Primary localised pleural neurofibroma: expanding the spectrum of spindle cell tumours of the pleura

Aims Primary localised pleural neoplasms are a rare group of thoracic tumours, with solitary fibrous tumour representing the most frequently encountered entity. Two cases of localised pleural neurofibromas involving the pleura are described. Methods and results The patients were both female: 78 and 29 years of age. In the former a pleural-based lesion was identified on a chest radiograph after she presented with shoulder pain. The second patient was known to have neurofibromatosis type I, and the pleural lesion was found incidentally during excision of a metastatic malignant peripheral nerve sheath tumour of the lung. Both tumours were localised and composed histologically of bland neoplastic spindle cells embedded in a loose collagenous matrix. There was variable immunoreactivity for S100 and CD34, while ultrastructure examination in the two cases showed a mixture of nerve sheath cell types. Conclusion To the best of the authors' knowledge, localised neurofibromas have not been previously reported within the pleura. The presence of a bland spindle cell pleural neoplasm immunoreactive for CD34 may potentially be mistaken for a solitary fibrous tumour. While distinction is usually achieved on close attention to the histological features, staining with S100 protein, especially in small biopsies, should be considered to exclude a neurofibroma.