|Year : 2020 | Volume
| Issue : 2 | Page : 113-115
Segmental neurofibromatosis: A report of a rare case
Pratiksha Sonkusale, Sumit Kar, Pooja Bonde, Komal Ramteke
Department of Dermatology, Venereology and Leprosy, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, Maharashtra, India
|Date of Submission||27-Nov-2017|
|Date of Acceptance||24-Feb-2020|
|Date of Web Publication||15-Dec-2020|
Dr. Sumit Kar
Department of Dermatology, Venereology and Leprosy, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha - 442 102, Maharashtra
Source of Support: None, Conflict of Interest: None
Neurofibromatosis (NF) is a genetic disorder with an autosomal-dominant inheritance mainly affecting the growth of the cells of the neural tissues. Segmental NF (SNF), a rare variant of NF (NF type V), is characterized by café-au-lait macules and freckles or neurofibromas limited to one segment or one region of the body. A 26-year-old married female presented with asymptomatic café-au-lait macules and freckles involving the left cervical and thoracic region. The lesions did not cross the midline. Family history was not positive. There was no history of consanguineous marriage. There was no systemic involvement. We report this case as a rare entity of NF along with multidermatomal involvement.
Keywords: Café-au-lait macules, neurofibromatosis, neurofibromatosis type V, somatic mosaicism
|How to cite this article:|
Sonkusale P, Kar S, Bonde P, Ramteke K. Segmental neurofibromatosis: A report of a rare case. J Mahatma Gandhi Inst Med Sci 2020;25:113-5
| Introduction|| |
Neurofibromatosis (NF) is a genetic disorder of neural crest-derived cells that primarily affect growth of the neural tissues. It is broadly divided into three categories on the basis of their molecular aspects as NF-1 or von Recklinghausen's NF, NF-2 or bilateral acoustic neuroma, and finally, all other NF including alternate or atypical forms of the disease. Riccardi classification of NF (1982) classifies it into eight types. NF-1 or von Recklinghausen's NF was first described by von Recklinghausen in 1882 and is the most common form. Segmental NF (SNF type V) is a rare disorder characterized by café-au-lait macules and freckles or neurofibromas which are limited to one segment or one region of the body.
| Case Report|| |
A 26-year old woman noticed multiple hyperpigmented macules involving the left side of the forehead, chin, left side of the neck, postauricular area, left chest, left breast, left axilla, left forearm, and left postauricular region. These lesions had been present since the last four years. She gave the history of having a single hyperpigmented macule over the left forearm since childhood. The lesions were asymptomatic and painless. They did not cross the midline. Family history was not positive. There was no history of consanguineous marriage.
Physical examination showed seven discrete café-au-lait spots of sizes varying from 1- 5 cm on the left arm, sternum, chest, breast and postauricular area, [Figure 1], [Figure 2], [Figure 3] and freckles over the left side of the forehead, chin, left side of the neck, postauricular area, left chest, left breast, left axilla, left postauricular, and left scapular region. Axillary freckling was present on the left side [Figure 4]. Detailed neurological examination was normal. There was no cognitive and visual impairment. No ocular or skeletal deformity was present. No systemic involvement was present. Slit-lamp examination revealed no Lisch nodules on the iris. Magnetic resonance imaging of the spine was normal. Genetic counseling of the patient was done.
| Discussion|| |
SNF is a rare variant in which skin lesions are limited to a circumscribed body segment. Crowe et al. proposed the term sectorial NF for the localized form of NF. Miller and Sparkes modified the nomenclature to SNF. Riccardi classified SNF as NF type V. He described the clinical features of SNF as the presence of cafe-au-lait spots and/or neurofibromas in a single unilateral segment of the body, with no crossing of the median line, no family history, and no systemic involvement. Roth et al. have further subdivided the SNFs into four subtypes as true segmental, localized with deep involvement, hereditary, and bilateral.
SNF may be misdiagnosed as a birthmark or remain undiagnosed for long periods of time as the patients are often asymptomatic. It occurs in all age groups and has a mean age of onset of 28 years with a slight male preponderance (male-to-female ratio being 1.14–1). Its prevalence is estimated to be 0.0014% and 0.002%. SNF results from a postzygotic NF1 gene mutation located on the proximal long arm of chromosome 17 and represents somatic mosaicism. In many cases, the lesions follow the line of Blaschkos. They are usually unilateral and occupy single dermatome.
Ingordo et al. observed only one case of SNF out of 11 cases of NF in a group of 56183 young men between the age of 17 and 18 years representing a homogeneous population as per age, sex, race, and country of origin. The recent increase in the reported cases of SNF shows the rising interest of this variant and justifies the doubt about the rarity and underdiagnosis of SNF. Many times, the clinical picture of SNF can be underdiagnosed as they are asymptomatic. Clinically, patients may be divided into four groups as first with only pigmentary changes, second with only neurofibromas, third with both pigmentary changes and neurofibromas, and fourth with isolated plexiform neurofibromas.
Clinical disease (SNF) develops along the same time course as that of generalized NF with pigmentary changes, plexiform neurofibromas developing in childhood and neurofibromas developing in adulthood.
Some patients may develop complications such as learning difficulties, optic pathway gliomas, and pseudoarthrosis similar to those seen in NF1. Those patients manifesting with learning difficulties tended to have large areas of cutaneous involvement. Lisch nodules are rarely seen in segmental NF.
There is no specific strategy of management. Genetic counseling should be done, and the small risk of transmission to the offspring must be communicated. The evaluation of skin lesion and cognitive impairment is advised. Careful follow-up is required to monitor disease progression or to detect any systemic complications.
| Conclusion|| |
Our patient had unilateral cafe au lait macules and freckles localized over the left cervical and thoracic region with no positive family history suggestive of true segmental subtype of NF. If we go by other classification of SNF, our patients fall into the only pigmentary changes type. This case is presented as a case report due to its rarity.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]