Solitary fibrous tumors are very rare neoplasms that seldomly appear in extra-serosal soft tissues. In such cases, an accurate preoperative diagnosis is often difficult and challenging, especially in extrapleural ones. Traditionally, extrapleural solitary fibrous tumours have been regarded as indolent neoplasms similar to their intra-thoracic counterparts, although there has been some evidence that this subgroup could be a subset of more aggressive malignant tumours. For these reasons, surgical excision is mandatory and represents, to date, the best therapeutic option. In this article we report a case of a malignant solitary fibrous tumor of the chest wall in a 58-year-old man. Problems related to differential diagnosis and the possible pitfalls that can be encountered in the diagnostic process of such rare tumors are discussed.