|Year : 2016 | Volume
| Issue : 3 | Page : 238-240
Psoriasis vulgaris occurring in a known case of neurofibromatosis type I: A rare association
Konakanchi Venkata Chalam, Gummalla Ajay Kumar, Padmasri S Yandapalli, Anila P Sunandini
Department of Dermatology Venereology and Leprosy, Andhra Medical College, Visakhapatnam, Andhra Pradesh, India
|Date of Web Publication||10-Oct-2016|
Padmasri S Yandapalli
Department of Dermatology Venereology and Leprosy, Andhra Medical College, Visakhapatnam, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Neurofibromatosis type 1 (NF-1) is an autosomal dominantly inherited neurocutaneous disorder due to mutations in the neurofibromin (NF) gene that encodes protein NF. NF regulates signal transduction by inactivating RAS proteins. Mutations in the NF-1 gene increases RAS activity causing increased transduction of many growth factors and kinase pathways leading to increased mitosis and occurrence of neoplasms and proliferative conditions such as psoriasis. Psoriasis is a chronic, inflammatory proliferative condition of the skin in which both genetic and environmental factors have a vital role. The underlying pathogenesis is epidermal proliferation, vascular changes, and inflammatory changes mediated by multiple growth factors of which in particular are epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, tumor necrosis factor (TNF)-alpha etc. We report a rare association of NF-1 with psoriasis occurring by chance or due to decreased NF protein.
Keywords: Neurofibromatosis type 1 (NF-1), neurofibromin (NF) gene, psoriasis
|How to cite this article:|
Chalam KV, Kumar GA, Yandapalli PS, Sunandini AP. Psoriasis vulgaris occurring in a known case of neurofibromatosis type I: A rare association. J NTR Univ Health Sci 2016;5:238-40
|How to cite this URL:|
Chalam KV, Kumar GA, Yandapalli PS, Sunandini AP. Psoriasis vulgaris occurring in a known case of neurofibromatosis type I: A rare association. J NTR Univ Health Sci [serial online] 2016 [cited 2019 Jul 24];5:238-40. Available from: http://www.jdrntruhs.org/text.asp?2016/5/3/238/191838
| Introduction|| |
Neurofibromatosis type 1 (NF-1) is an autosomal dominantly inherited disorder due to mutations in the NF gene. Mutations in the NF-1 gene increases RAS activity, causing increased transduction of many growth factors, mitosis and occurrence of neoplasms, and proliferative conditions such as psoriasis. Psoriasis is an inflammatory proliferative condition of the skin mediated by many growth factors like epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, tumor necrosis factor (TNF)-alpha etc. Though psoriasis is not a common association with NF, however, underlying genetic defect in NF may perpetuate the occurrence of psoriasis. There are no statistically significant case reports of this rare occurrence. We report a rare association of NF-1 with psoriasis occurring as by chance or due to decreased NF protein.
| Case Report|| |
A 28-year-old unmarried female who was a known case of NF-1 developed psoriasis admitted in the department of dermatology for treatment. She noticed multiple nodules and café-au-lait macules when she was 9-year-old and the lesions gradually involved the entire body. She developed psoriatic lesions at 10 years of age. There were remissions and multiple recurrences of psoriatic lesions for which she took topical steroids. There was no family history suggestive of psoriasis or NF.
Dermatological examination revealed multiple neurofibromas, café-au-lait macules (>15 mm diameter and >10 in number), freckles all over the body with crow's-feet-sign positive [Figure 1]. Slit-lamp examination showed multiple lisch nodules. There were multiple psoriatic plaques that are mainly distributed over the extensor aspects and lower back [Figure 2], thighs lower legs, and some lesions were present over the neurofibromas [Figure 3].
|Figure 2: Psoriatic plaques over lower back, extensors of upperlimbs along with presence of neurofibromas|
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Histopathology from lesion of cutaneous nodule with overlying psoriatic plaque [Figure 4] and [Figure 5], epidermis there was hyperkeratosis, hyperplasia, and parakeratosis, club-shaped rete ridges, suprapapillary thinning of epidermis, dilated tortuous papillary blood vessels, surrounded by mixed inflammatory cells with extravasation of erythrocytes which are characteristic of psoriasis [Figure 4]. Dermis and subcutaneous tissue was infiltrated by spindle cells suggesting a neurofibroma [Figure 4] and [Figure 5].
|Figure 4: Histopathology (H and E 10×) Epidermis showing parakeratosis, club-shaped rete ridges, suprapapillary thinning, capillary proliferation in papillary dermis. Reticular dermis shows infiltration by spindle cells|
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|Figure 5: Histopathology (H and E 40×) — mass of spindle cells infiltrating dermis|
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Routine laboratory investigations were normal. Electrocardioram (ECG), two-dimensional echocardiogram (2D ECHO), ultrasonography (USG) of the abdomen, and magnetic resonance imaging (MRI) of the brain, were normal.
The patient was started on narrowband-ultraviolet B (NB-UVB) and topical steroids; and psoriatic lesions regressed within 4 weeks.
| Discussion|| |
NF-1 is an autosomal dominantly inherited neurocutaneous disorder characterized by multiple cutaneous neurofibromas, gliomas of optic nerve, lisch nodules over iris and café-au-lait macules. It is a common genetic disorder with a frequency of 1:3000. It is due to mutation in the NF-1 gene encoding for NF protein that inactivates the RAS family of guanosine triphosphate (GTP)ase-activating proteins. In NF-1 there is an increased activity of RAS proteins causing increased transduction of growth factors and mitogenesis leading to occurrence of neoplasms and proliferative conditions such as psoriasis. Psoriasis is a chronic proliferative condition characterized by epidermal proliferation, inflammation, and vascular changes. There are many growth factors responsible for pathogenesis , of psoriasis of which important mediators are EGF, TGF-alpha, and TNF-alpha. According to Peltonin et al., there is decreased NF in the lesions and increased RAS activity  in psoriatic skin suggesting pathogenesis similar to NF-1.
In the past, there were four reported cases in which neurofibromatosis and psoriasis coexisted. In 1990, Nishimura and Hori  reported a 58-year-old man with psoriasis vulgaris; neurofibromas had developed during psoralen + ultraviolet A treatment in 1985; Roenigk and Manick  reported a 57-year-old man with NF-1 and psoriasis. In 1999, Çelebi et al. reported a 7-year-old boy with neurofibromatosis who developed scalp psoriasis. In 2005, M Arica, SA Erdal et al. reported a 20-year-old female neurofibromatosis associated with psoriasis.
Our patient is a 28-year-old female with NF-1 and psoriasis, there is no family history of either. It is most likely that these two disorders occurred by chance as the occurrence of neurofibromatosis is 1:3000, and not every patient was developing psoriasis. The absence of reported cases suggests that a direct relationship between these two diseases is unlikely. Other reports of this combination would be of interest and could be expected statistically in the future.
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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], [Figure 5]