Rhabdomyosarcoma (RMS) is the most common soft tissue malignancy in children and adolescents. The rarity of its occurrence in infant poses a great difficulty in terms of diagnosis and management. Here, we report an aggressive case of alveolar rhabdomyosarcoma in an infant who presented with neck swelling and neurological complications. The Magnetic Resonance Imaging (MRI) revealed a soft tissue swelling of the neck with intraspinal extension and spinal cord compression, raising the possibility of a neurogenic or malignant nerve sheath tumour. Histopathological examination revealed a primitive, small round cell tumour with no rhabdoid differentiation. The clinical presentation, neurological symptoms, tumor location and the histopathologic features were highly suggestive of neuroblastoma. However, the tumour cells were positive for desmin with focal and weak nuclear positivity for myogenin and MyoD1; immunoexpressions which were in favour of rhabdomyosarcoma. Fluorescent in situ hybridization (FISH) confirmed the presence of a translocation t(2;13)(q35;q14), supporting the diagnosis of alveolar rhabdomyosarcoma. Despite chemotherapy, patient succumbed to death after two months due to septic shock. Rhabdomyosarcoma is highly aggressive mesenchymal neoplasm which may present with diagnostic difficulty. This case highlights the importance of molecular studies in making an accurate diagnosis so that appropriate chemotherapy may be instituted.
Solitary fibrous tumour (SFT) is a fibrotic neoplasm, also previously designated as hemangiopericytoma. STAT6 is a protein for signal tranducers and activators of transcription (STAT) family which is involved in immune function and early cell growth. Oncogenic alteration of STAT6 plays an important role for specific driver for tumour genesis of solitary fibrous tumour via NAB2-STAT6 fusion gene. The aim of the study was to compare and evaluate STAT6 expression between SFT and other soft tissue histological mimics. We evaluated a total of 30 cases material formalin fixed paraffin embedded tissue block previously diagnosed SFT cases (n=14) and soft tissue tumours mimic cases (n=16) over period of 15 years. Fourteen SFT cases (100%) showed nuclear expression of STAT6, which was diffuse and intense. All other tumour types were negative for STAT6, except for one case of dedifferentiated liposarcoma, one gastrointestinal stromal tumour and one spindle cell lipoma, which showed weak non-specific cytoplasmic staining. Nuclear STAT6 expression is useful and reliable as adjunctive marker for solitary fibrous tumour when the diagnosis is inconclusive by conventional methods.
A 47-year-old lady, presented with progressive proptosis of left eye with deterioration of vision. She had a history of left solitary fibrous tumour and had undergone left frontal craniotomy and orbitotomy in 2004. Surveillance Magnetic resonance imaging (MRI) six years later showed tumour recurrence with intracranial extension. However, she did not follow-up and only presented again 3 years, later. Tumour resection and left exenteration was performed. Histology showed ‘patternless’ pattern of neoplastic cells, and CD34 staining was diffusely positive. Diagnosis of recurrent solitary fibrous tumour with intracranial extension was made.