Table 3.

Comparison of whole-body MRI findings in NF1 patients with MPNSTs younger or older than the median age and matched control NF1 patients without MPNSTs

	Age <30 Years		Age >30 Years
Group	NF1 with MPNSTs	NF1 without MPNSTs	NF1 with MPNSTs	NF1 without MPNSTs
Total number	6	11	7	15
Median number of externally visible plexiform neurofibromas (range)	0.5 (0–3)	1 (0–3)	1 (0–10)	1 (0–5)
Median number of subcutaneous neurofibromas (range)	112.5* (0–2000)	2* (0–30)	40 (10–300)	25 (0–1000)
Median number of cutaneous neurofibromas (range)	0 (0–400)	4 (0–300)	300 (0–5000)	30 (0–1000)
Number of patients with internal neurofibromas on MRI (%)	6‡ (100)	3‡ (27)	3 (43)	10 (67)
Median number of internal neurofibromas >3 cm (range)	1† (1–4)	0† (0–3)	0 (0–3)	1 (0–9)
Median internal neurofibroma volume, ml (range)	460** (8–2252)	0** (0–5588)	0 (0–825)	115 (0–7030)
Number with spinal neurofibromas (%)	4 (67)	6 (54)	5 (71)	6 (40)

Abbreviations: NF1, neurofibromatosis 1; MPNSTs, malignant peripheral nerve sheath tumors.

^*p = 0.048 by Mann-Whitney U test;

^†p = 0.027 by Mann-Whitney U test;

^‡p = 0.009 by Fisher’s exact test;

^**p = 0.037 by Mann-Whitney U test.