The patient was diagnosed with neurofibromatosis type 1 (NF1) with multiple cutaneous neurofibromas. Plexiform neurofibromatosis is pathognomic of NF1 and mediastinal location mimics lymphadenopathy. Significant risk of malignant transformation is well known in plexiform neurofibromatosis.

Histology report

Microscopy: Sections reveal fragments of tumor tissue with large areas of necrosis. There are intervening spindle cell proliferation composed of fascicular arrangement of pump and spindly cells with moderate nuclear atypia. Mitotic figures are seen. Background shows fibro myxoid stroma. Surrounding adipose tissue with possible lymphoid follicles are also seen. In addition there is well defined area of benign looking spindly cells with wavy nuclei in background of fibromyxoid stroma, favoring neurofibroma.

Contributed by Dr Sumudu Palihawadane and Dr Chamali Athauda