Lisch nodule

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Swathi Venkatesan, M.B.B.S.[2]

Synonyms and keywords: Sakurai-lisch nodule

Natural History, Complications and Prognosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3] Swathi Venkatesan, M.B.B.S.[4]

• The prognosis is excellent for eyes that contain iris Lisch nodules, unless associated with other ocular lesions including optic nerve gliomas and epiretinal membranes.
• NF1 and NF2 vary based on location of chromosome mutation, tumor type and location, non-tumor manifestations and management techniques; however, clinical presentations of both subtypes may overlap, making diagnosis difficult
• Both NF1 and NF2 are acquired through an inherited autosomal dominant transmission or sporadic mutation, with presentation of NF1 more common than NF2.
• Therefore, members of the same family with NF may have different disease presentations from each other, as they do not always carry the same gene mutations.
• Lisch nodules rarely cause ocular complications and patients are typically asymptomatic
• NF patients may also present with plexiform neurofibroma, retinal tumors and optic nerve pathway gliomas as optical lesions

Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [5] Swathi Venkatesan, M.B.B.S.[6]

History & Symptoms

Diagnostic Criteria for neurofibromatosis 1

(NIH consensus development conference 1988)

• 6 or more café au lait macules (>0.5 cm in children or >1.5 cm in adults)
• 2 or more cutaneous/subcutaneous neurofibromas or one plexiform neurofibroma
• Axillary or groin freckling
• Optic pathway glioma
• 2 or more Lisch nodules (iris hamartomas seen on slit lamp examination)
• Bony dysplasia (sphenoid wing dysplasia, bowing of long bone ± pseudarthrosis)
• First degree relative with NF1

The diagnosis is based on clinical assessment and two or more of the features are required.

Lisch Nodule Physical Examination Findings

• Lisch nodules occur in 90% of adults with neurofibromatosis 1.
• Eye-findings include orange-brown colored specks.
• They are usually elevated and tan in appearance.
• These are benign hamartomas that can be seen without magnification.
• Also known as melanocytic hamartomas of the iris, often associated with neurofibromatosis (NF) I
• Other associated ophthalmologic findings are optic gliomas
  • Optic gliomas can alter color vision and can produce progressive sight loss

Lisch nodule Diagnostic Studies==

• On slit-lamp examination, they have a smooth, dome-shaped appearance and are usually light brown, although some can be very pale.
• Slit lamp examination can differentiate them from nevi on the iris by demonstrating elevated lesion instead of flat ones.
• Lisch nodules develop during childhood, after the appearance of café-au-lait spots but before peripheral neurofibromas
• This is useful in confirming the diagnosis of NF1 in children with no family history and only multiple café-au-lait spots

Treatment

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [7] Swathi Venkatesan, M.B.B.S.[8]

Medical Therapy

• There is no treatment for the underlying disease nor any necessity to treat these small benign lesions which do not interfere with visual function, but lifelong monitoring is necessary because of the widespread manifestations and serious threat of complications such as visual impairment, renal hypertension and ischemia of major organs.

Case Studies

Case #1