Understanding multicentric haemangioendothelioma: diagnostic dilemmas and treatment strategies.

Epithelioid haemangioendothelioma (EH) is a rare malignant vascular tumour occurring mainly in the liver and lungs, with bones being a rare site and primarily seen in the adult population. This case presents a male patient in his 40s who presented to the outpatient department with a chief issue of a painless swelling over the inguinal region for 4 months, gradually increasing in size, along with a history of a gradually enlarging, painless mass on his left knee over the past 5 years. Despite occasional discomfort during physical activities, the mass exhibited no associated trauma, fever, weight loss or systemic symptoms. Physical examination revealed a firm mass on the left knee and a matted lymph nodal swelling in the left inguinal region. Subsequent imaging studies identified multiple soft tissue lesions, osseous involvement and pulmonary metastases, suggestive of multicentric haemangioendothelioma. The patient underwent surgical excision of the inguinal mass and fixation of a pathological fracture in the left femur. He is currently undergoing chemotherapy and is scheduled for regular follow-up appointments. This case underscores the importance of thorough diagnostic evaluation and multidisciplinary management in complex oncological conditions like multicentric haemangioendothelioma.