THE NERVE THAT NEVER RESTED: PLEXIFORM NEUROFIBROMA PRESENTING AS MASSIVE SOFT TISSUE SWELLING IN AN 82-YEAR-OLD: A LINICOPATHOLOGICAL STUDY

Abstract

Background: Plexiform neurofibroma is a rare benign peripheral nerve sheath tumour that is strongly associated with Neurofibromatosis Type 1 (NF1). Although most lesions present during childhood or early adulthood, giant plexiform neurofibromas occurring in elderly individuals without an established diagnosis of NF1 are exceptionally uncommon and frequently mimic malignant soft tissue tumours, posing significant diagnostic and therapeutic challenges. Case Presentation: An 82-year-old female presented with progressively enlarging swellings over the right thigh and right leg for five years, associated with rapid enlargement and pain during the preceding few months. Magnetic resonance imaging demonstrated a well-defined multilobulated exophytic subcutaneous lesion measuring 140 × 130 × 110 mm in the medial aspect of the right thigh and a large ill-defined intramuscular lesion measuring 245 × 122 × 85 mm involving the anterior compartment of the right leg with trans-fascial extension. Multiple cutaneous and subcutaneous nodules were identified throughout the thigh, raising suspicion of a plexiform neurofibroma with malignant peripheral nerve sheath tumour as an important differential diagnosis. Histopathological examination of the biopsy and excised specimens demonstrated spindle-shaped cells with elongated wavy nuclei embedded within abundant myxoid and collagenous stroma without significant atypia, increased mitotic activity, or tumour necrosis. Complete surgical excision was performed, and the final diagnosis was diffuse (plexiform) neurofibroma with tumour-free surgical margins. Immunohistochemistry was recommended for definitive confirmation. Conclusion: This case highlights the rare presentation of a giant diffuse plexiform neurofibroma in an elderly patient without documented NF1. Despite its enormous size and aggressive radiological appearance, histopathological evaluation confirmed a benign lesion. Accurate diagnosis requires careful correlation of clinical findings, imaging, histopathology, and ancillary investigations. Complete surgical excision remains the treatment of choice for resectable lesions, while long term clinical and radiological surveillance is essential because of the recognised risk of recurrence and malignant transformation.Background: Plexiform neurofibroma is a rare benign peripheral nerve sheath tumour that is strongly associated with Neurofibromatosis Type 1 (NF1). Although most lesions present during childhood or early adulthood, giant plexiform neurofibromas occurring in elderly individuals without an established diagnosis of NF1 are exceptionally uncommon and frequently mimic malignant soft tissue tumours, posing significant diagnostic and therapeutic challenges. Case Presentation: An 82-year-old female presented with progressively enlarging swellings over the right thigh and right leg for five years, associated with rapid enlargement and pain during the preceding few months. Magnetic resonance imaging demonstrated a well-defined multilobulated exophytic subcutaneous lesion measuring 140 × 130 × 110 mm in the medial aspect of the right thigh and a large ill-defined intramuscular lesion measuring 245 × 122 × 85 mm involving the anterior compartment of the right leg with trans-fascial extension. Multiple cutaneous and subcutaneous nodules were identified throughout the thigh, raising suspicion of a plexiform neurofibroma with malignant peripheral nerve sheath tumour as an important differential diagnosis. Histopathological examination of the biopsy and excised specimens demonstrated spindle-shaped cells with elongated wavy nuclei embedded within abundant myxoid and collagenous stroma without significant atypia, increased mitotic activity, or tumour necrosis. Complete surgical excision was performed, and the final diagnosis was diffuse (plexiform) neurofibroma with tumour-free surgical margins. Immunohistochemistry was recommended for definitive confirmation. Conclusion: This case highlights the rare presentation of a giant diffuse plexiform neurofibroma in an elderly patient without documented NF1. Despite its enormous size and aggressive radiological appearance, histopathological evaluation confirmed a benign lesion. Accurate diagnosis requires careful correlation of clinical findings, imaging, histopathology, and ancillary investigations. Complete surgical excision remains the treatment of choice for resectable lesions, while long term clinical and radiological surveillance is essential because of the recognised risk of recurrence and malignant transformation.