Introduction: Defence injuries are the results of immediate and instinctive reaction of the victims in order to protect themselves during an assault. Presence of such injuries indicates that the victim was conscious and could comprehend the attack and provide resistance. They also help in identifying the weapon. The objectives of our study were to differentiate the patterns and the distributions of defence injuries. Methodology: This study was carried out on selected patients admitted to the hospital following assaults and deaths following injuries who had defence injuries during the period of March 2015 to January 2016 at Teaching Hospital, Karapitiya, General Hospital, Matara and Base Hospital Hambanthota which are the major hospitals in the Southern Province of Sri Lanka. Results: We analyzed 213 cases with defence injuries. Out of them 75% were males. The commonest age group who had defence injuries were between 31-40 years. Blunt force defence injuries were present in 154 cases and sharp force was present in 74 cases. The commonest type of defence injury was contusion followed by abrasion. The commonest anatomical area involved was the forearm followed by the hand. Both left and right upper limbs involved equally in defensing although the majority (94%) was right dominant. More than one injury was present in 45% of cases and 18% had underlying injuries. In 17.8% cases alcohol had been consumed prior to the incident. Head and face was the most frequently protected body part (57%) followed by the chest (14%). Ninety eight percent of victims did not have pre-existing disabilities and 81% of them the assailant was known. Conclusions: Back of forearm is the commonly used site for defence and there is no clear correlation with the handedness and defence wounds.

Introduction Mediastinal tumours are often seen in patients aged 30-50 years. Most of them are neurogenic tumours and thymomas. Others include lymphomas, phaeochromocytomas, melanomas, germ cell tumours and thyroid and parathyroid lesions. Although primary cardiac tumours are rare, metastasis in the heart is commoner than primary cardiac tumours. Case report A 41 year old woman was admitted to the Teaching Hospital, Karapitiya with a recent onset progressive dyspnoea. She was found to have a rapidly filling pericardial effusion. She died on the third day of admission. A whitish mass infiltrating the full thickness of the right atrial myocardium was found at the autopsy. A similar tumour was present in the anterior mediastinum measuring 7x3cm. There was no direct connection between the two tumours. H&E stained sections revealed a similar microscopic appearance in both mediastinal and cardiac masses. The differential diagnosis included lymphoma, melanoma, carcinoma and germ cell tumors. Immunohistochemical staining for LCA, pan cytokeratin, S100 and PLAP were done and only S100 was positive. Conclusion Negative staining for LCA, pan cytokeratin and PLAP excluded the possibility of lymphoma, carcinoma and germ cell tumours. Positive staining for S100 confirmed the diagnosis of melanoma. This was diagnosed as a rare case of primary mediastinal malignant melanoma with a right atrial metastasis causing pericardial effusion.

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