Lisch nodule

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Swathi Venkatesan, M.B.B.S.[2]

Synonyms and Keywords: Sakurai-lisch nodule

Overview

Lisch nodules are well defined melanocytic hamartomas of the iris. Lisch nodules generally appear as dome-shaped gelatinous masses. Lisch nodules masses are more commonly develop on the surface of the iris, also known as iris hamartomas. Lisch nodules are gold-tan to brown in color, they may grow up to 2 mm in diameter and can be of different sizes on the same iris. Lisch nodules arise from mast cells, pigmented cells and fibroblast-like cells. The presence of Lisch nodules is the most common clinical sign of Neurofibromatosis 1; ninety-three percent of cases are bilaterally affected and an average of 25 nodules can be counted on each iris. Once iris hamartomas have developed, they remain stable throughout life. In 80% of eyes, Lisch nodules may be found in the inferior quadrants of the iris and this may be related to greater sun exposure, one of the postulated factors in the development of these benign tumefactions.

Historical Perspective

Lisch nodule classification

  • There is no established system for the classification of Lisch nodules.

Pathophysiology

Lisch nodule causes

Lisch nodule differential diagnosis

Epidemiology and Demographics

Incidence

Prevalence

  • The prevalence of Lisch nodules is approximately 1 in 3500 individuals worldwide.

Age

  • Lisch nodules are predominantly visible in children usually after the age of six years.
  • Lisch Nodule incidence in NF1 increases with age and their prevalence raises by about 10% per year of life, up to age 9.
  • Lisch nodules are found in 93% of adults with NF-1 but have not been described in NF-2.
  • Lisch Nodules may be found in a very limited number of individuals without NF.
  • The de novo mutations occur primarily in paternally derived chromosomes, and the likelihood of de novo NF1 increases with advanced paternal age.

Risk Factors

Screening

  • Lisch Nodules are not regularly screened, they’re usually detected when other signs and symptoms of neurofibromatosis appear.[10]
  • However, Lisch nodules are seen in 95% of children with NF1 by age 20

Natural History, Complications and Prognosis

Natural History

Complications

Prognosis

Diagnosis

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.

Physical Examination

  • 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

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.

References

  1. Antônio JR, Goloni-Bertollo EM, Trídico LA (2013). "Neurofibromatosis: chronological history and current issues". An Bras Dermatol. 88 (3): 329–43. doi:10.1590/abd1806-4841.20132125. PMC 3754363. PMID 23793209.
  2. Hosoi, Kiyoshi (1931). "MULTIPLE NEUROFIBROMATOSIS (von RECKLINGHAUSEN'S DISEASE)". Archives of Surgery. 22 (2): 258. doi:10.1001/archsurg.1931.01160020081004. ISSN 0272-5533.
  3. Gabhane SK, Kotwal MN, Bobhate SK (2010). "Segmental neurofibromatosis: a report of 3 cases". Indian J Dermatol. 55 (1): 105–8. doi:10.4103/0019-5154.60366. PMC 2856359. PMID 20418991.
  4. Boley S, Sloan JL, Pemov A, Stewart DR (2009). "A quantitative assessment of the burden and distribution of Lisch nodules in adults with neurofibromatosis type 1". Invest Ophthalmol Vis Sci. 50 (11): 5035–43. doi:10.1167/iovs.09-3650. PMC 2883270. PMID 19516012.
  5. Boyd KP, Korf BR, Theos A (2009). "Neurofibromatosis type 1". J Am Acad Dermatol. 61 (1): 1–14, quiz 15-6. doi:10.1016/j.jaad.2008.12.051. PMC 2716546. PMID 19539839.
  6. Lubs, Marie-Louise E.; Bauer, Mislen S.; Formas, Maria E.; Djokic, Borivoje (1991). "Lisch Nodules in Neurofibromatosis Type 1". New England Journal of Medicine. 324 (18): 1264–1266. doi:10.1056/NEJM199105023241807. ISSN 0028-4793.
  7. Radius RL, Herschler J (1980). "Histopathology in the iris-nevus (Cogan-Reese) syndrome". Am J Ophthalmol. 89 (6): 780–6. doi:10.1016/0002-9394(80)90165-8. PMID 6992584.
  8. Makley TA, Kapetansky FM (1988). "Iris nevus syndrome". Ann Ophthalmol. 20 (8): 311–5. PMID 3190109.
  9. Lubs, Marie-Louise E.; Bauer, Mislen S.; Formas, Maria E.; Djokic, Borivoje (1991). "Lisch Nodules in Neurofibromatosis Type 1". New England Journal of Medicine. 324 (18): 1264–1266. doi:10.1056/NEJM199105023241807. ISSN 0028-4793.
  10. Lubs, Marie-Louise E.; Bauer, Mislen S.; Formas, Maria E.; Djokic, Borivoje (1991). "Lisch Nodules in Neurofibromatosis Type 1". New England Journal of Medicine. 324 (18): 1264–1266. doi:10.1056/NEJM199105023241807. ISSN 0028-4793.

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