Pathology of Pyogenic Granuloma -(Lobular Capillary Hemangioma)
[Lobular capillary hemangiomas - a group of vascular lesions characterized by capillary sized
vessels arranged in lobules. ]
Pyogenic granuloma is a polypoid form of capillary hemangioma which was previously considered to be part of a reactive or infective process.
Later studies suggest that it represents neoplastic vascular proliferation.
Cause: Following trauma ; retinoid therapy ; insect bite ; burn ; cryotherapy ; hormonal factor ; underlying arteriovenous malformation.
Age: Usually occurs in children and young adults.
Site: It is a vascular lesion of the skin and mucous membrane. Common sites include face, finger, mucous membrane of oral cavity (gingiva, lips, tongue, buccal mucosa, and palate).
Several cases have been reported in the nasal cavity. Pyogenic granuloma arising from the nasal septum may be associated to nasal intubation as the triggering agent.
Other less common sites are trunk, arms, leg, external genitalia, conjunctiva, cornea, larynx.
Pyogenic granuloma has been reported throughout the gastrointestinal tract.
Clinically, these are polypoid or pedunculated, reddish brown nodules usually less than 2cm in diameter.
Often the surface of the lesions are ulcerated and bleeds easily.
Variants: Disseminated; Intravenous ; Subcutaneous ; Medication induced - following retinoid therapy ; 'Pregnancy tumour' (epulis gravidarum)- Pyogenic granuloma often develops during pregnancy.
Histopathology Image of Pyogenic Granuloma.
Microscopically, this is an exophytic, often ulcerated lesion characterized by lobulated proliferation of capillary sized vessels in a loose and oedematous stroma.
The surface epithelium is attenuated and at the margin an epidermal collarette is formed by elongated rete ridges .
Normal mitotic figures may be present.
Extramedullary hematopoiesis has been reported in the stroma.
Kaposi's sarcoma-like pyogenic granuloma: Exophylic growth pattern ; well circumscribed; lobular nodules made up of fascicular arrangements of spindle cells and slit-like vessels.
Well differentiated angiosarcoma (poor circumsription, cellular pleomorphism and dissection of collagen fibres);
Nodular Kaposi's sarcoma (spindle cells, slit like spaces);
Pyogenic granuloma has a
diagnostic, lobular arrangement of capillaries that clearly distinguishes
it, histologically, from granulation tissue.
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