[Malignant pyoderma with cranial osteolysis].

BACKGROUND: Malignant pyoderma or pyoderma gangrenosum with cephalic involvement is a rare disease characterized by chronic aggressive local progression. We report a case of malignant pyoderma with cranial osteolysis. PATIENTS AND METHODS: A 42-year-old man had been presenting chronic ulcerative dermatosis involving the entire scalp since the age of sixteen. Clinical examination, histopathological analysis of the skin sample and negative aetiological tests suggested a diagnosis of cephalic pyoderma gangrenosum. Different treatments were ineffective. The patient was subsequently admitted with convulsions revealing cranial osteolysis. A cranial scan confirmed the osteolysis and histopathological analysis of the bone sample revealed non-specific suppurative osteitis. Treatment with corticosteroids and thalidomide was effective. Skin and bone grafting was proposed but was not carried out due to the chronic progression and absence of stable wound healing. DISCUSSION: Malignant pyoderma is a rare destructive, ulcerating dermatosis. It is characterized by a chronic course and resistance to treatment. Our case report is original in terms of the involvement of underlying cranial bone revealed by convulsions. This bone involvement makes treatment of the dermatosis more difficult.