Targetoid hemosiderotic hemangioma

Targetoid Hemosiderotic Hemangioma (THH), also known as Hobnail Hemangioma, is a benign vascular lesion of the skin. It is a rare condition, often misdiagnosed due to its clinical and histological similarities with other skin conditions.

Clinical Presentation[edit | edit source]

THH typically presents as a solitary, red to purple papule or nodule. It is often characterized by a central dark area surrounded by a pale ring, giving it a "targetoid" appearance. The lesions are usually less than 1 cm in diameter and can occur anywhere on the body, but are most commonly found on the limbs. Patients may report a history of rapid growth followed by stability.

Histopathology[edit | edit source]

Histologically, THH is characterized by a biphasic pattern with dilated, thin-walled vessels in the superficial dermis and smaller, thick-walled vessels in the deeper dermis. The vessels are lined by endothelial cells with a characteristic "hobnail" appearance. There is often a significant amount of hemosiderin deposition, which gives the lesion its characteristic color.

Diagnosis[edit | edit source]

Diagnosis of THH is primarily based on histopathological examination. Due to its clinical resemblance to other conditions such as Kaposi's sarcoma, melanoma, and pyogenic granuloma, a biopsy is often necessary to confirm the diagnosis.

Treatment[edit | edit source]

Treatment of THH is usually not necessary as the lesions are benign and often self-resolving. However, if the lesion is causing discomfort or cosmetic concern, it can be removed by surgical excision or laser therapy.