[Chronic expanding hematoma of the soleus: a case report]

Trauma-induced hematomas of the limbs usually resorb without sequelae. In certain circumstances which are not fully understood, the hematoma may expand progressively, eventually leading to the development of a tumor-like mass in the soft tissues. We report the case of a chronic expanding hematoma observed in the right soleus muscle of a 75-year-old man. The mass grew +9 cm compared with the other side over a period of two to three years with no notion of recent trauma. Surgical biopsy disclosed a thick capsule containing "chocolate pus". Pathology and cytology examination led to the diagnosis of pseudo-tumor calcinosis subsequent to a hematoma which the patient had developed 34 years earlier when as a mountain guide he had experienced a tear of the soleus muscle. Local care required complete resection of the soleus muscle. The patient was able to resume activities without pain. Well described in the literature, encapsulated hematoma of the limbs is not well known in France. This case illustrated the potentially long latency period (34 years in our patient). Pathologically similar to tumor calcinosis, chronic expanding hematoma should be entertained as a possible diagnosis in a patient with a longstanding mass and a history of past trauma. The differential diagnosis with sarcoma is established by magnetic resonance imaging which reveals a peripheral low intensity signal on T1 and T2 sequences.