Primary pleuropulmonary synovial sarcoma with brain metastases in a paediatric patient: an unusual presentation.

Primary lung neoplasms are rare in children. The most common primary lung malignancies in children are pleuropulmonary blastoma and carcinoid tumour. Synovial sarcoma (SS) accounts for approximately 1% of all childhood malignancies. In absolute terms, the SS of the lungs and pleura are extremely rare and pose a diagnostic difficulty. Soft tissue sarcomas usually have a high potential for metastases, however, metastasis to the brain is rare, even in widely disseminated disease, and it has been described only in 3 case reports previously. Primary pleuropulmonary SS with brain metastases is even rarer. Here we present a case of an 11-year-old boy who presented with respiratory complaints, viz. fever and cough for 20 days. Initial impression was lung abscess, however, on histopathological, immunohistochemical and molecular study, the disorder was diagnosed as synovial sarcoma. After a week from the first consult, the child developed neurological symptoms, viz., an episode of convulsion and gradually worsening power of the lower limb. Computed tomography scan and Magnetic Resonance Spectroscopy was suggestive of brain metastases. Given the rarity of primary lung neoplasms in children, clinical detection remains a challenge. Delayed diagnoses are common as respiratory symptoms may be attributed to inflammatory or infective processes. Primary pleuropulmonary synovial sarcoma is a rare tumour and it is not known to commonly metastasise to the brain. Though rare, primary pleuropulmonary SS should be considered an important differential among peadiatric primary lung neoplasms due to its potential for curability if detected early, and more aggressive metastatic pattern, e.g. brain metastases making early detection imperative.