This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vascular surgery, Subject name: Surgery
True about lymphangioma: 
Select and explain. 
A. It is a malignant tumour, B. It is a congenital sequestration of lymphatic channel, C. Laser excision is done, D. Sclerotherapy is common done
B: It is a congenital sequestration of lymphatic channel
Answer: B: It is a congenital sequestration of lymphatic channel 
Explanation: Lymphangioma: Lymphangiomas are the lymphatic analogue of the hemangiomas of blood vessels. Divided into two types: Simple or Capillary lymphangioma Cavernous lymphangioma or cystic hygroma. Clinical Features: Most of these benign tumours are present at bih, and 90% of them can be identified by the end of the first year of life Site of cavernous lymphangiomas: Mainly in neck and axilla (rarely in the retroperitoneum) Site of simple capillary lymphangiomas: Subcutaneously in the head and neck region and axilla. Represent isolated and sequestrated segments of the lymphatic system that retain the ability to produce lymph. As the volume of lymph inside the cystic tumour increases, they grow larger within the surrounding tissues. Treatment: Surgical excision, taking care to preserve all normal surrounding infiltrated structures. Ref: Sabiston 20th edition Pgno: 1855