A child with multiple café-au-lait macules (8 in number, >5 mm each), axillary freckling, and 2 Lisch nodules is diagnosed with neurofibromatosis type 1. The minimum number of café-au-lait spots required as a diagnostic criterion (without other features) in a prepubertal child is:

• A 3 spots of any size
• B 5 spots measuring >5 mm in greatest diameter
• C 10 spots measuring >5 mm
• D 6 spots measuring >5 mm in prepubertal children (>15 mm in post-pubertal) ✓

Explanation

NF1 requires 2 or more of 7 diagnostic criteria. One criterion is ≥6 café-au-lait macules measuring >5 mm in prepubertal individuals (or >15 mm in postpubertal individuals). Other criteria include neurofibromas, axillary/inguinal freckling, optic glioma, Lisch nodules (≥2), bony dysplasias, and first-degree relative with NF1. Lisch nodules are pathognomonic iris hamartomas visible on slit-lamp examination.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.