A haematoma, or hematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise.
Chronic expanding haematoma of soft tissue is a rare entity. It is characterized by its persistence and by its increasing size for more than a month after the initial haemorrhage. The diagnosis of this uncommon entity is often difficult, it being easily mistaken for one of the relatively more frequent malignant neoplasms (cancer).
Mr X presented to me with a large lump over his right shin. This lump has been with him for over 10 years but he noticed that it was gradually becoming bigger. It first started as a small lump after he was kicked in the shin during a game of football.
The lump did not cause him any pain or discomfort but it was obvious and appeared alarming to his friends and relatives.
Examination showed a large firm mass over the front of his right shin.
X-rays showed a soft tissue lump or tumour.
Fearing this could be a benign soft tissue lump that has turned cancerous, an MRI scan was promptly done.
The features were worrisome and suggestive of a cancer of the soft tissue or what we called a soft tissue sarcoma.
Fearing the worst, surgical excision of the tumour was advised.
The lump was treated as a cancerous lump and excised as such.
This is the tumour after it was removed from the leg.
The tumour was excised enbloc with a cuff of normal tissues.
The excised lump was sent for histology. It turned out to be a chronic organizing haematoma!
Most hematomas subside without causing any serious clinical problems. However, some persist for long periods and appear clinically as slowly expanding lesions in soft tissues simulating neoplastic growth; these are called chronic expanding hematomas.
The precise mechanism responsible for chronic expanding hematomas remains unclear. Bradshaw et al. speculated that the initial trauma results in displacement of skin and subcutaneous fatty tissue away from more deeply located, fixed fascia and underlying muscle, with the consequent formation of blood-filled cysts surrounded by dense fibrous tissue. The lesion’s self-perpetuating, expanding nature appears to be due to the irritant effects of blood and its breakdown products leading to repeated exudation or bleeding from capillaries in the granulation tissue of the cyst wall.
It seems that complete surgical excision, including the pseudocapsule, is the best treatment for chronic expanding hematoma, because aspiration of the fluid or incomplete excision could lead either to an unconfirmed diagnosis or recurrence.