Pathology of Pyogenic Granuloma -(Lobular Capillary Hemangioma)

Dr Sampurna Roy MD               2022

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.

[Lobular capillary hemangiomas - a group of vascular lesions characterized by capillary sized vessels arranged in lobules. ]

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. 

Clinical presentation:

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. 

Microscopic features:

   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.  

Image1 ; Image2 ;  Image3 ;   Image4

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.

Differential diagnosis:

Well differentiated angiosarcoma (poor circumsription, cellular pleomorphism  and dissection of collagen fibres); 

Nodular Kaposi's sarcoma (spindle cells, slit like spaces);

Bacillary angiomatosis ;   Verruga peruana ;

Pyogenic granuloma has a diagnostic, lobular arrangement of capillaries that clearly distinguishes it, histologically, from granulation tissue.
 

Capillary hemangioma of the central nervous system: a comparative study with lobular capillary hemangioma of the skin.

Extramedullary hematopoiesis in a pyogenic granuloma: a case report and review.

Pyogenic granuloma: an unrecognized cause of gastrointestinal bleeding.

Cutaneous lobular capillary hemangioma induced by pregnancy.

Pathogenetic roles of angiogenic factors in pyogenic granulomas in pregnancy are modulated by female sex hormones.

Human herpesvirus 8 (HHV-8) detected in two patients with Kaposi's sarcoma-like pyogenic granuloma.

Pathological case of the month: diagnosis and discussion; pyogenic granuloma of the tongue.

Lobular capillary haemangioma of the nasal cavity: observation of three specific cases.

Pyogenic granuloma: pyogenic again? Association between pyogenic granuloma and Bartonella.