A rare case of plexiform neurofibroma.

Plexiform neurofibroma is a rare benign peripheral nerve sheath tumor that occurs almost exclusively in patients with neurofibromatosis type I (NF1). This report presents a 10-year-old patient with multiple enlarging masses on the left and posterior neck for 4 years, accompanied by pain and restricted neck movement. Radiographic evaluation revealed a soft tissue mass without bony abnormalities, while Magnetic Resonance Imaging (MRI) demonstrated multiple confluent, ill-defined, infiltrative lesions involving bilateral cervical regions and extending into the anterior mediastinum. The lesions showed hypointense signals on T1-weighted and hyperintense target sign appearances on T2-weighted images, with encasement of neurovascular structures and spinal cord compression. Histopathological findings confirmed the diagnosis of plexiform neurofibroma without evidence of malignancy. This case emphasizes the diagnostic value of MRI in delineating lesion extent and neurogenic origin, as well as the importance of histopathology in confirming the benign nature of the tumor and excluding malignant transformation.