vascular lobules similar to pyogenic granuloma but more cellular, resembling cannonballs
● Kaposi's sarcoma-patch stage: irregular vascular spaces are anastomosing but not collapsed, and are accompanied by atypical endothelial cells, eosinophilic hyaline globules, plasma cells and fascicles of spindle cells; may be irregular dissection of collagen bundles by vessels; spindle cells are HHV8+, patients are HIV+ (AJCP 2004;121:335)
● Kaposiform hemangioendothelioma: also has slit-like lumina, but they are due to nodules and sheets of compact spindle cells; affects the skin or retroperitoneum of infants and children, may be associated with severe coagulopathy
● Sclerosing hemangioma
● Statis related change
End of Soft Tissue Tumors Part 3 - Muscle, Vascular, Nerve, Other > Microvenular hemangioma
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