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

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

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

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

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.

Epidemiology

THH is a rare condition with no known predilection for age, sex, or race. It has been reported in patients of all ages, from infants to the elderly.

See Also

• Hemangioma
• Vascular lesion
• Dermatology