Retroperitoneal Neurofibroma and a Malignant Peripheral Nerve Sheath Tumor with Neurofibromatosis Type 1: A Report of Two Cases

Intranodal Neurofibroma: A Case Report and Literature Review

“…In total, there were 5 reported cases, 2 of which were plexiform neurofibroma, 1,2 one a localized neurofibroma that gave rise to an adjacent malignant peripheral nerve sheath tumor (MPNST), 3 and 2 with limited descriptions. 4,5…”

“…11 Neurofibroma has been described to occur nearly anywhere in the body throughout the peripheral nervous system including within the cutaneous, subcutaneous, and deep tissues of the head, neck, extremities, trunk and abdominal wall, in the spine, mediastinum, liver, mesentery, and retroperitoneum, and any segment of the gastrointestinal tract. 3,[12][13][14][15][16][17][18][19][20] Histologically, neurofibroma is a somewhat demarcated but unencapsulated nodule containing clusters of elongated cells with S-shaped or wavy darkly staining nuclei, admixed with strands of collagen said to appear as shredded carrots, in a background of pale pink mucinous or myxoid stroma dotted with numerous mast cells. 11,21,22 Neurofibroma shows S100positive Schwann cells, lattice-like CD34-positive fibroblasts, factor XIIIa-positive fibroblast-like cells, and neurofilaments.…”

“…11 Neurofibroma has been described to occur nearly anywhere in the body throughout the peripheral nervous system including within the cutaneous, subcutaneous, and deep tissues of the head, neck, extremities, trunk and abdominal wall, in the spine, mediastinum, liver, mesentery, and retroperitoneum, and any segment of the gastrointestinal tract. 3,12–20…”

“…Histological examination of the outside area showed a neurofibroma, whereas the inner lesion had the features of an MPNST. The final diagnosis was “MPNST arising from a neurofibroma.” 3 (2) A 6-year-old man with >6 cutaneous café au lait spots presented with painful parotid swelling, which upon surgical excision and pathologic examination showed a 6- × 4.2- × 3-cm nonencapsulated nodular mass with histologic features of plexiform neurofibroma including scattered mast cells with worm-like bundles of nerve fibers in a background of myxoid degeneration. The lesion was also found to involve an intraparotid lymph node penetrating through the hilum.…”

Neurofibroma in the retroperitoneum associated with neurofibromatosis type 1

“…MPNSTs can arise from any neurofibroma, regardless of location, and patients with NF1 may have MPNSTs, especially in the retroperitoneum. 1 The prognosis of MPNSTs may be poor because of their rapid growth and the possibility of distant metastasis. 2 Furthermore, retroperitoneal tumours rarely present with specific symptoms, and delayed diagnosis is one of the factors for poor prognosis.…”